Android网络请求

在Android开发时，很多情况下都会用到请求获取接口数据或者请求向服务器提交数据。

目前较为流行的用法是retrofit2与okhttp3相结合进行网络请求

下面介绍具体使用方法：

目录

介绍封装完成的网络请求包retrofit

CallBack接口 

ApiService接口

ApiBuilder类

ApiClient类

retrofit包具体使用 

插件GsonFormatPlus设置

插件的具体使用

网络请求的具体模板

GET请求

Post提交数据请求

---

介绍封装完成的网络请求包retrofit

1.首先介绍封装好的网络请求包retrofit：

        retrofit包内有2个Java类与两个Java 接口

        ApiBuilder类主要是来建立请求头，而ApiClient类则是进行具体的请求并对请求体解析

        CallBack接口内是抽象了请求体的两个解析函数，ApiService内是抽象的请求方法接口

        具体代码如下：

2. 导入依赖：

  implementation 'com.squareup.okhttp3:okhttp:3.11.0'
  implementation 'com.squareup.retrofit2:retrofit:2.4.0'
  implementation 'com.squareup.retrofit2:converter-gson:2.4.0'

CallBack接口 

public interface CallBack {

    public void onResponse(T data);

    public void onFail(String msg);

}

ApiService接口

import java.util.Map;

import okhttp3.FormBody;
import okhttp3.RequestBody;
import okhttp3.ResponseBody;
import retrofit2.Call;
import retrofit2.http.Body;
import retrofit2.http.FieldMap;
import retrofit2.http.FormUrlEncoded;
import retrofit2.http.GET;
import retrofit2.http.HeaderMap;
import retrofit2.http.POST;
import retrofit2.http.Path;
import retrofit2.http.Query;
import retrofit2.http.QueryMap;
import retrofit2.http.Url;

public interface ApiService {


    @GET("{name}")
    Call getCityAndCommunityData(@Path(value = "name", encoded = true) String name, @Query("cityId") String id);

    @GET("{name}")
    Call getNoticeHtml(@Path(value = "name", encoded = true) String name);

    @POST()
    Call post(@HeaderMap Map headers, @Url String url, @Body RequestBody  body);

    @POST()
    Call post( @Url String url, @Body RequestBody  body);

    @POST()
    Call post( @Url String url, @Body FormBody body);

    @POST()
    Call post(@HeaderMap Map headers, @Url String url);

    @GET()
    Call get(@HeaderMap Map headers, @Url String url, @QueryMap Map params);

    @GET("{name}")
    Call getPaymentList(@Path(value = "name", encoded = true) String name, @Query("houseId") String houseId, @Query("expenseId") String expenseId);

    @FormUrlEncoded
    @POST("{name}")
    Call postUnitData(@Path("name") String name, @FieldMap Map params);

    @GET("{name}")
    Call getBoundCommunity(@Path("name") String name);

    @POST("{name}")
    Call submitRepair(@Path(value = "name", encoded = true)String name, @Body RequestBody data);

}

ApiBuilder类

import java.util.HashMap;
import java.util.Map;

import okhttp3.RequestBody;

public class ApiBuilder {

    Map params ;
    Map headers ;
    RequestBody body;
    String url;

    public ApiBuilder Body(RequestBody  body){
        this.body = body;
        return this;
    }

    public ApiBuilder Params(Map params) {
        this.params.putAll(params);
        return this;
    }

    public ApiBuilder Params(String key, String value) {
        this.params.put(key, value);
        return this;
    }

    public ApiBuilder Headers(Map headers) {
        this.headers.putAll(headers);
        return this;
    }

    public ApiBuilder Headers(String key, String value) {
        this.headers.put(key, value);
        return this;
    }

    public ApiBuilder Url(String url) {
        this.url = url;
        return this;
    }

    public ApiBuilder(String url) {
        this.setParams(url);
    }

    public ApiBuilder() {
        this.setParams(null);
    }


    private void setParams(String url) {
        this.url = url;
        this.params = new HashMap<>();
        this.headers = new HashMap<>();
    }

}

ApiClient类

import android.content.Context;
import android.util.Log;

import com.example.hp.brainpower.constant.ConstantUrl;
import com.google.gson.Gson;

import java.io.IOException;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import okhttp3.Headers;
import okhttp3.ResponseBody;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;

public class ApiClient {

    private static ApiClient instance;

