Java Language - Find proxy settings

Solution

Following example shows how to find proxy settings & create a proxy connection on a system using put method of systemSetting & getResponse method of HttpURLConnection class.

import java.net.HttpURLConnection;

import java.net.URL;

import java.util.Properties;

import java.net.InetSocketAddress;

import java.net.Proxy;

import java.net.ProxySelector;

import java.net.URI;

public class Main{

   public static void main(String s[]) throws Exception {

      try {

         Properties systemSettings = System.getProperties();

         systemSettings.put("proxySet", "true");

         systemSettings.put("http.proxyHost", "proxy.mycompany1.local");

         systemSettings.put("http.proxyPort", "80");

         URL u = new URL("http://www.google.com");

         HttpURLConnection con = (HttpURLConnection)u.openConnection();

         System.out.println(con.getResponseCode() + " : " + con.getResponseMessage());

         System.out.println(con.getResponseCode() == HttpURLConnection.HTTP_OK);

      } catch (Exception e) {

         e.printStackTrace();

         System.out.println(false);

      }

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

      Proxy proxy = (Proxy) ProxySelector.getDefault().select(new URI(

         "http://www.yahoo.com/")).iterator().

      next();;

      System.out.println("proxy hostname : " + proxy.type());

      InetSocketAddress addr = (InetSocketAddress)proxy.address();

      if (addr == null) {

         System.out.println("No Proxy");

      } else {

         System.out.println("proxy hostname : " + addr.getHostName());

         System.out.println("proxy port : " + addr.getPort());

      }

   }

}

Result

200 : OK

true

proxy hostname : HTTP

proxy hostname : proxy.mycompany1.local

proxy port : 80

example to find proxy settings of a System ?

import java.net.InetSocketAddress;

import java.net.Proxy;

import java.net.ProxySelector;

import java.net.URI;

import java.util.Iterator;

import java.util.List;

public class NewClass {

   public static void main(String[] args) {

      try {

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

         List<Proxy> l = ProxySelector.getDefault().select(

            new URI("http://www.google.com/"));

         for (Iterator<Proxy> iter = l.iterator(); iter.hasNext();) {

            Proxy proxy = iter.next();

            System.out.println("proxy hostname : " + proxy.type());

            InetSocketAddress addr = (InetSocketAddress) proxy.address();

            if (addr == null) {

               System.out.println("No Proxy");

            } else {

               System.out.println("proxy hostname : " + addr.getHostName());

               System.out.println("proxy port : " + addr.getPort());

            }

         }

      } catch (Exception e) {

         e.printStackTrace();

      }

   }

}