Retrofit2.0详解

综述

　　retrofit是由square公司开发的。square在github上发布了很多优秀的Android开源项目。例如:otto(事件总线),leakcanary(排查内存泄露),android-times-square(日历控件),dagger(依赖注入),picasso(异步加载图片),okhttp(网络请求),retrofit(网络请求)等等。更多square上的开源项目我们可以去square的GitHub进行查看。这次就来介绍一下retrofit的一些基本用法。retrofit是REST安卓客户端请求库。使用retrofit可以进行GET，POST，PUT，DELETE等请求方式。下面就来看一下retrofit的基本用法。

Retrofit使用方法

　　由于retrofit2.0与先前版本的差别还是比较大，对于不同版本之间的差异在这里就不在进行详细区别。下面的例子也是针对于retrofit2.0进行介绍的。retrofit2.0它依赖于OkHttp,而且这部分也不再支持替换。在这里我们也不需要显示的导入okHttp,在retrofit中已经导入okhttp3。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><dependency>
  <groupId>com.squareup.okhttp3</groupId>
  <artifactId>mockwebserver</artifactId>
  <scope>test</scope>
</dependency></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

　　在下面的例子当中采用与GitHub一些相关api进行演示。在这里首先需要添加访问网络的权限。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><uses-permission android:name=<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"android.permission.INTERNET"</span>/></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

简单示例

添加Gradle依赖项

　　在这里我们最好查看一下retrofit的官网添加最新依赖。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">compile <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'com.squareup.retrofit2:retrofit:2.0.1'</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

创建API接口

　　在retrofit中通过一个Java接口作为http请求的api接口。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">interface</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">GitHubApi</span> {</span>

    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@GET</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"repos/{owner}/{repo}/contributors"</span>)
    Call<ResponseBody> contributorsBySimpleGetCall(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Path</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"owner"</span>) String owner, <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Path</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"repo"</span>) String repo);
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

创建retrofit实例

　　在这里baseUrl是在创建retrofit实力的时候定义的，我们也可以在API接口中定义完整的url。在这里建议在创建baseUrl中以”/”结尾，在API中不以”/”开头和结尾。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">Retrofit retrofit = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Retrofit.Builder()
        .baseUrl(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"https://api.github.com/"</span>)
        .build();</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

调用API接口

　　在调用API接口请求后，获得一个json字符串，通过Gson进行解析，获得login以及contributions。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">GitHubApi repo = retrofit.create(GitHubApi.class);

    Call<ResponseBody> call = repo.contributorsBySimpleGetCall(mUserName, mRepo);
call.enqueue(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Callback<ResponseBody>() {
    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onResponse</span>(Call<ResponseBody> call, Response<ResponseBody> response) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
            Gson gson = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Gson();
            ArrayList<Contributor> contributorsList = gson.fromJson(response.body().string(), <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> TypeToken<List<Contributor>>(){}.getType());
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (Contributor contributor : contributorsList){
                Log.d(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"login"</span>,contributor.getLogin());
                Log.d(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"contributions"</span>,contributor.getContributions()+<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>);
            }
        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (IOException e) {
            e.printStackTrace();
        }
    }

    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onFailure</span>(Call<ResponseBody> call, Throwable t) {

    }
});</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li></ul>

效果展示

　　这样就完成了一个http请求，上面请求的完整地址为：https://api.github.com/repos/square/retrofit/contributors 
　　然后我们看一下运行结果: 

取消请求

　　我们可以终止一个请求。终止操作是对底层的httpclient执行cancel操作。即使是正在执行的请求，也能够立即终止。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">call.cancel();</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

转换器

　　在上面的例子中通过获取ResponseBody后，我们自己使用Gson来解析接收到的Json格式数据。在Retrofit中当创建一个Retrofit实例的时候可以为其添加一个Json转换器，这样就会自动将Json格式的响应体转换为所需要的Java对象。那么先来看一下如何根据已有的Json格式数据如何生成Java对象。当然我们可以根据已知的数据手动创建Java对象，也可以通过工具更具Json格式为我们自动生成Java对象。

自动生成Java对象

　　在这里介绍两种根据Json数据自动生成Java对象的工具。

jsonschema2pojo

　　可以通过访问jsonschema2pojo网站。先来看一下它的使用方法。 

　　上面配置中所选注解若是使用的Gson解析，可以选择Gson，当然没有也是可以的。对于@Generated注解若是需要保留的话添加如下依赖，也可以直接删除@Generated注解，没有任何影响。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">compile <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'org.glassfish:javax.annotation:10.0-b28'</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