    /***
     *
     * 构建 retrofit请求
     * */
    private final static Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(ConstantUrl.BASE_URL) //这里是你的根Url，最后要用/结尾
            .build();


    /**
     * 获取service实例
     *
     * @return get或者post请求接口
     */
    public ApiService getService() {
        return retrofit.create(ApiService.class);
    }

    /**
     * 创建请求单例
     *
     * @return
     */
    public static ApiClient getInstance() {

        if (instance == null) {
            synchronized (ApiClient.class) {
                if (instance == null) {
                    instance = new ApiClient();
                }
            }
        }
        return instance;
    }

    /**
     * post请求 带token
     *
     * @param builder    request构建的参数 包含 url header params
     * @param onCallback rquest 回调
     * @param classOf    指定请求的model类型
     */

    public  void doPost(ApiBuilder builder, final CallBack onCallback, final Class classOf, Context context) {
        ApiService service = getService();
        Call call;
      /*  call = service.post(builder.url, builder.body);*/
        call = service.post(builder.headers, builder.url, builder.body);
        call.enqueue(new Callback() {
            @Override
            public void onResponse(Call call, Response response) {
                Log.d("kevin", String.valueOf(response));
                Object o = null;
                try {
                    if (response.body() == null) {
                        onCallback.onFail("失败" + response.message() + response.code());
                    } else {
                        String s = response.body().string();
                        o = new Gson().fromJson(s, classOf);
                        onCallback.onResponse((T) o);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                    String s = e.toString();
                    onCallback.onFail("失败");
                }
            }

            @Override
            public void onFailure(Call call, Throwable t) {
                onCallback.onFail(t.getMessage());
                Log.d("NET---", t.getMessage());
            }
        });
    }

    /**
     * get请求 带token
     *
     * @param builder    request构建的参数 包含 url header params
     * @param onCallback rquest 回调
     * @param classOf    指定请求的model类型
     *                   

     *                   

     *                   _ = userId，_t = 请求时间，token = MD5(token+_t)
     */

    public  void doGet(ApiBuilder builder, final CallBack onCallback, final Class classOf, final Context context) {

        ApiService service = getService();

        Call call = service.get(checkHeaders(builder.headers), builder.url, checkParams(builder.params));

        call.enqueue(new Callback() {
            @Override
            public void onResponse(Call call, Response response) {
                Log.d("result:", response.toString());
                Object o = null;
                try {
                    if (response.body() == null) {
                        String err = response.errorBody().string();
                        onCallback.onFail("失败");
                        Log.i("err", err);
                    } else {
                        o = new Gson().fromJson(response.body().string(), classOf);
                        onCallback.onResponse((T) o);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                    onCallback.onFail("失败");
                } catch (Exception e) {
                    e.printStackTrace();
                    onCallback.onFail("异常");
                }
            }

            @Override
            public void onFailure(Call call, Throwable t) {
                onCallback.onFail(t.getMessage());
                Log.d("NET---", t.getMessage());
            }
        });
    }

    /**
     * get请求 不带token
     *
     * @param builder    request构建的参数 包含 url header params
     * @param onCallback rquest 回调
     * @param classOf    指定请求的model类型
     */

    public  void doGetSaveSession(ApiBuilder builder, final CallBack onCallback, final Class classOf, final Context context) {

        ApiService service = getService();
        Call call = service.get(checkHeaders(builder.headers), builder.url, checkParams(builder.params));
        call.enqueue(new Callback() {
            @Override
            public void onResponse(Call call, Response response) {

                Object o = null;
                try {
                    if (response.body() != null) {
                        o = new Gson().fromJson(response.body().string(), classOf);
                        onCallback.onResponse((T) o);

                    } else {
                        onCallback.onFail("请检查网络重试");
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
                Headers headers = response.headers();
                List cookies = headers.values("Set-Cookie");
                if (cookies.size() > 0) {
                    String s = cookies.get(0);
                    String session = s.substring(0, s.indexOf(";"));
                    Log.i("存session", session);
                }

