2.简单使用
fun provideRetrofit():Retrofit{
val clientBuild = OkHttpClient.Builder()
.connectTimeout(20000, TimeUnit.MILLISECONDS)
.readTimeout(20000, TimeUnit.MILLISECONDS)
.addInterceptor(HttpLoggingInterceptor().apply {
level = HttpLoggingInterceptor.Level.BODY
})
return Retrofit.Builder()
.baseUrl("https://api.github.com/")
.addConverterFactory(MoshiConverterFactory.create())
.client(clientBuild.build())
.build()
}
// @Singleton
// @Provides
fun provideUserService():TestApi = provideRetrofit().create(TestApi::class.java)
ApiService.provideUserService().searchRepos(1,1)
先看provideRetrofit().create(TestApi::class.java)
public <T> T create(final Class<T> service) {
validateServiceInterface(service);//步骤一
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 @Nullable Object invoke(Object proxy, Method method, @Nullable Object[] args)
throws Throwable {
// If the method is a method from Object then defer to normal invocation.
//如果是object类直接调用
if (method.getDeclaringClass() == Object.class) {
return method.invoke(this, args);
}
args = args != null ? args : emptyArgs;
// 步骤二平台判断
return platform.isDefaultMethod(method)
? platform.invokeDefaultMethod(method, service, proxy, args)
: loadServiceMethod(method).invoke(args);
}
});
}
先看步骤一
语法检查
private void validateServiceInterface(Class<?> service) {
if (!service.isInterface()) {
throw new IllegalArgumentException("API declarations must be interfaces.");
}
Deque<Class<?>> check = new ArrayDeque<>(1);
check.add(service);
while (!check.isEmpty()) {
Class<?> candidate = check.removeFirst();
if (candidate.getTypeParameters().length != 0) {
StringBuilder message =
new StringBuilder("Type parameters are unsupported on ").append(candidate.getName());
if (candidate != service) {
message.append(" which is an interface of ").append(service.getName());
}
throw new IllegalArgumentException(message.toString());
}
Collections.addAll(check, candidate.getInterfaces());
}
//validateEagerly是否提前解析方法注解标识跟下面流程一样
if (validateEagerly) {
Platform platform = Platform.get();
for (Method method : service.getDeclaredMethods()) {
if (!platform.isDefaultMethod(method) && !Modifier.isStatic(method.getModifiers())) {
loadServiceMethod(method);
}
}
}
}
步骤二查看loadServiceMethod(method).invoke(args)方法
ServiceMethod<?> loadServiceMethod(Method method) {
ServiceMethod<?> result = serviceMethodCache.get(method);
if (result != null) return result;
synchronized (serviceMethodCache) {
result = serviceMethodCache.get(method);
if (result == null) {
主要看这一步
result = ServiceMethod.parseAnnotations(this, method);
加入缓存
serviceMethodCache.put(method, result);
}
}
return result;
}
abstract class ServiceMethod<T> {
static <T> ServiceMethod<T> parseAnnotations(Retrofit retrofit, Method method) {
//把接口方法上的一些东西统一放进requestFactory里面
RequestFactory requestFactory = RequestFactory.parseAnnotations(retrofit, method);
Type returnType = method.getGenericReturnType();
if (Utils.hasUnresolvableType(returnType)) {
throw methodError(
method,
"Method return type must not include a type variable or wildcard: %s",
returnType);
}
if (returnType == void.class) {
throw methodError(method, "Service methods cannot return void.");
}
//看这句话
return HttpServiceMethod.parseAnnotations(retrofit, method, requestFactory);
}
abstract @Nullable T invoke(Object[] args);
}
static <ResponseT, ReturnT> HttpServiceMethod<ResponseT, ReturnT> parseAnnotations(
Retrofit retrofit, Method method, RequestFactory requestFactory) {
boolean isKotlinSuspendFunction = requestFactory.isKotlinSuspendFunction;
boolean continuationWantsResponse = false;
boolean continuationBodyNullable = false;
Annotation[] annotations = method.getAnnotations();
Type adapterType;
if (isKotlinSuspendFunction) {
Type[] parameterTypes = method.getGenericParameterTypes();
Type responseType =
Utils.getParameterLowerBound(
0, (ParameterizedType) parameterTypes[parameterTypes.length - 1]);
if (getRawType(responseType) == Response.class && responseType instanceof ParameterizedType) {
// Unwrap the actual body type from Response<T>.
