关闭 CloseableHttpResponse/CloseableHttpClient 的正确方法 [重复]

Question

我正在使用 CloseableHttpResponse（来自 apache-httpclient-4.5.3），但我不确定我是否正确使用它，我看到 answer with no votes 最终使用 EntityUtils.consume：

CloseableHttpResponse response1 = httpclient.execute(httpGet);

try {

 System.out.println(response1.getStatusLine());

} finally {

 EntityUtils.consume(response1.getEntity());

CloseableHttpClient 是抽象的，没有可调用的关闭方法，尽管在此 answer 中使用了它：

CloseableHttpResponse response = httpclient.execute(httpget);
try {
    //do something
} finally {
    response.close();
}

目前我在发送方法中使用 CloseableHttpClient 和 CloseableHttpResponse 的资源。

我没有错过任何打开的资源或以错误的方式使用它吗？

private CloseableHttpResponse send()
            throws URISyntaxException, UnsupportedEncodingException, IOException, ClientProtocolException {
        URIBuilder uriBuilder = new URIBuilder(BASE_URL);
        HttpHost target = new HttpHost(uriBuilder.getHost(), uriBuilder.getPort(), uriBuilder.getScheme());
        HttpPost post = new HttpPost(uriBuilder.build());
        try (CloseableHttpClient httpClient = HttpClients.custom().build(); CloseableHttpResponse response = httpClient.execute(target, post)) {            
            return response;
        }
    

Answer 1

在文档here中有详细解释。
在这里引用文档中的伪代码是分配/取消分配CloseableHttpClient 实例的典型方法：

try (CloseableHttpClient httpclient = HttpClients.createDefault()) {
    <...>
}

同样适用于CloseableHttpResponse:

try (CloseableHttpResponse response = httpclient.execute(httpget)) {
    <...>
}

现在，关于CloseableHttpClient 中的关闭方法。 CloseableHttpClient 是实现Closeable 接口的抽象类。也就是说，虽然它本身没有close 方法，但扩展它的类需要实现close 方法。一类是InternalHttpClient。详情可以查看源代码。

在 Java7 之前，需要显式关闭：

CloseableHttpClient httpclient = HttpClients.createDefault();
try {
    <...>
} finally {
    httpclient.close();
}

CloseableHttpResponse response = httpclient.execute(httpget);
try {
    <...>
} finally {
    response.close();
}

Answer 2

你可以通过使用 try(resource) 来避免 finally

try (CloseableHttpResponse 响应 = httpclient.execute(httpGet)) { ... }