Retrofit2学习之二：Retrofit 转换器

Converter简介

Retrofit转换器可以实现响应对象 ResponseBody 至 JavaBean对象的转换。

Wiki：https://github.com/square/retrofit/wiki/Converters

Retrofit2 Converters

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 Framework - com.squareup.retrofit2:converter-simpleframework
Scalars - com.squareup.retrofit2:converter-scalars

- LoganSquare - com.github.aurae.retrofit2:converter-logansquare
- FastJson - org.ligboy.retrofit2:converter-fastjson or org.ligboy.retrofit2:converter-fastjson-android

Converter使用

以Gson转换器为例，实现JSON响应体和JavaBean对象转换。

配置gradle

在app模块的build.gradle配置

compile 'com.squareup.retrofit2:retrofit:2.1.0'
compile 'com.squareup.retrofit2:converter-gson:2.1.0'

创建业务请求接口

public interface Api {

    @GET("user/info?id=1")
    Call<User> getUserInfo();

}

创建一个Retrofit的实例，并配置转换器，然后利用Retrofit实例创建接口对象和调用接口方法

public void getRequestConverter(View view) {
    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(SERVER_ADDRESS)
            .addConverterFactory(GsonConverterFactory.create())  //配置Gson转换器，调用Gson库解析json返回值
            .build();

    Api api = retrofit.create(Api.class);

    api.getUserInfo().enqueue(new Callback<User>() {
        @Override
        public void onResponse(Call<User> call, Response<User> response) {
            //在UI主线程运行
            if (response.isSuccessful()) {
                Log.i(TAG, "返回成功");
                User user = response.body();
                if (user != null) {
                    Toast.makeText(MainActivity.this, user.getUsername(), Toast.LENGTH_SHORT).show();
                }
            }
        }

        @Override
        public void onFailure(Call<User> call, Throwable t) {
            Log.i(TAG, "请求失败: " + t.getLocalizedMessage());
        }
    });
}