[java] Common HTTPclient and proxy

I am using apache's common httpclient library. Is it possible to make HTTP request over proxy? More specific, I need to use proxy list for multithreaded POST requests (right now I am testing with single threaded GET requests).

I tried to use:

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

I get errors with that code:

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)

When I remove that line, everything runs fine as expected.

Although this question is very old, but I see still there are no exact answer. I will try to answer the question here.

I believe the question in short here is how to set the proxy settings for the Apache commons HttpClient (org.apache.commons.httpclient.HttpClient).

Code snippet below should work :

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

Here is how to do that with the last version of HTTPClient (4.3.4)

    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();
    }

I had a similar problem with HttpClient version 4.

I couldn't connect to the server because of a SOCKS proxy error and I fixed it using the below configuration:

client.getParams().setParameter("socksProxyHost",proxyHost);
client.getParams().setParameter("socksProxyPort",proxyPort);

Starting from Apache HTTPComponents 4.3.x HttpClientBuilder class sets the proxy defaults from System properties http.proxyHost and http.proxyPort or else you can override them using setProxy method.

If your software uses a ProxySelector (for example for using a PAC-script instead of a static host/port) and your HTTPComponents is version 4.3 or above then you can use your ProxySelector for your HttpClient like this:

ProxySelector myProxySelector = ...;
HttpClient myHttpClient = HttpClientBuilder.create().setRoutePlanner(new SystemDefaultRoutePlanner(myProxySelector))).build();

And then do your requests as usual:

HttpGet myRequest = new HttpGet("/");
myHttpClient.execute(myRequest);

Here is how I solved this problem for the old (< 4.3) HttpClient (which I cannot upgrade), using the answer of Santosh Singh (who I gave a +1):

HttpClient httpclient = new HttpClient();
if (System.getProperty("http.proxyHost") != null) {
  try {
    HostConfiguration hostConfiguration = httpclient.getHostConfiguration();
    hostConfiguration.setProxy(System.getProperty("http.proxyHost"), Integer.parseInt(System.getProperty("http.proxyPort")));
    httpclient.setHostConfiguration(hostConfiguration);
    this.getLogger().warn("USING PROXY: "+httpclient.getHostConfiguration().getProxyHost());
  } catch (Exception e) {
    throw new ProcessingException("Cannot set proxy!", e);
  }
}