Retorfit2和OkHttp3缓存

需求如下:当用户在有网络的情况下,设置一个”缓冲时间”,比如在请求了一次网络数据之后,接下来60s内进行网络请求其实是拿的缓存,这样做可以减少服务器负担,节约流量.
当无网络时,用缓存读取数据,数据默认保存2周.这样就可以进行离线阅读.

1.首先来配置拦截器

配置好时间等属性,再结合判断是否有网络来进行设置

public class RewriteCacheControlInterceptor implements Interceptor {    private Context mContext;    /**     * 无网络,设缓存有效期为两周     */    private static final long CACHE_STALE_SEC = 60 * 60 * 24 * 14;    /**     * 有网 缓存60s     */    private static final long MAX_AGE = 60;    public RewriteCacheControlInterceptor(Context context) {        this.mContext = context;    }    @Override    public Response intercept(Chain chain) throws IOException {        Request request = chain.request();        String cacheControl = request.cacheControl().toString();        if (!DevicesUtils.hasNetworkConnected(mContext)) {            request = request.newBuilder()                    .cacheControl(TextUtils.isEmpty(cacheControl) ? CacheControl.FORCE_CACHE :                            CacheControl.FORCE_NETWORK)                    .build();        }        Response originalResponse = chain.proceed(request);        if (DevicesUtils.hasNetworkConnected(mContext)) {            //有网的时候连接服务器请求,缓存60s            return originalResponse.newBuilder()                    .header("Cache-Control", "public, max-age=" + MAX_AGE)                    .removeHeader("Pragma")                    .build();        } else {            //网络断开时读取缓存            return originalResponse.newBuilder()                    .header("Cache-Control", "public, only-if-cached, max-stale=" + CACHE_STALE_SEC)                    .removeHeader("Pragma")                    .build();        }    }}

2. 初始化OkHttp3

将拦截器设置进去即可.

/*** 初始化OkHttp*/public static void initOkHttp(Context context) {    //拦截器    RewriteCacheControlInterceptor mRewriteCacheControlInterceptor = new            RewriteCacheControlInterceptor(context);    //缓存文件    File cacheFile = context.getCacheDir();    //设置缓存大小    Cache cache = new Cache(cacheFile, MAX_CACHE_SIZE);    if (cacheFile != null) {        okHttpClient = new OkHttpClient.Builder()                //超时设置                .readTimeout(READ_TIME_OUT, TimeUnit.SECONDS)                .connectTimeout(CONNECT_TIME_OUT, TimeUnit.SECONDS)                //错误重连                .retryOnConnectionFailure(true)                //拦截器                .addNetworkInterceptor(mRewriteCacheControlInterceptor)                .addInterceptor(mRewriteCacheControlInterceptor)                //缓存                .cache(cache)                .build();    } else {        okHttpClient = new OkHttpClient.Builder().build();    }}