Retortfit2

Retrofit是由Square公司出品的针对于Android和Java的类型安全的Http客户端，网络服务基于OkHttp 。 个人觉得更为准确的说法是，Retrofit是OkHttp的一个包装工具类，可以更加方便的调用Restful API。

Retrofit2 默认提供的Converter

Gson: com.squareup.retrofit2:converter-gson 
Jackson: com.squareup.retrofit2:converter-jackson 
Moshi: com.squareup.retrofit2:converter-moshi 
Protobuf: com.squareup.retrofit2:converter-protobuf 
Wire: com.squareup.retrofit2:converter-wire 

Simple XML: com.squareup.retrofit2:converter-simplexml 

Scalars (primitives, boxed, and String): com.squareup.retrofit2:converter-scalars

下面就来讲解如何扩展Converter

首先创建FastJsonConverterFactory 类，并继承Converter.Factory，重写其中的responseBodyConverter方法与requestBodyConverter方法。

import java.lang.annotation.Annotation;
import java.lang.reflect.Type;

import okhttp3.RequestBody;
import okhttp3.ResponseBody;
import retrofit2.Converter;
import retrofit2.Retrofit;

public class FastJsonConverterFactory extends Converter.Factory{

    public static FastJsonConverterFactory create() {
        return new FastJsonConverterFactory();
    }

    /**
    * 需要重写父类中responseBodyConverter，该方法用来转换服务器返回数据
    */
    @Override
    public Converter<ResponseBody, ?> responseBodyConverter(Type type, Annotation[] annotations, Retrofit retrofit) {
        return new FastJsonResponseBodyConverter<>(type);
    }

    /**
    * 需要重写父类中responseBodyConverter，该方法用来转换发送给服务器的数据
    */
    @Override
    public Converter<?, RequestBody> requestBodyConverter(Type type, Annotation[] parameterAnnotations, Annotation[] methodAnnotations, Retrofit retrofit) {
        return new FastJsonRequestBodyConverter<>();
    }

}

创建FastJsonResponseBodyConverter 类

import okhttp3.ResponseBody;
import okio.BufferedSource;
import okio.Okio;
import retrofit2.Converter;

public class FastJsonResponseBodyConverter<T> implements Converter<ResponseBody, T> {
    private final Type type;

    public FastJsonResponseBodyConverter(Type type) {
        this.type = type;
    }

    /*
    * 转换方法
    */
    @Override
    public T convert(ResponseBody value) throws IOException  {
        BufferedSource bufferedSource = Okio.buffer(value.source());
        String tempStr = bufferedSource.readUtf8();
        bufferedSource.close();
        return JSON.parseObject(tempStr, type);

    }
}

创建FastJsonRequestBodyConverter

import com.alibaba.fastjson.JSON;

import java.io.IOException;

import okhttp3.MediaType;
import okhttp3.RequestBody;
import retrofit2.Converter;

public class FastJsonRequestBodyConverter<T> implements Converter<T, RequestBody> {
    private static final MediaType MEDIA_TYPE = MediaType.parse("application/json; charset=UTF-8");

    @Override
    public RequestBody convert(T value) throws IOException {
        return RequestBody.create(MEDIA_TYPE, JSON.toJSONBytes(value));
    }
}

使用方法

 retrofit = new Retrofit.Builder()
                .baseUrl(BASE_URL)
                .client(CustomerOkHttpClient.getClient())
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                //在此处声明使用FastJsonConverter做为转换器
                .addConverterFactory(FastJsonConverterFactory.create())
                .build();

以上就是使用FastJson作为Retrofit2转换器的全部代码。