public class RetrofitUtils {
    private static volatile RetrofitUtils instance;
    private final Retrofit retrofit;

    private RetrofitUtils(){
        OkHttpClient client = new OkHttpClient.Builder()
                .addInterceptor(new Logger()).build();

        retrofit = new Retrofit.Builder()
                .client(client)
                .addCallAdapterFactory(RxJava2CallAdapterFactory.create
 
())
                .addConverterFactory(GsonConverterFactory.create())
                .baseUrl("http://120.27.23.105/")
                .build();
    }

    public static RetrofitUtils getInstance(){
        if(instance==null){
            synchronized (RetrofitUtils.class){
                if(instance
 
==null){
                    instance=new RetrofitUtils();
                }
            }
        }
        return instance;
    }

    public ApiService getApiService(){
        ApiService apiService = retrofit.create(ApiService.class);
        return apiService;
    }

    class Logger implements 
 
Interceptor {
        @Override
public Response intercept(Chain chain) throws IOException {
            Request original = chain.request();
            HttpUrl url=original.url().newBuilder()
                    .addQueryParameter("source","android")
                    .build();
            //新增請求頭
Request request = original.newBuilder()
                    .url(url)
                    .build();
            return chain.proceed(request);
        }
    }
}