GsonFormat

　　GsonFormat是AndroidStudio中的一个插件，在AndroidStudio的插件选项中直接搜索安装这个插件即可。在这里看一下是如何使用这个插件的。 

添加转换器

　　在这里我们需要为retrofit添加gson转换器的依赖。添加过converter-gson后不用再添加gson库。在converter-gson中已经包含gson。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">compile <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'com.squareup.retrofit2:converter-gson:2.0.1'</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

　　在这里先创建一个Java类Contributor，用来保存接收到的数据。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-class" style="box-sizing: border-box;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">class</span> <span class="hljs-title" style="box-sizing: border-box; color: rgb(102, 0, 102);">Contributor</span> {</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> String login;
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> Integer contributions;

    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> String <span class="hljs-title" style="box-sizing: border-box;">getLogin</span>() {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> login;
    }

    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setLogin</span>(String login) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.login = login;
    }

    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Integer <span class="hljs-title" style="box-sizing: border-box;">getContributions</span>() {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> contributions;
    }

    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">setContributions</span>(Integer contributions) {
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">this</span>.contributions = contributions;
    }
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul>

　　这时候修改我们的API接口。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@GET</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"repos/{owner}/{repo}/contributors"</span>)
Call<List<Contributor>> contributorsByAddConverterGetCall(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Path</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"owner"</span>) String owner, <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Path</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"repo"</span>) String repo);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

　　创建retrofit实例，我们通过addConverterFactory指定一个factory来对响应反序列化，在这里converters被添加的顺序将是它们被Retrofit尝试的顺序。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">Retrofit retrofit = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Retrofit.Builder()
        .baseUrl(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"https://api.github.com/"</span>)
        .addConverterFactory(GsonConverterFactory.create())
        .build();</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li></ul>

　　调用上面所修改的API接口。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">GitHubApi repo = retrofit.create(GitHubApi.class);
Call<List<Contributor>> call = repo.contributorsByAddConverterGetCall(mUserName, mRepo);
call.enqueue(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Callback<List<Contributor>>() {
    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onResponse</span>(Call<List<Contributor>> call, Response<List<Contributor>> response) {
        List<Contributor> contributorList = response.body();
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (Contributor contributor : contributorList){
            Log.d(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"login"</span>, contributor.getLogin());
            Log.d(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"contributions"</span>, contributor.getContributions() + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>);
        }
    }

    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onFailure</span>(Call<List<Contributor>> call, Throwable t) {

    }
});</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li></ul>

　　最后在来看一下运行结果。 

　　retrofit不仅仅只支持gson，还支持其他许多json解析库。以下版本号需要与retrofit版本号保持一致，并且以retrofit官网给出的版本号为准。

• Gson: compile 'com.squareup.retrofit2:converter-gson:2.0.1'
• Jackson: compile 'com.squareup.retrofit2:converter-jackson:2.0.1'
• Moshi: compile 'com.squareup.retrofit2:converter-moshi:2.0.1'
• Protobuf: compile 'com.squareup.retrofit2:converter-protobuf:2.0.1'
• Wire: compile 'com.squareup.retrofit2:converter-wire:2.0.1'
• Simple XML: compile 'com.squareup.retrofit2:converter-simplexml:2.0.1'
• Scalars (primitives, boxed, and String): compile 'com.squareup.retrofit2:converter-scalars:2.0.1'

增加日志信息

　　在retrofit2.0中是没有日志功能的。但是retrofit2.0中依赖OkHttp，所以也就能够通过OkHttp中的interceptor来实现实际的底层的请求和响应日志。在这里我们需要修改上一个retrofit实例，为其自定自定义的OkHttpClient。代码如下：

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">HttpLoggingInterceptor httpLoggingInterceptor = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> HttpLoggingInterceptor();
httpLoggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient okHttpClient = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> OkHttpClient.Builder()
        .addInterceptor(httpLoggingInterceptor)
        .build();

Retrofit retrofit = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Retrofit.Builder().addCallAdapterFactory(RxJavaCallAdapterFactory.create())
        .client(okHttpClient)
        .baseUrl(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"https://api.github.com/"</span>)
        .addConverterFactory(GsonConverterFactory.create())
        .build();</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul>

