有没有适当的解释如何添加缓存和ETAG / If-None-Match支持到Retrofit OkHttp？

我正在努力在2个项目中添加Etag支持,如果起初我怀疑HTTP头可能有问题,另一个项目的一切设置正确,并且缓存仍然无法正常工作.

以下是我尝试使其工作的尝试.结果显示,缓存似乎在应用程序的同一个实例中正常工作,但是一旦我重新启动,一切都会重新加载.

此外,在我的日志中,我没有看到If-None-Match被添加到请求中,所以我认为服务器不知道ETag,并且仍然完全重新计算响应.

以下是一些代码示例：

public class RetrofitHttpClient extends UrlConnectionClient

{

private OkUrlFactory generateDefaultOkUrlFactory()

{

OkHttpClient client = new com.squareup.okhttp.OkHttpClient();

try

{

Cache responseCache = new Cache(baseContext.getCacheDir(), SIZE_OF_CACHE);

client.setCache(responseCache);

}

catch (Exception e)

{

Logger.log(this, e, "Unable to set http cache");

}

client.setConnectTimeout(READ_TIMEOUT, TimeUnit.MILLISECONDS);

client.setReadTimeout(CONNECT_TIMEOUT, TimeUnit.MILLISECONDS);

return new OkUrlFactory(client);

}

private final OkUrlFactory factory;

public RetrofitHttpClient()

{

factory = generateDefaultOkUrlFactory();

}

@Override

protected HttpURLConnection openConnection(retrofit.client.Request request) throws IOException

{

return factory.open(new URL(request.getUrl()));

}

}

然后使用FULL日志级别和自定义标签创建Rest适配器：

restAdapter = new RestAdapter.Builder()

.setClient(new RetrofitHttpClient())

.setEndpoint(Config.BASE_URL)

.setRequestInterceptor(new SignatureSetter())

.setConverter(new JacksonConverter(JsonHelper.getObjectMapper()))

.setLogLevel(RestAdapter.LogLevel.FULL)

.setLog(new AndroidLog("=NETWORK="))

.build();

我在应用程序的第一个屏幕上有一个很长的请求进行测试.

当我打开应用程序 – 完成请求需要7秒钟.如果我暂停和恢复应用程序 – 相同的请求需要250ms,清楚地击中缓存.如果我完全关闭应用程序并重新启动 – 它再次需要7秒钟.

更新：

如所建议的,我使用了一个自定义的Retrofit构建并附加了一个LoggingInterceptor.这是我得到的

Received response for *** in 449,3ms

Date: Wed, 07 Jan 2015 09:02:23 GMT

Server: Apache

X-Powered-By: PHP/5.4.31

Access-Control-Allow-Credentials: true

Pragma:

Cache-Control: public, max-age=3600

X-Frame-Options: SAMEORIGIN

Etag: "hLxLRYztkinJAB453nRV7ncBSuU=-gzip"

Last-Modified: Wed, 24 Dec 2014 13:09:04 GMT

Vary: Accept-Encoding

Content-Encoding: gzip

Keep-Alive: timeout=2, max=100

Connection: Keep-Alive

Transfer-Encoding: chunked

Content-Type: application/json; charset=UTF-8

OkHttp-Selected-Protocol: http/1.1

OkHttp-Sent-Millis: 1420621288104

OkHttp-Received-Millis: 1420621288554

Sending request **** on Connection{****:80, proxy=DIRECT@ hostAddress=**** cipherSuite=none protocol=http/1.1}

Accept: application/json;

Host: ****

Connection: Keep-Alive

Accept-Encoding: gzip

User-Agent: okhttp/2.2.0

Response is equal to described above

如您所见,下一个请求中不存在If-None-Match标题