public interface Api { @POST("product/getProductDetail") Observable<Goods_Bean> getGoods(@QueryMap Map<String,String> map); @POST("product/addCart") Observable<Add_Bean> getAdd(@QueryMap Map<String,String> map); @POST("product/getCarts") Observable<Query_bean> getShopCar(@QueryMap Map<String,String> map);}

/** * 自定義攔截器.使用的是okhttp來定義的攔截器 */public class MyInterceptor implements Interceptor { @Override public Response intercept(Chain chain) throws IOException { Request request = chain.request(); HttpUrl httpUrl = request  .url()  .newBuilder()  .addQueryParameter("source", "android")  .build(); Request requestNew = request  .newBuilder()  .url(httpUrl)  .build(); return chain.proceed(requestNew); }}

public class RetrofitUtil {  public static volatile Retrofit instance;  public static Retrofit getInstance(String baseUrl){  if (instance==null){   synchronized (RetrofitUtil.class){   //攔截器   OkHttpClient client = new OkHttpClient.Builder()    .addInterceptor(new MyInterceptor())    .build();   //創建retrofit對象   instance = new Retrofit.Builder()    .baseUrl(baseUrl)    .client(client)    .addConverterFactory(GsonConverterFactory.create())    .addCallAdapterFactory(RxJava2CallAdapterFactory.create())    .build();   }  }  return instance;  } }