Retrofit retrofit = new Retrofit.Builder().baseUrl("https://www.baidu.com").addConverterFactory
(GsonConverterFactory.create()).build();
步骤 1
这个函数做了什么呢?
1.对变量是否为空判断,并附上默认的值 2.然后new 出retrofit
public Retrofit build() {
if (baseUrl == null) {
throw new IllegalStateException("Base URL required.");
}
okhttp3.Call.Factory callFactory = this.callFactory;
if (callFactory == null) {
callFactory = new OkHttpClient();
}
Executor callbackExecutor = this.callbackExecutor;
if (callbackExecutor == null) {
callbackExecutor = platform.defaultCallbackExecutor();
}
// Make a defensive copy of the adapters and add the default Call adapter.
List callAdapterFactories = new ArrayList<>(this.callAdapterFactories);
callAdapterFactories.addAll(platform.defaultCallAdapterFactories(callbackExecutor));
// Make a defensive copy of the converters.
List converterFactories = new ArrayList<>(
1 + this.converterFactories.size() + platform.defaultConverterFactoriesSize());
// Add the built-in converter factory first. This prevents overriding its behavior but also
// ensures correct behavior when using converters that consume all types.
converterFactories.add(new BuiltInConverters());
converterFactories.addAll(this.converterFactories);
converterFactories.addAll(platform.defaultConverterFactories());
return new Retrofit(callFactory, baseUrl, unmodifiableList(converterFactories),
unmodifiableList(callAdapterFactories), callbackExecutor, validateEagerly);
}
}
步骤2 设置配置参数
这里只是举两个配置参数的例子
public Builder baseUrl(HttpUrl baseUrl) {
checkNotNull(baseUrl, "baseUrl == null");
List pathSegments = baseUrl.pathSegments();
if (!"".equals(pathSegments.get(pathSegments.size() - 1))) {
throw new IllegalArgumentException("baseUrl must end in /: " + baseUrl);
}
this.baseUrl = baseUrl;
return this;
}
/** Add converter factory for serialization and deserialization of objects. */
public Builder addConverterFactory(Converter.Factory factory) {
converterFactories.add(checkNotNull(factory, "factory == null"));
return this;
}
步骤3 分析Retrofit常量&方法
public final class Retrofit {
private final Map> serviceMethodCache = new ConcurrentHashMap<>();
final okhttp3.Call.Factory callFactory;
final HttpUrl baseUrl;//请求URL
final List converterFactories;//数据转换器集合
final List callAdapterFactories;//网络请求适配器集合
final @Nullable Executor callbackExecutor;//线程切换执行器
final boolean validateEagerly;//验证
Retrofit(okhttp3.Call.Factory callFactory, HttpUrl baseUrl,
List converterFactories, List callAdapterFactories,
@Nullable Executor callbackExecutor, boolean validateEagerly) {
this.callFactory = callFactory;
this.baseUrl = baseUrl;
this.converterFactories = converterFactories; // Copy+unmodifiable at call site.
this.callAdapterFactories = callAdapterFactories; // Copy+unmodifiable at call site.
this.callbackExecutor = callbackExecutor;
this.validateEagerly = validateEagerly;
}
变量详解
1.HttpUrl baseUrl
/**
* Set the API base URL.
*
* @see #baseUrl(HttpUrl)
*把String类型的url参数转化为适合OKhttp的HttpUrl类型
*/
public Builder baseUrl(String baseUrl) {
checkNotNull(baseUrl, "baseUrl == null");
return baseUrl(HttpUrl.get(baseUrl));
}
/**
* Set the API base URL.
*
* @see #baseUrl(HttpUrl)
*/
public Builder baseUrl(URL baseUrl) {
checkNotNull(baseUrl, "baseUrl == null");
return baseUrl(HttpUrl.get(baseUrl.toString()));
}
/**
* Set the API base URL.
