导航
1、retrofit-mock用法
2、retrofit-mock编写思路(aop)
3 、retrofit-mock的动态代理及注解
4、aspect 原理讲解与注解语法
1、retrofit-mock编写思路（动态代理基础上，再动态代理）
retrofit核心代码 精简省略不必要代码
public <T> T create(final Class<T> service) {
return (T) Proxy.newProxyInstance(service.getClassLoader(), new Class<?>[] { service },
new InvocationHandler() {
private final Object[] emptyArgs = new Object[0];
@Override public @Nullable Object invoke(Object proxy, Method method,
@Nullable Object[] args) throws Throwable {
return loadServiceMethod(method).invoke(args != null ? args : emptyArgs);
}
});
}
retrofit 核心是采用反向代理生成 T 的实体类
同样我们可以在这个生成实体类的基础上，再次动态代理，hook 调用函数
//获得值
T api = retrofit.create(Api.class);
//根据api实例，用反向代理，
Proxy.newProxyInstance( service.getClassLoader(), new Class<?>[]{service}, new MockerHandler( retrofit, api ) );
在实例api的基础上，再次动态代理
public class MockerHandler<T> implements InvocationHandler {
private Retrofit retrofit;
private T api;
public MockerHandler(Retrofit retrofit, T api) {
this.retrofit = retrofit;
this.api = api;
}
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
//method 方法就是对应的Api接口方法,
//可以在此处一通骚操作，处理retrofit
return method.invoke( api, args );
}
2、运行时注解，避免不必要手写代码，配置化操作
@Retention(RetentionPolicy.RUNTIME)
@Target({ElementType.METHOD})
public @interface MOCK {
String value() default "";
boolean enable() default true;
}
对retrofit对应Api.class 接口方法一通操作
@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
boolean isMockExist = method.isAnnotationPresent( MOCK.class );
//如果注解不存在 正常走流程
if (!isMockExist) {
return invoke( method, args );
}
MOCK mock = method.getAnnotation( MOCK.class );
//如果mock 设置为false 正常返回
if (!mock.enable()) {
return invoke( method, args );
}
String value = mock.value().trim();
//如果http开头 替换成url 正常请求
if (value.startsWith( "http" )) { //网络请求数据
preLoadServiceMethod( method, value );
return invoke( method, args );
} else if (value.endsWith( ".json" )) { //本地数据
String mockResponseJson = readAssets( value );
Object responseObj = retrofit.nextResponseBodyConverter( null, getReturnTye( method ), method.getDeclaredAnnotations() ).convert( ResponseBody.create( MediaType.parse( "application/json" ), mockResponseJson ) );
return (retrofit.nextCallAdapter( null, method.getGenericReturnType(), method.getAnnotations() )).adapt( new MockerCall( responseObj ) );
} else { //其他情况正常请求
return invoke( method, args );
}
}
private Object invoke(Method method, Object[] args) throws InvocationTargetException, IllegalAccessException {
if (args == null) {
return method.invoke( api );
} else {
return method.invoke( api, args );
}
}
3、修改网络请求地址
//修改url地址
private void preLoadServiceMethod(Method method, String relativeUrl) {
try {
Method loadServiceMethod = retrofit.getClass().getDeclaredMethod( "loadServiceMethod", Method.class );
loadServiceMethod.setAccessible( true );
//获得serviceMethod的值
Object serviceMethod = loadServiceMethod.invoke( retrofit, method );
//反射修改实体类中的值
fixRetrofit240( serviceMethod, relativeUrl );
fixRetrofit250( serviceMethod, relativeUrl );
} catch (Exception e) {
}
}
//eg : serviceMethod.relativeUrl = relativeUrl
//针对retrofit 2.4.0版本做适配
private void fixRetrofit240(Object serviceMethod, String relativeUrl) {
try {
Field relativeUrlField = serviceMethod.getClass().getDeclaredField( "relativeUrl" );
relativeUrlField.setAccessible( true );
relativeUrlField.set( serviceMethod, relativeUrl );
} catch (Exception e) {
}
}
//eg: serviceMethod.requestFactory.relativeUrl = relativeUrl
//针对retrofit 2.5.0版本做适配
private void fixRetrofit250(Object serviceMethod, String relativeUrl) {
try {
Field requestFactoryField = serviceMethod.getClass().getDeclaredField( "requestFactory" );
requestFactoryField.setAccessible( true );
Object requestFactory = requestFactoryField.get( serviceMethod );
Field relativeUrlField = requestFactory.getClass().getDeclaredField( "relativeUrl" );
relativeUrlField.setAccessible( true );
relativeUrlField.set( requestFactory, relativeUrl );
} catch (Exception e) {
}
}
4、特别感谢
首先特别感谢javalong,给retrofit-mock提供了好的思路
