import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.net.*;
import java.util.*;
import javax.swing.*;

/**
 * This program demonstrates how to use the URLConnection class for a POST request.
 * @version 1.20 2007-06-25
 * @author Cay Horstmann
 */
public class PostTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(new Runnable()
         {
            public void run()
            {
               JFrame frame = new PostTestFrame();
               frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
               frame.setVisible(true);
            }
         });
   }
}

class PostTestFrame extends JFrame
{
   /**
    * Makes a POST request and returns the server response.
    * @param urlString the URL to post to
    * @param nameValuePairs a map of name/value pairs to supply in the request.
    * @return the server reply (either from the input stream or the error stream)
    */
   public static String doPost(String urlString, Map<String, String> nameValuePairs)
         throws IOException
   {
      URL url = new URL(urlString);
      URLConnection connection = url.openConnection();
      connection.setDoOutput(true);

      PrintWriter out = new PrintWriter(connection.getOutputStream());

      boolean first = true;
      for (Map.Entry<String, String> pair : nameValuePairs.entrySet())
      {
         if (first) first = false;
         else out.print('&');
         String name = pair.getKey();
         String value = pair.getValue();
         out.print(name);
         out.print('=');
         out.print(URLEncoder.encode(value, "UTF-8"));
      }

      out.close();

      Scanner in;
      StringBuilder response = new StringBuilder();
      try
      {
         in = new Scanner(connection.getInputStream());
      }
      catch (IOException e)
      {
         if (!(connection instanceof HttpURLConnection)) throw e;
         InputStream err = ((HttpURLConnection) connection).getErrorStream();
         if (err == null) throw e;
         in = new Scanner(err);
      }

      while (in.hasNextLine())
      {
         response.append(in.nextLine());
         response.append("\n");
      }

      in.close();
      return response.toString();
   }

   public PostTestFrame()
   {
      setTitle("PostTest");

      northPanel = new JPanel();
      add(northPanel, BorderLayout.NORTH);
      northPanel.setLayout(new GridLayout(0, 2));
      northPanel.add(new JLabel("Host: ", SwingConstants.TRAILING));
      final JTextField hostField = new JTextField();
      northPanel.add(hostField);
      northPanel.add(new JLabel("Action: ", SwingConstants.TRAILING));
      final JTextField actionField = new JTextField();
      northPanel.add(actionField);
      for (int i = 1; i <= 8; i++)
         northPanel.add(new JTextField());

      final JTextArea result = new JTextArea(20, 40);
      add(new JScrollPane(result));

      JPanel southPanel = new JPanel();
      add(southPanel, BorderLayout.SOUTH);
      JButton addButton = new JButton("More");
      southPanel.add(addButton);
      addButton.addActionListener(new ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               northPanel.add(new JTextField());
               northPanel.add(new JTextField());
               pack();
            }
         });

      JButton getButton = new JButton("Get");
      southPanel.add(getButton);
      getButton.addActionListener(new ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               result.setText("");
               final Map<String, String> post = new HashMap<String, String>();
               for (int i = 4; i < northPanel.getComponentCount(); i += 2)
               {
                  String name = ((JTextField) northPanel.getComponent(i)).getText();
                  if (name.length() > 0)
                  {
                     String value = ((JTextField) northPanel.getComponent(i + 1)).getText();
                     post.put(name, value);
                  }
               }
               new SwingWorker<Void, Void>()
                  {
                     protected Void doInBackground() throws Exception
                     {
                        try
                        {
                           String urlString = hostField.getText() + "/" + actionField.getText();
                           result.setText(doPost(urlString, post));
                        }
                        catch (IOException e)
                        {
                           result.setText("" + e);
                        }
                        return null;
                     }
                  }.execute();
            }
         });

      pack();
   }

   private JPanel northPanel;
}