responseType = Utils.getParameterUpperBound(0, (ParameterizedType) responseType);
continuationWantsResponse = true;
} else {
// TODO figure out if type is nullable or not
// Metadata metadata = method.getDeclaringClass().getAnnotation(Metadata.class)
// Find the entry for method
// Determine if return type is nullable or not
}
adapterType = new Utils.ParameterizedTypeImpl(null, Call.class, responseType);
annotations = SkipCallbackExecutorImpl.ensurePresent(annotations);
} else {
adapterType = method.getGenericReturnType();
}
//步骤一主要看这句创建一个calladapter
CallAdapter<ResponseT, ReturnT> callAdapter =
createCallAdapter(retrofit, method, adapterType, annotations);
Type responseType = callAdapter.responseType();
if (responseType == okhttp3.Response.class) {
throw methodError(
method,
"'"
+ getRawType(responseType).getName()
+ "' is not a valid response body type. Did you mean ResponseBody?");
}
if (responseType == Response.class) {
throw methodError(method, "Response must include generic type (e.g., Response<String>)");
}
// TODO support Unit for Kotlin?
if (requestFactory.httpMethod.equals("HEAD") && !Void.class.equals(responseType)) {
throw methodError(method, "HEAD method must use Void as response type.");
}
Converter<ResponseBody, ResponseT> responseConverter =
createResponseConverter(retrofit, method, responseType);
okhttp3.Call.Factory callFactory = retrofit.callFactory;
if (!isKotlinSuspendFunction) {
//新建个CallAdapted
return new CallAdapted<>(requestFactory, callFactory, responseConverter, callAdapter);
} else if (continuationWantsResponse) {
//noinspection unchecked Kotlin compiler guarantees ReturnT to be Object.
return (HttpServiceMethod<ResponseT, ReturnT>)
new SuspendForResponse<>(
requestFactory,
callFactory,
responseConverter,
(CallAdapter<ResponseT, Call<ResponseT>>) callAdapter);
} else {
//noinspection unchecked Kotlin compiler guarantees ReturnT to be Object.
return (HttpServiceMethod<ResponseT, ReturnT>)
new SuspendForBody<>(
requestFactory,
callFactory,
responseConverter,
(CallAdapter<ResponseT, Call<ResponseT>>) callAdapter,
continuationBodyNullable);
}
}
步骤一，创建一个calladapter
点进去
public CallAdapter<?, ?> nextCallAdapter(
@Nullable CallAdapter.Factory skipPast, Type returnType, Annotation[] annotations) {
Objects.requireNonNull(returnType, "returnType == null");
Objects.requireNonNull(annotations, "annotations == null");
int start = callAdapterFactories.indexOf(skipPast) + 1;
for (int i = start, count = callAdapterFactories.size(); i < count; i++) {
CallAdapter<?, ?> adapter = callAdapterFactories.get(i).get(returnType, annotations, this);
if (adapter != null) {
return adapter;
}
}
可以看出是通过callAdapterFactories来的，这个callAdapterFactories 是通过 Retrofit 类初始化来的查看构造方法
// Make a defensive copy of the adapters and add the default Call adapter.