　　还需要添加如下依赖。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">compile <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'com.squareup.okhttp3:logging-interceptor:3.1.2'</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

　　其他代码没有任何变化，我们来看一下运行结果。 

添加请求头

　　我们可以通过@Headers来添加请求头。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Headers</span>({
        <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Accept: application/vnd.github.v3.full+json"</span>,
        <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"User-Agent: RetrofitBean-Sample-App"</span>,
        <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"name:ljd"</span>
})
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@GET</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"repos/{owner}/{repo}/contributors"</span>)
Call<List<Contributor>> contributorsAndAddHeader(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Path</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"owner"</span>) String owner,<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Path</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"repo"</span>) String repo);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li></ul>

　　运行结果。 

同步请求

　　在这里我们可以直接通过call.execute()执行一个同步请求，由于不允许在主线程中进行网络请求操作，所以我们需要再子线程中进行执行。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Thread(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Runnable() {
    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">run</span>() {

        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">try</span> {
            Response<List<Contributor>> response = call.execute();
            List<Contributor> contributorsList = response.body();
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (Contributor contributor : contributorsList){
                Log.d(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"login"</span>,contributor.getLogin());
                Log.d(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"contributions"</span>,contributor.getContributions()+<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">""</span>);
            }
        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">catch</span> (IOException e) {
            e.printStackTrace();
        }
    }
}).start();</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li></ul>

　　在这里看一下运行结果。 

clone

　　在这里无论是同步操作还是异步操作每一个call对象实例只能被执行一次。多次执行抛出如下异常。 

　　在这里如果我们的request和respone都是一一对应的。我们通过Clone方法创建一个一模一样的实例，并且它的开销也是很小的。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">Call<List<Contributor>> cloneCall = call.clone();
cloneCall.execute();</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

get请求

　　在前面的一些例子当中我们都是采用get请求。当然我们也可以为URL指定查询参数。使用@Query即可。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@GET</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"search/repositories"</span>)
Call<RetrofitBean> queryRetrofitByGetCall(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Query</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"q"</span>)String owner,
                                      <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Query</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"since"</span>)String time,
                                      <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Query</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"page"</span>)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> page,
                                      <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Query</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"per_page"</span>)<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> per_Page);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li></ul>

　　当我们的参数过多的时候我们可以通过@QueryMap注解和map对象参数来指定每个表单项的Key，value的值。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@GET</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"search/repositories"</span>)
Call<RetrofitBean> queryRetrofitByGetCallMap(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@QueryMap</span> Map<String,String> map);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

　　下面的call对象实例为上面api中所返回call对象。更具所返回的json数据所创建的实体类在这里就不在贴出代码，下载源码详细查看。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">call.enqueue(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Callback<RetrofitBean>() {
    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onResponse</span>(Call<RetrofitBean> call, Response<RetrofitBean> response) {
        RetrofitBean retrofit = response.body();
        List<Item> list = retrofit.getItems();
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (list == <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">null</span>)
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span>;
        Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"total:"</span> + retrofit.getTotalCount());
        Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"incompleteResults:"</span> + retrofit.getIncompleteResults());
        Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"----------------------"</span>);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (Item item : list) {
            Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"name:"</span> + item.getName());
            Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"full_name:"</span> + item.getFull_name());
            Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"description:"</span> + item.getDescription());
            Owner owner = item.getOwner();
            Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"login:"</span> + owner.getLogin());
            Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"type:"</span> + owner.getType());
        }

    }

    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onFailure</span>(Call<RetrofitBean> call, Throwable t) {

    }
});</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li></ul>

　　上面请求中的完整连接为: https://api.github.com/search/repositories?q=retrofit&since=2016-03-29&page=1&per_page=3，运行结果如下。 

　　在Retrofit 2.0添加了一个新的注解：@Url，它允许我们直接传入一个请求的URL。这样以来我们可以将上一个请求的获得的url直接传入进来。方便了我们的操作。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@GET</span>
Call<List<Contributor>> repoContributorsPaginate(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Url</span> String url);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

Form encoded和Multipart

Form encoded

　　我们可以使用@FormUrlEncoded注解来发送表单数据。使用 @Field注解和参数来指定每个表单项的Key，value为参数的值。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@FormUrlEncoded</span>
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@POST</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"user/edit"</span>)
Call<User> updateUser(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Field</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"first_name"</span>) String first, <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Field</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"last_name"</span>) String last);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

