常见的HTTP客户端和代理

Question

我正在使用apache的常见httpclient库.是否可以通过代理发出HTTP请求？更具体地说,我需要使用代理列表来处理多线程POST请求(现在我正在使用单线程GET请求进行测试).

我试着用:

        httpclient.getHostConfiguration().setProxy("67.177.104.230", 58720);

我得到了该代码的错误:

21.03.2012. 20:49:17 org.apache.commons.httpclient.HttpMethodDirector executeWithRetry
INFO: I/O exception (java.net.ConnectException) caught when processing request: Connection refused: connect
21.03.2012. 20:49:17 org.apache.commons.httpclient.HttpMethodDirector executeWithRetry
INFO: Retrying request
21.03.2012. 20:49:19 org.apache.commons.httpclient.HttpMethodDirector executeWithRetry
INFO: I/O exception (java.net.ConnectException) caught when processing request: Connection refused: connect
21.03.2012. 20:49:19 org.apache.commons.httpclient.HttpMethodDirector executeWithRetry
INFO: Retrying request
21.03.2012. 20:49:21 org.apache.commons.httpclient.HttpMethodDirector executeWithRetry
INFO: I/O exception (java.net.ConnectException) caught when processing request: Connection refused: connect
21.03.2012. 20:49:21 org.apache.commons.httpclient.HttpMethodDirector executeWithRetry
INFO: Retrying request
org.apache.commons.httpclient.ProtocolException: The server xxxxx failed to respond with a valid HTTP response
    at org.apache.commons.httpclient.HttpMethodBase.readStatusLine(HttpMethodBase.java:1846)
    at org.apache.commons.httpclient.HttpMethodBase.readResponse(HttpMethodBase.java:1590)
    at org.apache.commons.httpclient.HttpMethodBase.execute(HttpMethodBase.java:995)
    at org.apache.commons.httpclient.ConnectMethod.execute(ConnectMethod.java:144)
    at org.apache.commons.httpclient.HttpMethodDirector.executeConnect(HttpMethodDirector.java:495)
    at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:390)
    at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:170)
    at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:396)
    at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:324)
    at test.main(test.java:42)

当我删除该行时,一切都按预期正常运行.

Answer 1

对于httpclient 4.1.x,您可以像这样设置代理(取自此示例):

    HttpHost proxy = new HttpHost("127.0.0.1", 8080, "http");

    DefaultHttpClient httpclient = new DefaultHttpClient();
    try {
        httpclient.getParams().setParameter(ConnRoutePNames.DEFAULT_PROXY, proxy);

        HttpHost target = new HttpHost("issues.apache.org", 443, "https");
        HttpGet req = new HttpGet("/");

        System.out.println("executing request to " + target + " via " + proxy);
        HttpResponse rsp = httpclient.execute(target, req);
        ...
    } finally {
        // When HttpClient instance is no longer needed,
        // shut down the connection manager to ensure
        // immediate deallocation of all system resources
        httpclient.getConnectionManager().shutdown();
    }

Answer 2

以下是如何使用HTTPClient(4.3.4)的最新版本执行此操作

    CloseableHttpClient httpclient = HttpClients.createDefault();
    try {
        HttpHost target = new HttpHost("localhost", 443, "https");
        HttpHost proxy = new HttpHost("127.0.0.1", 8080, "http");

        RequestConfig config = RequestConfig.custom()
                .setProxy(proxy)
                .build();
        HttpGet request = new HttpGet("/");
        request.setConfig(config);

        System.out.println("Executing request " + request.getRequestLine() + " to " + target + " via " + proxy);

        CloseableHttpResponse response = httpclient.execute(target, request);
        try {
            System.out.println("----------------------------------------");
            System.out.println(response.getStatusLine());
            EntityUtils.consume(response.getEntity());
        } finally {
            response.close();
        }
    } finally {
        httpclient.close();
    }

Answer 3

Apache的HTTPComponents版本4.3.x HttpClientBuilder类开始设定从系统属性中的代理默认http.proxyHost和http.proxyPort否则,你可以使用setProxy方法覆盖它们.

Answer 4

虽然这个问题很老,但我看到的还是没有确切的答案.我会在这里试着回答这个问题.

我相信这里的问题是如何设置Apache commons HttpClient(org.apache.commons.httpclient.HttpClient)的代理设置.

下面的代码段应该有效:

HttpClient client = new HttpClient();
HostConfiguration hostConfiguration = client.getHostConfiguration();
hostConfiguration.setProxy("localhost", 8080);
client.setHostConfiguration(hostConfiguration);