List<CallAdapter.Factory> callAdapterFactories = new ArrayList<>(this.callAdapterFactories);
callAdapterFactories.addAll(platform.defaultCallAdapterFactories(callbackExecutor));
查看platform.defaultCallAdapterFactories(callbackExecutor)
final class DefaultCallAdapterFactory extends CallAdapter.Factory {
private final @Nullable Executor callbackExecutor;
DefaultCallAdapterFactory(@Nullable Executor callbackExecutor) {
this.callbackExecutor = callbackExecutor;
}
@Override
public @Nullable CallAdapter<?, ?> get(
Type returnType, Annotation[] annotations, Retrofit retrofit) {
if (getRawType(returnType) != Call.class) {
return null;
}
if (!(returnType instanceof ParameterizedType)) {
throw new IllegalArgumentException(
"Call return type must be parameterized as Call<Foo> or Call<? extends Foo>");
}
final Type responseType = Utils.getParameterUpperBound(0, (ParameterizedType) returnType);
final Executor executor =
Utils.isAnnotationPresent(annotations, SkipCallbackExecutor.class)
? null
: callbackExecutor;
return new CallAdapter<Object, Call<?>>() {
@Override
public Type responseType() {
return responseType;
}
@Override
//重重重重点adapt
public Call<Object> adapt(Call<Object> call) {
return executor == null ? call : new ExecutorCallbackCall<>(executor, call);
}
};
}
所以说loadServiceMethod(method)方法将就是创建个CallAdapted，接下来看.invoke(args)，loadServiceMethod返回的是ServiceMethod，是个抽象类，所以要看具体实现类，HttpServiceMethod里面的
@Override
final @Nullable ReturnT invoke(Object[] args) {
Call<ResponseT> call = new OkHttpCall<>(requestFactory, args, callFactory, responseConverter);
return adapt(call, args);
}
一步步走
static final class CallAdapted<ResponseT, ReturnT> extends HttpServiceMethod<ResponseT, ReturnT> {
private final CallAdapter<ResponseT, ReturnT> callAdapter;
CallAdapted(
RequestFactory requestFactory,
okhttp3.Call.Factory callFactory,
Converter<ResponseBody, ResponseT> responseConverter,
CallAdapter<ResponseT, ReturnT> callAdapter) {
super(requestFactory, callFactory, responseConverter);
this.callAdapter = callAdapter;//重点
}
@Override
protected ReturnT adapt(Call<ResponseT> call, Object[] args) {
return callAdapter.adapt(call);//重点
}
}
最后看到的是执行了CallAdapted的adapt方法
callAdapter.adapt(call)的callAdapter就是上文createCallAdapter(retrofit, method, adapterType, annotations)创建出来的，所以callAdapter.adapt(call)最后调用的就是ExecutorCallbackCall<>(executor, call)
方法
接下来看ExecutorCallbackCall
static final class ExecutorCallbackCall<T> implements Call<T> {
final Executor callbackExecutor;
final Call<T> delegate;
ExecutorCallbackCall(Executor callbackExecutor, Call<T> delegate) {
this.callbackExecutor = callbackExecutor;
this.delegate = delegate;
}
@Override
public void enqueue(final Callback<T> callback) {
Objects.requireNonNull(callback, "callback == null");
delegate.enqueue(
new Callback<T>() {
@Override
public void onResponse(Call<T> call, final Response<T> response) {
callbackExecutor.execute(
() -> {
if (delegate.isCanceled()) {
// Emulate OkHttp's behavior of throwing/delivering an IOException on
// cancellation.
callback.onFailure(ExecutorCallbackCall.this, new IOException("Canceled"));
} else {
callback.onResponse(ExecutorCallbackCall.this, response);
}
});
}
@Override
public void onFailure(Call<T> call, final Throwable t) {
callbackExecutor.execute(() -> callback.onFailure(ExecutorCallbackCall.this, t));
}
});
}
是切换到主线程执行回调出去
接下来看okhttp怎么和Retrofit结合的delegate.enqueue回溯，看下delegate哪里来的
@Override
public @Nullable CallAdapter<?, ?> get(
Type returnType, Annotation[] annotations, Retrofit retrofit) {
if (getRawType(returnType) != Call.class) {
return null;
}
if (!(returnType instanceof ParameterizedType)) {
throw new IllegalArgumentException(
"Call return type must be parameterized as Call<Foo> or Call<? extends Foo>");
}
final Type responseType = Utils.getParameterUpperBound(0, (ParameterizedType) returnType);
final Executor executor =
Utils.isAnnotationPresent(annotations, SkipCallbackExecutor.class)
? null
