How to use an HTTP proxy in java

Question

I am writing a code that connects to websites and checks some code, like a crawler. But I need to connect trough a proxy and change the IP address (so it doesn't show the client's IP in the server logs).

How can this be done through java?

Answer 1

You can use the java system properties to set up a proxy or pass it as command line options.

You can find some details and samples here.

Ex: Before opening the connection

System.setProperty("http.proxyHost", "myProxyServer.com"); System.setProperty("http.proxyPort", "80"); 

Or you can use the default network proxies configured in the sytem

System.setProperty("java.net.useSystemProxies", "true"); 

Since Java 1.5 you can create a instance of proxy and pass it to the openConnection() method.

Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress("123.0.0.1", 8080)); URL url = new URL("http://www.yahoo.com"); HttpURLConnection uc = (HttpURLConnection)url.openConnection(proxy); uc.connect(); 

Or as lisak suggested, you can use some 3rd party libraries which supports your need better.