retrofit封装请求头

    private RetrofitManager() {
        OkHttpClient.Builder builder = new OkHttpClient.Builder();
        builder.connectTimeout(15, TimeUnit.SECONDS);
        builder.readTimeout(15, TimeUnit.SECONDS);
        builder.writeTimeout(15, TimeUnit.SECONDS);
        builder.addInterceptor(new Interceptor() {
            @Override
            public Response intercept(Chain chain) throws IOException {
                Request request = chain.request();
                SharedPreferences preferences = MyApplication.getApplication().getSharedPreferences("User", Context.MODE_PRIVATE);
                String userId = preferences.getString("UserId", "");
                String sessionId = preferences.getString("SessionId", "");
                Request.Builder builder1 = request.newBuilder();
                builder1.method(request.method(),request.body());
                if(!TextUtils.isEmpty(userId)&&!TextUtils.isEmpty(sessionId)){
                    builder1.addHeader("userId",userId);
                    builder1.addHeader("sessionId",sessionId);
                }
                Request build = builder1.build();
                return chain.proceed(build);
            }
        });
        builder.retryOnConnectionFailure(true);
        OkHttpClient client = builder.build();

        Retrofit retrofit = new Retrofit.Builder()
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create())
                .baseUrl(BASE_URL)
                .client(client)
                .build();
        mBaseApis = retrofit.create(BaseApis.class);
    }