　　当我们有很多个表单参数时可以通过@FieldMap注解和Map对象参数来指定每个表单项的Key，value的值。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@FormUrlEncoded</span>
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@POST</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"user/edit"</span>)
Call<User> updateUser(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@FieldMap</span> Map<String,String> fieldMap);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

Multipart

　　我们还可以通过@Multipart注解来发送Multipart数据。通过@Part注解来定义需要发送的文件。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Multipart</span>
<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@PUT</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"/user/photo"</span>)
User updateUser(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Part</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"photo"</span>) TypedFile photo, <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Part</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"description"</span>) TypedString description);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

Retrofit与RxJava结合

　　Retrofit能够与RxJava进行完美结合。下面就来看一下Retrofit与RxJava是如何结合在一起的。对于RxJava在这就不在进行详细介绍，对于RXJava的使用可以参考附录里面给出链接。 
　　首先我们需要添加如下依赖。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">compile <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'com.squareup.retrofit2:adapter-rxjava:2.0.1'</span>
compile <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">'io.reactivex:rxandroid:1.1.0'</span></code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

　　创建retrofit对象实例时，通过addCallAdapterFactory来添加对RxJava的支持。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">HttpLoggingInterceptor httpLoggingInterceptor = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> HttpLoggingInterceptor();
httpLoggingInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);
OkHttpClient okHttpClient = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> OkHttpClient.Builder()
        .addInterceptor(httpLoggingInterceptor)
        .build();
Retrofit retrofit = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Retrofit.Builder()
        .client(okHttpClient)
        .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
        .addConverterFactory(GsonConverterFactory.create())
        .baseUrl(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"https://api.github.com/"</span>)
        .build();</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li></ul>

　　使用Observable创建一个API接口。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@GET</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"repos/{owner}/{repo}/contributors"</span>)
Observable<List<Contributor>> contributorsByRxJava(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Path</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"owner"</span>) String owner,<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Path</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"repo"</span>) String repo);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li></ul>

　　下面来调用这个API接口。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> CompositeSubscription mSubscriptions = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> CompositeSubscription();</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li></ul>

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">mSubscriptions.add(
        mGitHubService.contributorsByRxJava(mUserName, mRepo)
                .subscribeOn(Schedulers.io())
                .observeOn(AndroidSchedulers.mainThread())
                .subscribe(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Observer<List<Contributor>>() {
                    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onCompleted</span>() {
                    }

                    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onError</span>(Throwable e) {
                    }

                    <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
                    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onNext</span>(List<Contributor> contributors) {
                        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">for</span> (Contributor c : contributors) {
                            Log.d(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"TAG"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"login:"</span> + c.getLogin() + <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"  contributions:"</span> + c.getContributions());
                        }
                    }
                }));</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li></ul>

　　下面来看一下运行结果。 

　　如果我们想要查看所有contributor的信息，首先我们需要向gitHub请求获取到所有contributor，然后再通过获得contributor进行依次向github请求获取contributor的信息，在这时候我们使用RxJava也就非常方便了。下面看一下如何操作的。 
　　首先再添加一个API接口。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@GET</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"repos/{owner}/{repo}/contributors"</span>)
Observable<List<Contributor>> contributorsByRxJava(<span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Path</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"owner"</span>) String owner,
                                                   <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Path</span>(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"repo"</span>) String repo);</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li></ul>

　　下面在看一下是如何进行根据获得的contributor来查看contributor的信息。

<code class="hljs java has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;">mSubscriptions.add(mGitHubService.contributorsByRxJava(mUserName, mRepo)
        .flatMap(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Func1<List<Contributor>, Observable<Contributor>>() {
            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Observable<Contributor> <span class="hljs-title" style="box-sizing: border-box;">call</span>(List<Contributor> contributors) {
                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> Observable.from(contributors);
            }
        })
        .flatMap(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Func1<Contributor, Observable<Pair<User, Contributor>>>() {
            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Observable<Pair<User, Contributor>> <span class="hljs-title" style="box-sizing: border-box;">call</span>(Contributor contributor) {
                Observable<User> userObservable = mGitHubService.userByRxJava(contributor.getLogin())
                        .filter(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Func1<User, Boolean>() {
                            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
                            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Boolean <span class="hljs-title" style="box-sizing: border-box;">call</span>(User user) {
                                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> !isEmpty(user.getName()) && !isEmpty(user.getEmail());
                            }
                        });