: callbackExecutor;
return new CallAdapter<Object, Call<?>>() {
@Override
public Type responseType() {
return responseType;
}
主要看这句话，
@Override
public Call<Object> adapt(Call<Object> call) {
return executor == null ? call : new ExecutorCallbackCall<>(executor, call);
}
};
往回走
@Override
final @Nullable ReturnT invoke(Object[] args) {
//这里
Call<ResponseT> call = new OkHttpCall<>(requestFactory, args, callFactory, responseConverter);
return adapt(call, args);
}
protected abstract @Nullable ReturnT adapt(Call<ResponseT> call, Object[] args);
static final class CallAdapted<ResponseT, ReturnT> extends HttpServiceMethod<ResponseT, ReturnT> {
private final CallAdapter<ResponseT, ReturnT> callAdapter;
CallAdapted(
RequestFactory requestFactory,
okhttp3.Call.Factory callFactory,
Converter<ResponseBody, ResponseT> responseConverter,
CallAdapter<ResponseT, ReturnT> callAdapter) {
super(requestFactory, callFactory, responseConverter);
this.callAdapter = callAdapter;
}
@Override
protected ReturnT adapt(Call<ResponseT> call, Object[] args) {
//这里
return callAdapter.adapt(call);
}
}
看到这句话
Call<ResponseT> call = new OkHttpCall<>(requestFactory, args, callFactory, responseConverter);
创建了一个okhttpcall
在看里面的enqueue方法
@Override
public void enqueue(final Callback<T> callback) {
Objects.requireNonNull(callback, "callback == null");
okhttp3.Call call;
Throwable failure;
synchronized (this) {
if (executed) throw new IllegalStateException("Already executed.");
executed = true;
call = rawCall;
failure = creationFailure;
if (call == null && failure == null) {
try {
call = rawCall = createRawCall();//这句话等会看
} catch (Throwable t) {
throwIfFatal(t);
failure = creationFailure = t;
}
}
}
if (failure != null) {
callback.onFailure(this, failure);
return;
}
if (canceled) {
call.cancel();
}
call.enqueue(
new okhttp3.Callback() {
@Override
public void onResponse(okhttp3.Call call, okhttp3.Response rawResponse) {
Response<T> response;
try {
response = parseResponse(rawResponse);
} catch (Throwable e) {
throwIfFatal(e);
callFailure(e);
return;
}
try {
callback.onResponse(OkHttpCall.this, response);
} catch (Throwable t) {
throwIfFatal(t);
t.printStackTrace(); // TODO this is not great
}
}
@Override
public void onFailure(okhttp3.Call call, IOException e) {
callFailure(e);
}
private void callFailure(Throwable e) {
try {
callback.onFailure(OkHttpCall.this, e);
} catch (Throwable t) {
throwIfFatal(t);
t.printStackTrace(); // TODO this is not great
}
}
});
}
可以得知通过创建createRawCall生成okhttpcall然后调用enqueue切换到自子线程，再通过Retrofit的callback切换到主线程
接下来只有两个问题createRawCall怎么生成的，Retrofit的callback怎么切换的
先看createRawCall
private okhttp3.Call createRawCall() throws IOException {
okhttp3.Call call = callFactory.newCall(requestFactory.create(args));
if (call == null) {
throw new NullPointerException("Call.Factory returned null.");
}
return call;
}
查看他的callfactory和requestfactory哪里来的
abstract class HttpServiceMethod<ResponseT, ReturnT> extends ServiceMethod<ReturnT> {
/**
* Inspects the annotations on an interface method to construct a reusable service method that
* speaks HTTP. This requires potentially-expensive reflection so it is best to build each service
* method only once and reuse it.
*/
static <ResponseT, ReturnT> HttpServiceMethod<ResponseT, ReturnT>
//RequestFactory的由来
parseAnnotations(
Retrofit retrofit, Method method, RequestFactory requestFactory) {
boolean isKotlinSuspendFunction = requestFactory.isKotlinSuspendFunction;
boolean continuationWantsResponse = false;
boolean continuationBodyNullable = false;
Annotation[] annotations = method.getAnnotations();
Type adapterType;
if (isKotlinSuspendFunction) {
Type[] parameterTypes = method.getGenericParameterTypes();
Type responseType =
Utils.getParameterLowerBound(
0, (ParameterizedType) parameterTypes[parameterTypes.length - 1]);
if (getRawType(responseType) == Response.class && responseType instanceof ParameterizedType) {
// Unwrap the actual body type from Response<T>.
