java - 常用的HTTP客户端和代理

Question

我正在使用 apache 的通用 httpclient 库。是否可以通过代理发出 HTTP 请求？更具体地说，我需要对多线程 POST 请求使用代理列表(现在我正在使用单线程 GET 请求进行测试)。

我尝试使用:

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

我收到该代码的错误:

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，一切都按预期运行。

Answer 1

对于 httpclient 4.1.x，您可以像这样设置代理(取自 this example):

    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();
    }