                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> Observable.zip(userObservable,
                        Observable.just(contributor),
                        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Func2<User, Contributor, Pair<User, Contributor>>() {
                            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
                            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> Pair<User, Contributor> <span class="hljs-title" style="box-sizing: border-box;">call</span>(User user, Contributor contributor) {
                                <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Pair<>(user, contributor);
                            }
                        });
            }
        })
        .subscribeOn(Schedulers.newThread())
        .observeOn(AndroidSchedulers.mainThread())
        .subscribe(<span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Observer<Pair<User, Contributor>>() {
            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onCompleted</span>() {

            }

            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onError</span>(Throwable e) {

            }

            <span class="hljs-annotation" style="color: rgb(155, 133, 157); box-sizing: border-box;">@Override</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">public</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">void</span> <span class="hljs-title" style="box-sizing: border-box;">onNext</span>(Pair<User, Contributor> pair) {
                User user = pair.first;
                Contributor contributor = pair.second;
                Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"name:"</span> + user.getName());
                Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"contributions:"</span> + contributor.getContributions());
                Log.d(TAG, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"email:"</span> + user.getEmail());

            }
        }));</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li><li style="box-sizing: border-box; padding: 0px 5px;">40</li><li style="box-sizing: border-box; padding: 0px 5px;">41</li><li style="box-sizing: border-box; padding: 0px 5px;">42</li><li style="box-sizing: border-box; padding: 0px 5px;">43</li><li style="box-sizing: border-box; padding: 0px 5px;">44</li><li style="box-sizing: border-box; padding: 0px 5px;">45</li><li style="box-sizing: border-box; padding: 0px 5px;">46</li><li style="box-sizing: border-box; padding: 0px 5px;">47</li><li style="box-sizing: border-box; padding: 0px 5px;">48</li><li style="box-sizing: border-box; padding: 0px 5px;">49</li><li style="box-sizing: border-box; padding: 0px 5px;">50</li><li style="box-sizing: border-box; padding: 0px 5px;">51</li></ul>

　　最后在来看下运行结果。 

Retrofit设置缓存

对Retrofit设置缓存，由于Retrofit是对OkHttp的封装，所以我们可以直接通过OkHttpClient着手。也就是为OkHttp设置缓存。设置缓存代码如下所示。

<code class="language-java hljs  has-numbering" style="display: block; padding: 0px; color: inherit; box-sizing: border-box; font-family: 'Source Code Pro', monospace;font-size:undefined; white-space: pre; border-radius: 0px; word-wrap: normal; background: transparent;"><span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">private</span> OkHttpClient <span class="hljs-title" style="box-sizing: border-box;">getCacheOkHttpClient</span>(Context context){
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> File baseDir = context.getCacheDir();
    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">final</span> File cacheDir = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> File(baseDir, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"HttpResponseCache"</span>);
    Timber.e(cacheDir.getAbsolutePath());
    Cache cache = <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> Cache(cacheDir, <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">10</span> * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1024</span> * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">1024</span>);   <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//缓存可用大小为10M</span>

    Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = chain -> {
        Request request = chain.request();
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span>(!NetWorkUtils.isNetWorkAvailable(context)){
            request = request.newBuilder()
                    .cacheControl(CacheControl.FORCE_CACHE)
                    .build();
        }

        Response originalResponse = chain.proceed(request);
        <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">if</span> (NetWorkUtils.isNetWorkAvailable(context)) {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> maxAge = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">60</span>;                  <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//在线缓存一分钟</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> originalResponse.newBuilder()
                    .removeHeader(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Pragma"</span>)
                    .removeHeader(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Cache-Control"</span>)
                    .header(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Cache-Control"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"public, max-age="</span> + maxAge)
                    .build();

        } <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">else</span> {
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">int</span> maxStale = <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">60</span> * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">60</span> * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">24</span> * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">4</span> * <span class="hljs-number" style="color: rgb(0, 102, 102); box-sizing: border-box;">7</span>;     <span class="hljs-comment" style="color: rgb(136, 0, 0); box-sizing: border-box;">//离线缓存4周</span>
            <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> originalResponse.newBuilder()
                    .removeHeader(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Pragma"</span>)
                    .removeHeader(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Cache-Control"</span>)
                    .header(<span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"Cache-Control"</span>, <span class="hljs-string" style="color: rgb(0, 136, 0); box-sizing: border-box;">"public, only-if-cached, max-stale="</span> + maxStale)
                    .build();
        }
    };

