Java 改装-Okhttp客户端如何缓存响应

我试图缓存通过使用OkHttp（2.3.0）对（v1.9.0）进行改造而完成的http调用的响应。如果我尝试在没有internet的情况下拨打电话，它总是会拨打网络电话，然后

java.net.UnknownHostException

RestClient

OkHttpSingleTonClass

我的活动

---

我跟着。但我无法工作。它只是从服务器上点击。我做错了什么？

根据改型

1.9.0

使用的

OkClient

不支持缓存。我们必须使用Square

OkHttpClient

实例

OkHttpClient

库

您可以通过

compile'com.squareup.okhttp:okhttp:2.3.0'

在一切发生之前，通过响应头（如

Cache Control:max age=120，仅当已缓存时，max stale

**120是秒

您可以阅读更多关于标题的信息

缓存头主要由服务器响应指示。尝试在服务器中实现缓存头。如果你没有选择，是的，改装有

private static final Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = new Interceptor() {
    @Override
    public Response intercept(Chain chain) throws IOException {
        Response originalResponse = chain.proceed(chain.request());
        return originalResponse.newBuilder()
                .header("Cache-Control", String.format("max-age=%d, only-if-cached, max-stale=%d", 120, 0))
                .build();
    }
};

缓存位置：

将拦截器添加到OkHttpClient实例：

最后，将OkHttpClient添加到RestAdapter：

---

您可以浏览幻灯片以获取更多参考。

您可以测试和吗？我对Pragma头有一些问题，最后找到了一种方法，可以删除该头值。这里有一个演示项目，它将所有需要它的人的概念集合在一起。

public class OkHttpSingleTonClass {


private static OkHttpClient okHttpClient;

private OkHttpSingleTonClass() {
}

public static OkHttpClient getOkHttpClient() {
    if (okHttpClient == null) {
        okHttpClient = new OkHttpClient();
        createCacheForOkHTTP();
    }
    return okHttpClient;
}

private static void createCacheForOkHTTP() {
    Cache cache = null;
    cache = new Cache(getDirectory(), 1024 * 1024 * 10);
    okHttpClient.setCache(cache);
}

public static File getDirectory() {
    final File root = new File(Environment.getExternalStorageDirectory() + File.separator + "UCC" + File.separator);
    root.mkdirs();
    final String fname = UserUtil.CACHE_FILE_NAME;
    final File sdImageMainDirectory = new File(root, fname);
    return sdImageMainDirectory;
}

}

Request request = new Request.Builder()
            .cacheControl(new CacheControl.Builder()
                    .onlyIfCached()
                    .maxAge(60 * 60, TimeUnit.SECONDS)
                    .build())
            .url(RestClient.BASE_URL + Constants.GET_ABOUT_US_COLLECTION + "?userid=59e41b02-35ed-4962-8517-2668b5e8dae3&languageid=488d8f13-ef7d-4a3a-9516-0e0d24cbc720")
            .build();
    Log.d("url_request", RestClient.BASE_URL + Constants.GET_ABOUT_US_COLLECTION + "/?userid=10");
    com.squareup.okhttp.Response forceCacheResponse = null;
    try {
        forceCacheResponse = OkHttpSingleTonClass.getOkHttpClient().newCall(request).execute();
    } catch (IOException e) {
        e.printStackTrace();
    }
    if (forceCacheResponse.code() != 504) {
        // The resource was cached! Show it.
        Log.d("From", "Local");
        Toast.makeText(AboutUs.this, "Local", Toast.LENGTH_SHORT).show();
    } else {
        // The resource was not cached.
        Log.d("From", "Network");
        Toast.makeText(AboutUs.this, "Network", Toast.LENGTH_SHORT).show();
        getAbouUsDetails();//This will use the Apiservice interface to hit the server.

    } 

private static final Interceptor REWRITE_CACHE_CONTROL_INTERCEPTOR = new Interceptor() {
    @Override
    public Response intercept(Chain chain) throws IOException {
        Response originalResponse = chain.proceed(chain.request());
        return originalResponse.newBuilder()
                .header("Cache-Control", String.format("max-age=%d, only-if-cached, max-stale=%d", 120, 0))
                .build();
    }
};

private static void createCacheForOkHTTP() {
    Cache cache = null;
    cache = new Cache(getDirectory(), 1024 * 1024 * 10);
    okHttpClient.setCache(cache);
}

// returns the file to store cached details
private File getDirectory() {
    return new File(“location”);
}

okHttpClient.networkInterceptors().add(REWRITE_CACHE_CONTROL_INTERCEPTOR);

RestAdapter.setClient(new OkClient(okHttpClient));