OkHttpClient添加离线缓存

1.创建拦截器，用于判断什么时候读取缓存

Interceptor headerInterceptor = new Interceptor() {

            @Override
            public Response intercept(Chain chain) throws IOException {
                
                CacheControl.Builder cacheBuilder = new CacheControl.Builder();
                cacheBuilder.maxAge(0, TimeUnit.SECONDS);
                cacheBuilder.maxStale(365,TimeUnit.DAYS);
                CacheControl cacheControl = cacheBuilder.build();
                Request request = chain.request();
                if(!NetworkUtils.isConnected()){
                    request = request.newBuilder()
                            .cacheControl(cacheControl)
                            .build();
                }
                Response originalResponse = chain.proceed(request);
                if (NetworkUtils.isConnected()) {
                    int maxAge = 0; // read from cache
                    return originalResponse.newBuilder()
                            .removeHeader("Pragma")
                            .header("Cache-Control", "public ,max-age=" + maxAge)
                            .build();
                } else {
                    int maxStale = 60 * 60 * 24 * 28; // tolerate 4-weeks stale
                    return originalResponse.newBuilder()
                            .removeHeader("Pragma")
                            .header("Cache-Control", "public, only-if-cached, max-stale=" + maxStale)
                            .build();
                }
            }
        };

2.设定缓存文件的属性

        File cacheFile = new File(MyApp.getInstance().getContext().getCacheDir(), "cache");
        Cache cache = new Cache(cacheFile, 1024 * 1024 * 10); //10Mb

3.添加log打印（看需求）

 HttpLoggingInterceptor logInterceptor = new HttpLoggingInterceptor();
        logInterceptor.setLevel(HttpLoggingInterceptor.Level.BODY);

4.将以上的配置添加到OkHttpClient即可

OkHttpClient client = new OkHttpClient.Builder()
                .addInterceptor(headerInterceptor)
                .addInterceptor(logInterceptor)
                .cache(cache)
                .build();