*
* @see #baseUrl(URL)
*/
public Builder baseUrl(HttpUrl baseUrl) {
checkNotNull(baseUrl, "baseUrl == null");//检测是否空
List pathSegments = baseUrl.pathSegments();//切割判断
//判断最后一个字段要以 / 结尾
if (!"".equals(pathSegments.get(pathSegments.size() - 1))) {
throw new IllegalArgumentException("baseUrl must end in /: " + baseUrl);
}
this.baseUrl = baseUrl;
return this;
}
/**
*通过注解方式获取配置对象 实现缓存
*/
ServiceMethod> loadServiceMethod(Method method) {
ServiceMethod> result = serviceMethodCache.get(method);
if (result != null) return result;
synchronized (serviceMethodCache) {
result = serviceMethodCache.get(method);
if (result == null) {
result = ServiceMethod.parseAnnotations(this, method);
serviceMethodCache.put(method, result);
}
}
return result;
}
private void parseMethodAnnotation(Annotation annotation) {
if (annotation instanceof DELETE) {
parseHttpMethodAndPath("DELETE", ((DELETE) annotation).value(), false);
} else if (annotation instanceof GET) {
parseHttpMethodAndPath("GET", ((GET) annotation).value(), false);
} else if (annotation instanceof HEAD) {
parseHttpMethodAndPath("HEAD", ((HEAD) annotation).value(), false);
} else if (annotation instanceof PATCH) {
parseHttpMethodAndPath("PATCH", ((PATCH) annotation).value(), true);
} else if (annotation instanceof POST) {
parseHttpMethodAndPath("POST", ((POST) annotation).value(), true);
} else if (annotation instanceof PUT) {
parseHttpMethodAndPath("PUT", ((PUT) annotation).value(), true);
} else if (annotation instanceof OPTIONS) {
parseHttpMethodAndPath("OPTIONS", ((OPTIONS) annotation).value(), false);
} else if (annotation instanceof HTTP) {
HTTP http = (HTTP) annotation;
parseHttpMethodAndPath(http.method(), http.path(), http.hasBody());
} else if (annotation instanceof retrofit2.http.Headers) {
String[] headersToParse = ((retrofit2.http.Headers) annotation).value();
if (headersToParse.length == 0) {
throw methodError(method, "@Headers annotation is empty.");
}
headers = parseHeaders(headersToParse);
} else if (annotation instanceof Multipart) {
if (isFormEncoded) {
throw methodError(method, "Only one encoding annotation is allowed.");
}
isMultipart = true;
} else if (annotation instanceof FormUrlEncoded) {
if (isMultipart) {
throw methodError(method, "Only one encoding annotation is allowed.");
}
isFormEncoded = true;
}
}
主要分方法
1.动态方法实现注解接口
public T create(final Class service) {
Utils.validateServiceInterface(service);
if (validateEagerly) {
eagerlyValidateMethods(service);
}
return (T) Proxy.newProxyInstance(service.getClassLoader(), new Class>[] { service },
new InvocationHandler() {
private final Platform platform = Platform.get();
private final Object[] emptyArgs = new Object[0];
@Override public Object invoke(Object proxy, Method method, @Nullable Object[] args)
throws Throwable {
// If the method is a method from Object then defer to normal invocation.
if (method.getDeclaringClass() == Object.class) {
return method.invoke(this, args);
}
if (platform.isDefaultMethod(method)) {
return platform.invokeDefaultMethod(method, service, proxy, args);
}
return loadServiceMethod(method).invoke(args != null ? args : emptyArgs);
}
});
}
2.解析缓存注解等参数
ServiceMethod> loadServiceMethod(Method method) {
ServiceMethod> result = serviceMethodCache.get(method);
if (result != null) return result;
synchronized (serviceMethodCache) {
result = serviceMethodCache.get(method);
if (result == null) {
result = ServiceMethod.parseAnnotations(this, method);
serviceMethodCache.put(method, result);
}
}
return result;
}
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包冲突是开发过程中很常见的问题:
其表现有:
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2.明明在eclipse中能够索引到某个类的方法,运行时却报出找不到方法。
3.类及方法都有,以正确编译成了.class文件,在本机跑的好好的,发到测试或者正式环境就
抛如下异常:
java.lang.NoClassDefFoundError: Could not in
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SYNOPSIS:
gpasswd group
gpasswd -a user group
gpasswd -d user group
gpasswd -R group
gpasswd -r group
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yum list installed | grep mysql
yum -y remove mysql-libs.x86_64
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install mysq
Given a string s1, we may represent it as a binary tree by partitioning it to two non-empty substrings recursively.
Below is one possible representation of s1 = "great":
select p.spid,c.object_name,b.session_id,b.oracle_username,b.os_user_name from v$process p,v$session a, v$locked_object b,all_objects c where p.addr=a.paddr and a.process=b.process and c.object_id=b.