File httpCacheDirectory = new File(Environment.getExternalStorageDirectory(), "HttpCache");//这里为了方便直接把文件放在了SD卡根目录的HttpCache中，一般放在context.getCacheDir()中
int cacheSize = 10 * 1024 * 1024;//设置缓存文件大小为10M
Cache cache = new Cache(httpCacheDirectory, cacheSize);
httpClient = new OkHttpClient.Builder().connectTimeout(10, TimeUnit.SECONDS)//设置连接超时.readTimeout(10, TimeUnit.SECONDS)//读取超时.writeTimeout(10, TimeUnit.SECONDS)//写入超时.addNetworkInterceptor(REWRITE_CACHE_CONTROL_INTERCEPTOR)//添加自定义缓存拦截器（后面讲解），注意这里需要使用.addNetworkInterceptor.cache(cache)//把缓存添加进来.build();

retrofit = new Retrofit.Builder().baseUrl(baseUrl).client(httpClient)//把OkHttpClient添加进来
                .addConverterFactory(GsonConverterFactory.create()).build();

 static Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = new Interceptor() {@Overridepublic Response intercept(Chain chain) throws IOException {Request request = chain.request();//网上很多示例代码都对在request请求前对其进行无网的判断，其实无需判断，无网自动访问缓存
//            if(!NetworkUtil.getInstance().isConnected()){
//                request = request.newBuilder()
//                        .cacheControl(CacheControl.FORCE_CACHE)//只访问缓存
//                        .build();
//            }Response response = chain.proceed(request);if (NetworkUtil.getInstance().isConnected()) {int maxAge = 60;//缓存失效时间，单位为秒return response.newBuilder().removeHeader("Pragma")//清除头信息，因为服务器如果不支持，会返回一些干扰信息，不清除下面无法生效.header("Cache-Control", "public ,max-age=" + maxAge).build();} else {//这段代码设置无效
//                int maxStale = 60 * 60 * 24 * 28; // 无网络时，设置超时为4周
//                return response.newBuilder()
//                        .header("Cache-Control", "public, only-if-cached, max-stale=" + maxStale)
//                        .removeHeader("Pragma")
//                        .build();
            }return response;}};

    @Headers("Cache-Control:public ,max-age=60")@GET("getBusiness.action")//商店信息Call<RestaurantInfoModel> getRestaurantInfo(@Query("userId") String userId,@Query("businessId") String businessId);

    static Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = new Interceptor() {@Overridepublic Response intercept(Chain chain) throws IOException {Request request = chain.request();Response response = chain.proceed(request);if (NetworkUtil.getInstance().isConnected()) {//获取头部信息String cacheControl =request.cacheControl().toString();return response.newBuilder().removeHeader("Pragma")//清除头信息，因为服务器如果不支持，会返回一些干扰信息，不清除下面无法生效.header("Cache-Control", cacheControl).build();}return response;}};

/*** 简单封装的Retroit初始化类*/
public class initRetrofit {private static String baseUrl = "http://202.171.212.154:8080/hh/";private static OkHttpClient httpClient;private static Retrofit retrofit;public static Retrofit initRetrofit() {//缓存路径和大小File httpCacheDirectory = new File(Environment.getExternalStorageDirectory(), "HttpCache");int cacheSize = 10 * 1024 * 1024;Cache cache = new Cache(httpCacheDirectory, cacheSize);//日志拦截器HttpLoggingInterceptor interceptor = new HttpLoggingInterceptor();interceptor.setLevel(HttpLoggingInterceptor.Level.BODY);httpClient = new OkHttpClient.Builder().connectTimeout(10, TimeUnit.SECONDS)//设置连接超时.readTimeout(10, TimeUnit.SECONDS)//读取超时.writeTimeout(10, TimeUnit.SECONDS)//写入超时.addInterceptor(interceptor)//添加日志拦截器.addNetworkInterceptor(REWRITE_CACHE_CONTROL_INTERCEPTOR)//添加缓存拦截器.cache(cache)//把缓存添加进来
                .build();retrofit = new Retrofit.Builder().baseUrl(baseUrl).client(httpClient).addConverterFactory(GsonConverterFactory.create()).build();return retrofit;}public static RetrofitAPI getService() {return initRetrofit().create(RetrofitAPI.class);}//    //缓存拦截器，不同接口不同缓存
//    static Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = new Interceptor() {
//        @Override
//        public Response intercept(Chain chain) throws IOException {
//
//            Request request = chain.request();
//            Response response = chain.proceed(request);
//
//            if (NetworkUtil.getInstance().isConnected()) {
//                String cacheControl =request.cacheControl().toString();
//                return response.newBuilder()
//                        .removeHeader("Pragma")//清除头信息，因为服务器如果不支持，会返回一些干扰信息，不清除下面无法生效
//                        .header("Cache-Control", cacheControl)
//                        .build();
//            }
//            return response;
//        }
//    };//缓存拦截器，统一缓存60sstatic Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = new Interceptor() {@Overridepublic Response intercept(Chain chain) throws IOException {Request request = chain.request();Response response = chain.proceed(request);if (NetworkUtil.getInstance().isConnected()) {int maxAge = 60*60*24*2;//缓存失效时间，单位为秒return response.newBuilder().removeHeader("Pragma")//清除头信息，因为服务器如果不支持，会返回一些干扰信息，不清除下面无法生效.header("Cache-Control", "public ,max-age=" + maxAge).build();}return response;}};
}