            }

            @Override
            public void onFailure(Call call, Throwable t) {
                onCallback.onFail(t.getMessage());
                Log.d("NET---", t.getMessage());
            }
        });
    }

    public static Map checkHeaders(Map headers) {
        if (headers == null) {
            headers = new HashMap<>();
        }
        //retrofit的headers的值不能为null，此处做下校验，防止出错
        for (Map.Entry entry : headers.entrySet()) {
            if (entry.getValue() == null) {
                headers.put(entry.getKey(), "");
            }
        }
        return headers;
    }

    public static Map checkParams(Map params) {
        if (params == null) {
            params = new HashMap<>();
        }
        //retrofit的params的值不能为null，此处做下校验，防止出错
        for (Map.Entry entry : params.entrySet()) {
            if (entry.getValue() == null) {
                params.put(entry.getKey(), "");
            }
        }
        return params;
    }

}

retrofit包具体使用 

2.retrofit包的具体使用

   首先声明ApiBuilder添加请求链接Url、请求头Headers和请求参数Params

   然后调用ApiClient.getInstance()的doGet、doPost、doGetSaveSession方法，进行get或post请求

   实体类的生成可以通过Android Studio插件GsonFormatPlus即可

插件GsonFormatPlus设置

   插件的具体设置如下：

GsonFormatPlus插件设置

插件的具体使用

 插件的具体使用如下：

     1.新建类，在类内使用Alt Insert（或者类内右击鼠标点击Generate GsonFormatPlus）  即可打开插件窗口

     2.在插件的JSON框内粘贴所要获取的接口数据，例如下列数据：

{"message":"Success","success":true,"data":{"total_sc":71.0,"safe_sc":72.0,"experience_sc":61.0,"finance_sc":57.0,"car_sc":72.0}}

  点击Format按钮进行JSON数据的格式化，具体如下图：

  

点击OK按钮，进行类内属性的生成，如有包装类修改为基本类型：

再点击OK按钮即生成所对应接口数据的实体类

网络请求的具体模板

GET请求

 进行GET网络请求的具体模版如下：     

ApiBuilder builder=new ApiBuilder()
                        .Url("car")//这里填根Url后的部分
                        .Headers("token",value)//请求头 键,值
                        .Params("key",value)//请求参数 键,值
                        .Params("key",value);//参数可以有多个
ApiClient.getInstance().doGet(builder,new CallBack(){
            //BeanClass为解析接口数据得到的实体类
            @Override
            public void onResponse(BeanClass data) {
                if (data.isSuccess()){ //获取接口数据成功
                     //请求体处理
                }else {
                    //请求失败处理 Activity.this为当前活动.this                                          
                    Toast.makeText(Activity.this,data.getMsg(),Toast.LENGTH_SHORT).show();
                }
            }

            @Override
            public void onFail(String msg) {
                Toast.makeText(Activity.this,msg,Toast.LENGTH_SHORT).show();
            }
        }, BeanClass.class, this);
//doPost请求和doGetSaveSession请求类似上述处理

Post提交数据请求

一般post请求需要向后端提交json格式的数据，这里提交的数据我们可以以请求体的形式上传

• 构建请求体

构建请求体是通过HashMap构建，通过添加键值对来添加提交信息，最后再将字典转成JSONObject格式的字符串

具体代码及注释如下：

HashMapmap=new HashMap<>();
map.put("model_id",mode);//向服务器提交的信息
JSONObject object=new JSONObject(map);#HashMap转JSONObject对象
String str=object.toString();#转换成JSON字符串
RequestBody body=RequestBody.create(MediaType.parse("application/json;charset=UTF-8"),str);#创建请求体，create第一个参数是请求头及编码格式，第二个参数是JSON字符串

• Post请求

发送Post请求

ApiBuilder builder=new ApiBuilder().Url(StringConstant.POST_MODEL).Headers("Content-Type","application/json").Body(body);
ApiClient.getInstance().doPost(builder, new CallBack() {
    @Override
    public void onResponse(PostCodeBean data) {
        if (data.getRes()==0){
            Toast.makeText(getContext(),"设置成功",Toast.LENGTH_SHORT).show();
        }else{
            Toast.makeText(getContext(),"设置失败",Toast.LENGTH_SHORT).show();

        }
    }
    @Override
    public void onFail(String msg) {
        System.out.println(msg);
    }
},PostCodeBean.class,getContext());