CloseableHttpResponse.close（）和httpPost.releaseConnection（）之间有什么区别？ [英] what's the difference between CloseableHttpResponse.close() and httpPost.releaseConnection()?

问题描述

CloseableHttpResponse response = null;
try {
    // do some thing ....
    HttpPost request = new HttpPost("some url");
    response = getHttpClient().execute(request);
    // do some other thing ....
} catch(Exception e) {
    // deal with exception
} finally {
    if(response != null) {
        try {
            response.close(); // (1)
        } catch(Exception e) {}
        request.releaseConnection(); // (2)
    }
}

我做了一个http请求如上所述。

I've made a http request like above.

为了释放底层连接，调用（1）和（2）是否正确？两次调用有什么区别？

In order to release the underlying connection, is it correct to call (1) and (2)? and what's the difference between the two invocation?

推荐答案

简答：

request.releaseConnection（）正在释放底层HTTP连接以允许它被重用。 response.close（）正在关闭一个流（不是连接），这个流是我们从网络套接字流传输的响应内容。

request.releaseConnection() is releasing the underlying HTTP connection to allow it to be reused. response.close() is closing a stream (not a connection), this stream is the response content we are streaming from the network socket.

长答案：

在任何最新版本> 4.2中可能遵循的正确模式，甚至可能在此之前，不使用 releaseConnection 。

The correct pattern to follow in any recent version > 4.2 and probably even before that, is not to use releaseConnection.

request.releaseConnection（）发布基础httpConnection，以便可以重用请求，但Java文档说：

request.releaseConnection() releases the underlying httpConnection so the request can be reused, however the Java doc says:

简化从HttpClient 3.1 API迁移的便捷方法......

A convenience method to simplify migration from HttpClient 3.1 API...

我们确保响应内容被完全消耗，而不是释放连接，这反过来确保连接被释放并准备好重用。一个简短的例子如下所示：

Instead of releasing the connection, we ensure the response content is fully consumed which in turn ensures the connection is released and ready for reuse. A short example is shown below:

CloseableHttpClient httpclient = HttpClients.createDefault();
HttpGet httpGet = new HttpGet("http://targethost/homepage");
CloseableHttpResponse response1 = httpclient.execute(httpGet);
try {
    System.out.println(response1.getStatusLine());
    HttpEntity entity1 = response1.getEntity();
    // do something useful with the response body
    String bodyAsString = EntityUtils.toString(exportResponse.getEntity());
    System.out.println(bodyAsString);
    // and ensure it is fully consumed (this is how stream is released.
    EntityUtils.consume(entity1);
} finally {
    response1.close();
}

这篇关于CloseableHttpResponse.close（）和httpPost.releaseConnection（）之间有什么区别？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！