How to connect a Socket server via HTTP proxy

Question

I have a piece of code to connect to a Socket server, and it works fine.

Socket socket = new Socket();
socket.connect(new InetSocketAddress(address, port));
         


        

Answer 1

Well, you can manage the proxy by setting the requested url right after the proxy's url, or using Java URL as following:

URL u = new URL("http", ProxyHost, ProxyPort, destinationAddress);

By using this you build an URL like http://ProxyHost:ProxyPorthttp://destinationAddress so you don't have to set a Proxy class instance in Java that will likely throw the mentioned exception:

java.lang.IllegalArgumentException: Proxy is null or invalid type
    at java.net.Socket.(Socket.java:88)

If you need to manage authentication settings you can always set the authenticator as default.

final String authUser = myAuthUser;
        final String authPassword = myAuthPassword;
        Authenticator.setDefault(
           new Authenticator() {
              public PasswordAuthentication getPasswordAuthentication() {
                 return new PasswordAuthentication(
                       authUser, authPassword.toCharArray());
              }
           }
        );

Even though it's a very "rudimental" way to set a proxy it's very likely to work for HTTP Type Proxies if that's the kind of proxy you have to set.