responseType = Utils.getParameterUpperBound(0, (ParameterizedType) responseType);
continuationWantsResponse = true;
} else {
// TODO figure out if type is nullable or not
// Metadata metadata = method.getDeclaringClass().getAnnotation(Metadata.class)
// Find the entry for method
// Determine if return type is nullable or not
}
adapterType = new Utils.ParameterizedTypeImpl(null, Call.class, responseType);
annotations = SkipCallbackExecutorImpl.ensurePresent(annotations);
} else {
adapterType = method.getGenericReturnType();
}
CallAdapter<ResponseT, ReturnT> callAdapter =
createCallAdapter(retrofit, method, adapterType, annotations);
Type responseType = callAdapter.responseType();
if (responseType == okhttp3.Response.class) {
throw methodError(
method,
"'"
+ getRawType(responseType).getName()
+ "' is not a valid response body type. Did you mean ResponseBody?");
}
if (responseType == Response.class) {
throw methodError(method, "Response must include generic type (e.g., Response<String>)");
}
// TODO support Unit for Kotlin?
if (requestFactory.httpMethod.equals("HEAD") && !Void.class.equals(responseType)) {
throw methodError(method, "HEAD method must use Void as response type.");
}
Converter<ResponseBody, ResponseT> responseConverter =
createResponseConverter(retrofit, method, responseType);
//callFactory的由来
okhttp3.Call.Factory callFactory = retrofit.callFactory;
if (!isKotlinSuspendFunction) {
return new CallAdapted<>(requestFactory, callFactory, responseConverter, callAdapter);
这里先看callFactory
public Retrofit build() {
if (baseUrl == null) {
throw new IllegalStateException("Base URL required.");
}
okhttp3.Call.Factory callFactory = this.callFactory;
if (callFactory == null) {
callFactory = new OkHttpClient();
}
在build里面初始化
然后再看RequestFactory查看HttpServiceMethod他的父类
abstract class ServiceMethod<T> {
static <T> ServiceMethod<T> parseAnnotations(Retrofit retrofit, Method method) {
主要看这句话
RequestFactory requestFactory = RequestFactory.parseAnnotations(retrofit, method);
Type returnType = method.getGenericReturnType();
if (Utils.hasUnresolvableType(returnType)) {
throw methodError(
method,
"Method return type must not include a type variable or wildcard: %s",
returnType);
}
if (returnType == void.class) {
throw methodError(method, "Service methods cannot return void.");
}
return HttpServiceMethod.parseAnnotations(retrofit, method, requestFactory);
}
abstract @Nullable T invoke(Object[] args);
}
跳转到 static RequestFactory parseAnnotations(Retrofit retrofit, Method method) {
return new Builder(retrofit, method).build();
}
查看build
RequestFactory build() {
for (Annotation annotation : methodAnnotations) {
parseMethodAnnotation(annotation);
}
if (httpMethod == null) {
throw methodError(method, "HTTP method annotation is required (e.g., @GET, @POST, etc.).");
}
if (!hasBody) {
if (isMultipart) {
throw methodError(
method,
"Multipart can only be specified on HTTP methods with request body (e.g., @POST).");
}
if (isFormEncoded) {
throw methodError(
method,
"FormUrlEncoded can only be specified on HTTP methods with "
+ "request body (e.g., @POST).");
}
}
int parameterCount = parameterAnnotationsArray.length;
parameterHandlers = new ParameterHandler<?>[parameterCount];
for (int p = 0, lastParameter = parameterCount - 1; p < parameterCount; p++) {
parameterHandlers[p] =
parseParameter(p, parameterTypes[p], parameterAnnotationsArray[p], p == lastParameter);
}
if (relativeUrl == null && !gotUrl) {
throw methodError(method, "Missing either @%s URL or @Url parameter.", httpMethod);
}
if (!isFormEncoded && !isMultipart && !hasBody && gotBody) {
throw methodError(method, "Non-body HTTP method cannot contain @Body.");
}
if (isFormEncoded && !gotField) {
throw methodError(method, "Form-encoded method must contain at least one @Field.");
}
if (isMultipart && !gotPart) {
throw methodError(method, "Multipart method must contain at least one @Part.");
}
return new RequestFactory(this);
}
解析注解返回 new RequestFactory(this)
上面说okhttp3.Call call = callFactory.newCall(requestFactory.create(args));
然后再查看creat方法
okhttp3.Request create(Object[] args) throws IOException {
@SuppressWarnings("unchecked") // It is an error to invoke a method with the wrong arg types.