    <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">return</span> <span class="hljs-keyword" style="color: rgb(0, 0, 136); box-sizing: border-box;">new</span> OkHttpClient.Builder()
            .addNetworkInterceptor(REWRITE_CACHE_CONTROL_INTERCEPTOR)
            .addInterceptor(REWRITE_CACHE_CONTROL_INTERCEPTOR)
            .cache(cache)
            .build();
}</code><ul class="pre-numbering" style="box-sizing: border-box; position: absolute; width: 50px; top: 0px; left: 0px; margin: 0px; padding: 6px 0px 40px; border-right-width: 1px; border-right-style: solid; border-right-color: rgb(221, 221, 221); list-style: none; text-align: right; background-color: rgb(238, 238, 238);"><li style="box-sizing: border-box; padding: 0px 5px;">1</li><li style="box-sizing: border-box; padding: 0px 5px;">2</li><li style="box-sizing: border-box; padding: 0px 5px;">3</li><li style="box-sizing: border-box; padding: 0px 5px;">4</li><li style="box-sizing: border-box; padding: 0px 5px;">5</li><li style="box-sizing: border-box; padding: 0px 5px;">6</li><li style="box-sizing: border-box; padding: 0px 5px;">7</li><li style="box-sizing: border-box; padding: 0px 5px;">8</li><li style="box-sizing: border-box; padding: 0px 5px;">9</li><li style="box-sizing: border-box; padding: 0px 5px;">10</li><li style="box-sizing: border-box; padding: 0px 5px;">11</li><li style="box-sizing: border-box; padding: 0px 5px;">12</li><li style="box-sizing: border-box; padding: 0px 5px;">13</li><li style="box-sizing: border-box; padding: 0px 5px;">14</li><li style="box-sizing: border-box; padding: 0px 5px;">15</li><li style="box-sizing: border-box; padding: 0px 5px;">16</li><li style="box-sizing: border-box; padding: 0px 5px;">17</li><li style="box-sizing: border-box; padding: 0px 5px;">18</li><li style="box-sizing: border-box; padding: 0px 5px;">19</li><li style="box-sizing: border-box; padding: 0px 5px;">20</li><li style="box-sizing: border-box; padding: 0px 5px;">21</li><li style="box-sizing: border-box; padding: 0px 5px;">22</li><li style="box-sizing: border-box; padding: 0px 5px;">23</li><li style="box-sizing: border-box; padding: 0px 5px;">24</li><li style="box-sizing: border-box; padding: 0px 5px;">25</li><li style="box-sizing: border-box; padding: 0px 5px;">26</li><li style="box-sizing: border-box; padding: 0px 5px;">27</li><li style="box-sizing: border-box; padding: 0px 5px;">28</li><li style="box-sizing: border-box; padding: 0px 5px;">29</li><li style="box-sizing: border-box; padding: 0px 5px;">30</li><li style="box-sizing: border-box; padding: 0px 5px;">31</li><li style="box-sizing: border-box; padding: 0px 5px;">32</li><li style="box-sizing: border-box; padding: 0px 5px;">33</li><li style="box-sizing: border-box; padding: 0px 5px;">34</li><li style="box-sizing: border-box; padding: 0px 5px;">35</li><li style="box-sizing: border-box; padding: 0px 5px;">36</li><li style="box-sizing: border-box; padding: 0px 5px;">37</li><li style="box-sizing: border-box; padding: 0px 5px;">38</li><li style="box-sizing: border-box; padding: 0px 5px;">39</li></ul>

总结

　　在retrofit的使用中，对于文件你上传与下载，并没有为我们提供进度更新的接口，在这里就需要我们自己处理了。在下面的例子中给出一个文件下载的例子，并且对下载进度更新通过logcat打印出来。可以下载进行查看。到这里retrofit的基本用法也就介绍完了，对于retrofit更多的好处在使用中我们可以慢慢体会。

源码下载

附录

• Retrofit官方文档
• 用 Retrofit 2 简化 HTTP 请求
• 给 Android 开发者的 RxJava 详解
• RxJava Essentials 中文翻译版