首先需要新增一些依賴

    compile 'io.reactivex:rxandroid:1.2.0'
    compile 'io.reactivex:rxjava:1.1.5'
    compile 'com.google.code.gson:gson:2.4'
    compile 'com.squareup.retrofit2:retrofit:2.0.2'
    compile 'com.squareup.retrofit2:converter-gson:2.0.2'
    compile 'com.squareup.retrofit2:converter-jackson:2.0.0'
 

    compile 'com.squareup.retrofit2:adapter-rxjava:2.0.2'
    compile 'com.squareup.okhttp3:okhttp:3.0.1'
    compile 'com.squareup.okhttp3:logging-interceptor:3.0.1'
    compile 'com.squareup.okio:okio:1.6.0'

然後自定義封裝一個網路訪問的類

public class NetManager {

    private NetService mNetService;
    /**
     * 設快取有效期為兩天
     */
 

    private static final long CACHE_STALE_SEC = 60 * 60 * 24 * 2;

    /**
     * 查詢快取的Cache-Control設定，為if-only-cache時只查詢快取而不會請求伺服器，max-stale可以配合設定快取失效時間
     * max-stale 指示客戶機可以接收超出超時期間的響應訊息。如果指定max-stale訊息的值，那麼客戶機可接收超出超時期指定值之內的響應訊息。
     */
    private static final String CACHE_CONTROL_CACHE = "only-if-cached, max-stale="
 
 + CACHE_STALE_SEC;

    /**
     * 查詢網路的Cache-Control設定，頭部Cache-Control設為max-age=0
     * (假如請求了伺服器並在a時刻返回響應結果，則在max-age規定的秒數內，瀏覽器將不會發送對應的請求到伺服器，資料由快取直接返回)時則不會使用快取而請求伺服器
     */
    private static final String CACHE_CONTROL_AGE = "max-age=0";

    private static volatile OkHttpClient sOkHttpClient;

    private static SparseArray<NetManager> sRetrofitManager = new SparseArray<>(HostType.TYPE_COUNT);

    public NetManager(int hostType){
        Retrofit retrofit = new Retrofit.Builder().baseUrl(URLConstants.getHost(hostType))
                .client(getOkHttpClient()).addConverterFactory(GsonConverterFactory.create())
                .addCallAdapterFactory(RxJavaCallAdapterFactory.create()).build();
        mNetService=retrofit.create(NetService.class);//生成不同的service
    }

    private OkHttpClient getOkHttpClient() {
        if (sOkHttpClient == null) {
            synchronized (NetManager.class) {
                Cache cache = new Cache(new File(App.getAppContext().getCacheDir(), "HttpCache"),
                        1024 * 1024 * 100);
                if (sOkHttpClient == null) {
                    sOkHttpClient = new OkHttpClient.Builder().cache(cache)
                            .connectTimeout(6, TimeUnit.SECONDS)
                            .readTimeout(6, TimeUnit.SECONDS)
                            .writeTimeout(6, TimeUnit.SECONDS)
                            .addInterceptor(mRewriteCacheControlInterceptor)
                            .addNetworkInterceptor(mRewriteCacheControlInterceptor)
                            .addInterceptor(mLoggingInterceptor).build();
                }
            }
        }
        return sOkHttpClient;
    }

    /**
     * 雲端響應頭攔截器，用來配置快取策略
     * Dangerous interceptor that rewrites the server's cache-control header.
     */
    private final Interceptor mRewriteCacheControlInterceptor = new Interceptor() {
        @Override
        public Response intercept(Chain chain) throws IOException {
            Request request = chain.request();
            if (!NetUtil.isNetworkAvailable()) {
                request = request.newBuilder()
                        .cacheControl(CacheControl.FORCE_CACHE)
                        .build();
                Log.d("net","no network");
            }
            Response originalResponse = chain.proceed(request);
            if (NetUtil.isNetworkAvailable()) {
                //有網的時候讀介面上的@Headers裡的配置，你可以在這裡進行統一的設定
                String cacheControl = request.cacheControl().toString();
                return originalResponse.newBuilder()
                        .header("Cache-Control", cacheControl)
                        .removeHeader("Pragma")
                        .build();
            } else {
                return originalResponse.newBuilder()
                        .header("Cache-Control", "public, only-if-cached, max-stale=" + CACHE_STALE_SEC)
                        .removeHeader("Pragma")
                        .build();
            }
        }
    };

    private final Interceptor mLoggingInterceptor = new Interceptor() {
        @Override
        public Response intercept(Chain chain) throws IOException {
            Request request = chain.request();
            Log.e("net",request.url()+"");
            long t1 = System.nanoTime();
            Log.i("net",String.format("Sending request %s on %s%n%s", request.url(), chain.connection(), request.headers()));
            Response response = chain.proceed(request);
            long t2 = System.nanoTime();
            Log.i("net",String.format(Locale.getDefault(), "Received response for %s in %.1fms%n%s",
                    response.request().url(), (t2 - t1) / 1e6d, response.headers()));
            return response;
        }
    };

    /**
     * @param hostType NETEASE_NEWS_VIDEO：1 （新聞，視訊），GANK_GIRL_PHOTO：2（圖片新聞）;
     *                 EWS_DETAIL_HTML_PHOTO:3新聞詳情html圖片)
     * 獲取不同的Service
     */
    public static NetService getDefault(int hostType)
    {
        NetManager netManager = sRetrofitManager.get(hostType);
        if (netManager == null)
        {
            netManager = new NetManager(hostType);
            sRetrofitManager.put(hostType, netManager);
        }
        return netManager.mNetService;
    }


    /**
     * 根據網路狀況獲取快取的策略
     */
    @NonNull
    private String getCacheControl() {
        return NetUtil.isNetworkAvailable() ? CACHE_CONTROL_AGE : CACHE_CONTROL_CACHE;
    }
}

定義一個介面的樣式

public interface NetService {

    /**
     * 載入圖片地址
     */
    @GET("data/福利/{pageCount}/{page}")
    Observable<PhotoEntity> getPhotoList(@Path("pageCount") int pageCount, @Path("page") int page);
}

最後進行網路訪問

 button.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Observable<PhotoEntity> observable= NetManager.getDefault(HostType.GANK_GIRL_PHOTO).getPhotoList(10, 1).compose(TransformUtils.<PhotoEntity>defaultSchedulers());
                observable.subscribe(new NetBaseSubscriber<PhotoEntity>(getApplicationContext()) {
                    @Override
                    public void onStart() {
                        super.onStart();
                    }

                    @Override
                    public void onCompleted() {
                        super.onCompleted();
                    }

                    @Override
                    public void onError(Throwable e) {
                        super.onError(e);
                    }

                    @Override
                    public void onNext(PhotoEntity photoEntity) {
                        super.onNext(photoEntity);
                        textView.setText(photoEntity.toString());
                    }
                });
            }
        });

下載地址