ParameterHandler<Object>[] handlers = (ParameterHandler<Object>[]) parameterHandlers;
int argumentCount = args.length;
if (argumentCount != handlers.length) {
throw new IllegalArgumentException(
"Argument count ("
+ argumentCount
+ ") doesn't match expected count ("
+ handlers.length
+ ")");
}
RequestBuilder requestBuilder =
new RequestBuilder(
httpMethod,
baseUrl,
relativeUrl,
headers,
contentType,
hasBody,
isFormEncoded,
isMultipart);
if (isKotlinSuspendFunction) {
// The Continuation is the last parameter and the handlers array contains null at that index.
argumentCount--;
}
List<Object> argumentList = new ArrayList<>(argumentCount);
for (int p = 0; p < argumentCount; p++) {
argumentList.add(args[p]);
handlers[p].apply(requestBuilder, args[p]);
}
return requestBuilder.get().tag(Invocation.class, new Invocation(method, argumentList)).build();
}
就是给okhttp一些信息参数什么的
再看Retrofit的callback怎么切换的，上文有说
call.enqueue(
new okhttp3.Callback() {
@Override
public void onResponse(okhttp3.Call call, okhttp3.Response rawResponse) {
Response<T> response;
try {
response = parseResponse(rawResponse);
} catch (Throwable e) {
throwIfFatal(e);
callFailure(e);
return;
}
try {
callback.onResponse(OkHttpCall.this, response);
} catch (Throwable t) {
throwIfFatal(t);
t.printStackTrace(); // TODO this is not great
}
}
@Override
public void onFailure(okhttp3.Call call, IOException e) {
callFailure(e);
}
private void callFailure(Throwable e) {
try {
callback.onFailure(OkHttpCall.this, e);
} catch (Throwable t) {
throwIfFatal(t);
t.printStackTrace(); // TODO this is not great
}
}
});
enqueue主线程切换到子线程。然后调用callback方法看下callback是什么东西
因为callback是ExecutorCallbackCall传入的
又是由DefaultCallAdapterFactory初始化的
然后一顿跑
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<CallAdapter.Factory> callAdapterFactories = new ArrayList<>(this.callAdapterFactories);
callAdapterFactories.addAll(platform.defaultCallAdapterFactories(callbackExecutor));
到这里来了然后看下
callbackExecutor = platform.defaultCallbackExecutor();
发现return为null
@Nullable
Executor defaultCallbackExecutor() {
return null;
}
因为有很多平台所以要看android的
static final class Android extends Platform {
Android() {
super(Build.VERSION.SDK_INT >= 24);
}
@Override
public Executor defaultCallbackExecutor() {
return new MainThreadExecutor();
}
static final class MainThreadExecutor implements Executor {
private final Handler handler = new Handler(Looper.getMainLooper());
@Override
public void execute(Runnable r) {
handler.post(r);
}
}
}
可以发现是由handler切换线程的
流程总结
1.通过调用create方法动态代理生成loadServiceMethod(method).invoke()
- loadServiceMethod里面调用ServiceMethod.parseAnnotations,parseAnnotations 调用了 HttpServiceMethod.parseAnnotations还通过其代码分析出返回了一个 CallAdapted 对象。由此分析出第一步中调用的 invoke 方法即为 CallAdapted 的 invoke
3.CallAdapted 的 invoke 方法调用了其内部变量 callAdapter 的 adapte 方法，
4.callAdapter 是通过内部变量 callAdapterFactories 容器中取出并且调用其 get 方法获得。
5.Retrofit 的 build 方法中发现 callAdapterFactories 默认会添加一个 DefaultCallAdapterFactory 类型的元素，其 get 方法实现返回了一个CallAdapter 对象，其 adapt 方法返回了一个 ExecutorCallbackCall 对象。由此得出示例代码中执行请求的enqueue方法最终会调用到 ExecutorCallbackCall 对象的 enqueue 方法。
参数怎么传递
- RequestFactory.parseAnnotations(retrofit, method)的时候解析注解参数并传入并在执行creat的时候返回okhttp3.Request create
线程怎么切换
2.先通过okhttp.enqueue主线程切换到子线程，再通过callbackExecutor，由子线程再到主线程
动态代理外观装饰者策略设计模式
