@POSTObservable<List<User>>method1(@Body Person rBody);

//将F类型的值转化为T类型的值
public interface Converter<F, T> {T convert(F value) throws IOException;abstract class Factory {//将API方法的返回类型从ResponseBody 转换为type，type是由CallAdapter 接口里面的responseType()函数返回的。public @Nullable Converter<ResponseBody, ?> responseBodyConverter(Type type,Annotation[] annotations, Retrofit retrofit) {return null;}//将API方法的输入参数类型从 type转换为ResponseBody ， 用于转换被注解@Body, @Part 和 @PartMap标记的类型public @Nullable Converter<?, RequestBody> requestBodyConverter(Type type,Annotation[] parameterAnnotations, Annotation[] methodAnnotations, Retrofit retrofit) {return null;}//将API方法的输入参数类型从 type 转换为String，用于转换被注解 @Header, @HeaderMap, @Path, @Query 和 @QueryMap 标记的类型public @Nullable Converter<?, String> stringConverter(Type type, Annotation[] annotations,Retrofit retrofit) {return null;}//下面是两个工具方法protected static Type getParameterUpperBound(int index, ParameterizedType type) {return Utils.getParameterUpperBound(index, type);}protected static Class<?> getRawType(Type type) {return Utils.getRawType(type);}}
}

final class BuiltInConverters extends Converter.Factory {//做的工作很简单，这里要求方法返回值类型type必须为ResponseBody或者Void，转化后的类型为ResponseBody。//返回相应的Converter实例，其他的类型都处理不了，直接返回null//当方法返回值类型type是ResponseBody时检查一下方法是否使用了@Streaming注解标识，如果没有标识则将数据全部读取到内存中，返回一个ResponseBody@Overridepublic Converter<ResponseBody, ?> responseBodyConverter(Type type, Annotation[] annotations, Retrofit retrofit) {if (type == ResponseBody.class) {return Utils.isAnnotationPresent(annotations, Streaming.class)? StreamingResponseBodyConverter.INSTANCE: BufferingResponseBodyConverter.INSTANCE;}if (type == Void.class) {return VoidResponseBodyConverter.INSTANCE;}return null;}//更简单，要求方法的请求参数type必须为RequestBody类型，得到的类型也是RequestBody，没有做任何类型转换，//返回相应的Converter实例，其他的类型都处理不了，直接返回null@Overridepublic Converter<?, RequestBody> requestBodyConverter(Type type, Annotation[] parameterAnnotations, Annotation[] methodAnnotations, Retrofit retrofit) {if (RequestBody.class.isAssignableFrom(Utils.getRawType(type))) {return RequestBodyConverter.INSTANCE;}return null;}//将object转成Stringstatic final class ToStringConverter implements Converter<Object, String> {static final ToStringConverter INSTANCE = new ToStringConverter();@Override public String convert(Object value) {return value.toString();}}...static final class VoidResponseBodyConverter implements Converter<ResponseBody, Void> {static final VoidResponseBodyConverter INSTANCE = new VoidResponseBodyConverter();@Override public Void convert(ResponseBody value) {value.close();return null;}}static final class RequestBodyConverter implements Converter<RequestBody, RequestBody> {static final RequestBodyConverter INSTANCE = new RequestBodyConverter();@Override public RequestBody convert(RequestBody value) {return value;}}//如果使用Streaming注解标记了方法，则使用这个转换器直接返回responseBody类型的数据，不读取到内存static final class StreamingResponseBodyConverterimplements Converter<ResponseBody, ResponseBody> {static final StreamingResponseBodyConverter INSTANCE = new StreamingResponseBodyConverter();@Override public ResponseBody convert(ResponseBody value) {return value;}}//如果不使用Streaming注解标记方法，则将返回值读取到内存中static final class BufferingResponseBodyConverterimplements Converter<ResponseBody, ResponseBody> {static final BufferingResponseBodyConverter INSTANCE = new BufferingResponseBodyConverter();@Override public ResponseBody convert(ResponseBody value) throws IOException {try {// Buffer the entire body to avoid future I/O.return Utils.buffer(value);} finally {value.close();}}}
}

public @Nullable Converter<?, String> stringConverter(Type type, Annotation[] annotations,Retrofit retrofit) {return null;}