Retrofit2 - 如何仅缓存某些API调用

Question

我只想缓存某些不是全部的调用。这是代码我现在有，但它会影响所有改装电话：

int cacheSize = 10 * 1024 * 1024; // 10 MB 
Cache cache = new Cache(getCacheDir(), cacheSize); 

OkHttpClient okHttpClient = new OkHttpClient.Builder() 
    .cache(cache) 
    .build(); 

Retrofit.Builder builder = new Retrofit.Builder() 
    .baseUrl("http://10.0.2.2:3000/") 
    .client(okHttpClient) 
    .addConverterFactory(GsonConverterFactory.create()); 

Retrofit retrofit = builder.build(); 

有什么我可以把在标题也许当我想该呼叫只是做缓存？

例如：

//我想我就足以把一些在头中。我只想缓存客户端（android）端的调用。所以我认为改造可能会记住响应并将其缓存到下一个呼叫中，但我不希望它为我所有的呼叫，只是我想要的，可能是1或2，其余的可以一直连接到服务器。这是怎样实现的？

@Headers("Cache-Control:????XXXXX) //is it possible this way ?, how ? 
@GET("getBusiness.action")// Store information 
Call<RestaurantInfoModel> getRestaurantInfo(@Query("userId") String userId,@Query("businessId") String businessId); 

UPDATE：

这里是我现在已经尝试：

这是我如何打造出来的okhttpclient：

final OkHttpClient.Builder builder = new OkHttpClient.Builder(); 
int cacheSize = 10 * 1024 * 1024; // 10 MB 
Cache cache = new Cache(getCacheDir(), cacheSize); 
if (BuildConfig.RETROFIT_LOG_ALL) { 
    HttpLoggingInterceptor logging = new HttpLoggingInterceptor(); 
    logging.setLevel(HttpLoggingInterceptor.Level.BODY); 
    builder.addInterceptor(logging); 
} 
builder.cache(cache); 
return builder.build(); 

后来我把它添加到改造它的工作原理，但似乎没有缓存。让我们看看标题响应，但不添加缓存到okhttp：

Content-Type: application/json; charset=utf-8 
06-18 17:54:58.044 11233-11735/com.mobile.myapp.staging D/OkHttp: Connection: close 
06-18 17:54:58.044 11233-11735/com.mobile.myapp.staging D/OkHttp: Transfer-Encoding: chunked 
06-18 17:54:58.044 11233-11735/com.mobile.myapp.staging D/OkHttp: X-Powered-By: Express 
06-18 17:54:58.044 11233-11735/com.mobile.myapp.staging D/OkHttp: Vary: Origin 
06-18 17:54:58.044 11233-11735/com.mobile.myapp.staging D/OkHttp: Access-Control-Allow-Credentials: true 
06-18 17:54:58.044 11233-11735/com.mobile.myapp.staging D/OkHttp: Cache-Control: public, max-age=0 
06-18 17:54:58.044 11233-11735/com.mobile.myapp.staging D/OkHttp: ETag: W/"39ba-G9evSsiVDp9GAVGu1Mk4ag" 
06-18 17:54:58.044 11233-11735/com.mobile.myapp.staging D/OkHttp: Date: Sun, 18 Jun 2017 10:54:58 GMT 

所以这里是测试我看看是否缓存工作。我做了以此来为API的请求：

public interface CountriesApi { 
    @GET("countries") 
    @Headers({"Content-Type:application/json"}) 
    Observable<List<CountryModel>> getCountries(); 
} 

再后来，我关闭互联网的Android设备上，并试图再做德同一个呼叫，同时仍然在课程的应用程序。但是，我改变了抱怨，没有网络连接。相反，它应该刚刚从缓存中获得。任何想法什么是错的？

java.net.SocketException: Network is unreachable at 
java.net.PlainSocketImpl.socketConnect(Native Method) at 
java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:334) at 
java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:196) 
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:178) at 
java.net.SocksSocketImpl.connect(SocksSocketImpl.java:356) at 
java.net.Socket.connect(Socket.java:586) at 
okhttp3.internal.platform.AndroidPlatform.connectSocket(AndroidPlatform.java:63) 
at 
okhttp3.internal.connection.RealConnection.connectSocket(RealConnection.java:223) 
at okhttp3.internal.connection.RealConnection.connect(RealConnection.java:149) 
at 
okhttp3.internal.connection.StreamAllocation.findConnection(StreamAllocation.java:192) 
at 
okhttp3.internal.connection.StreamAllocation.findHealthyConnection(StreamAllocation.java:121) 
at 
okhttp3.internal.connection.StreamAllocation.newStream(StreamAllocation.java:100) 
at 
okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:42) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67) 
at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:93) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67) 
at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
at 
okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:120) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67) 
at 
okhttp3.logging.HttpLoggingInterceptor.intercept(HttpLoggingInterceptor.java:211) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67) 
at 
com.mobile.retrofit.NetworkSessionManager.intercept(NetworkSessionManager.java:38) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:92) 
at 
okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:67) 
at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:185) at 
okhttp3.RealCall.execute(RealCall.java:69) at 
retrofit2.OkHttpCall.execute(OkHttpCall.java:180) at 
retrofit2.adapter.rxjava2.CallExecuteObservable.subscribeActual(CallExecuteObservable.java:41) 
at io.reactivex.Observable.subscribe(Observable.java:10842) at 
retrofit2.adapter.rxjava2.BodyObservable.subscribeActual(BodyObservable.java:34) 
at io.reactivex.Observable.subscribe(Observable.java:10842) at 
io.reactivex.internal.operators.observable.ObservableFlatMap.subscribeActual(ObservableFlatMap.java:55) 
at io.reactivex.Observable.subscribe(Observable.java:10842) at 
io.reactivex.internal.operators.observable.ObservableSubscribeOn$SubscribeTask.run(ObservableSubscribeOn.java:96) 
at io.reactivex.Scheduler$DisposeTask.run(Scheduler.java:452) at 
io.reactivex.internal.schedulers.ScheduledRunnable.run(ScheduledRunnable.java:61) 
at 
io.reactivex.internal.schedulers.ScheduledRunnable.call(ScheduledRunnable.java:52) 
at java.util.concurrent.FutureTask.run(FutureTask.java:237) at 
java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:272) 
at 
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1133) 
at 
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:607) 
at java.lang.Thread.run(Thread.java:761) 

Answer 1

这是OkHttp库谁做了caching (doc)，它主要由响应头驱动。您应该检查它们并验证API响应是否被缓存。 OkHttp logging interceptor应该有助于调试。

要检查网络请求正在发生的事情用HttpLoggingInterceptor网络拦截，而不是应用程序拦截器（见https://github.com/square/okhttp/wiki/Interceptors）：当请求由高速缓存处理

HttpLoggingInterceptor interceptor = HttpLoggingInterceptor(); 
interceptor.setLevel(Level.BASIC); 
OkHttpClient client = new OkHttpClient.Builder() 
.addNetworkInterceptor(new LoggingInterceptor()) 
.build(); 

网络拦截器将不会被调用。

下一步将取决于情况。

1）所有API请求都被缓存。

然后，您应该可以使用注释@Headers（“Cache-Control：no-cache”）查找您想要缓存的不要的方法。

2）所有的API请求都没有被缓存。

然后，您可以更改API（添加适当的缓存标头），也可以为OkHttp实现网络拦截器，这将修改响应（标头）。你可以在这个回复中找到一些灵感：Can Retrofit with OKHttp use cache data when offline