This program shows how to use sockets to send plain text mail messages. : Socket « Network Protocol « Java

1. Java
2. Network Protocol
3. Socket

This program shows how to use sockets to send plain text mail messages.

 
/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.PrintWriter;
import java.net.InetAddress;
import java.net.Socket;
import java.util.Scanner;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.SwingWorker;

/**
 * This program shows how to use sockets to send plain text mail messages.
 * @author Cay Horstmann
 * @version 1.11 2007-06-25
 */
public class MailTest
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(new Runnable()
         {
            public void run()
            {
               JFrame frame = new MailTestFrame();
               frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
               frame.setVisible(true);
            }
         });
   }
}

/**
 * The frame for the mail GUI.
 */
class MailTestFrame extends JFrame
{
   public MailTestFrame()
   {
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
      setTitle("MailTest");

      setLayout(new GridBagLayout());

      // we use the GBC convenience class of Core Java Volume 1 Chapter 9
      add(new JLabel("From:"), new GBC(0, 0).setFill(GBC.HORIZONTAL));

      from = new JTextField(20);
      add(from, new GBC(1, 0).setFill(GBC.HORIZONTAL).setWeight(100, 0));

      add(new JLabel("To:"), new GBC(0, 1).setFill(GBC.HORIZONTAL));

      to = new JTextField(20);
      add(to, new GBC(1, 1).setFill(GBC.HORIZONTAL).setWeight(100, 0));

      add(new JLabel("SMTP server:"), new GBC(0, 2).setFill(GBC.HORIZONTAL));

      smtpServer = new JTextField(20);
      add(smtpServer, new GBC(1, 2).setFill(GBC.HORIZONTAL).setWeight(100, 0));

      message = new JTextArea();
      add(new JScrollPane(message), new GBC(0, 3, 2, 1).setFill(GBC.BOTH).setWeight(100, 100));

      comm = new JTextArea();
      add(new JScrollPane(comm), new GBC(0, 4, 2, 1).setFill(GBC.BOTH).setWeight(100, 100));

      JPanel buttonPanel = new JPanel();
      add(buttonPanel, new GBC(0, 5, 2, 1));

      JButton sendButton = new JButton("Send");
      buttonPanel.add(sendButton);
      sendButton.addActionListener(new ActionListener()
         {
            public void actionPerformed(ActionEvent event)
            {
               new SwingWorker<Void, Void>()
               {
                  protected Void doInBackground() throws Exception
                  {
                     comm.setText("");
                     sendMail();
                     return null;
                  }
               }.execute();
            }
         });
   }

   /**
    * Sends the mail message that has been authored in the GUI.
    */
   public void sendMail()
   {
      try
      {
         Socket s = new Socket(smtpServer.getText(), 25);

         InputStream inStream = s.getInputStream();
         OutputStream outStream = s.getOutputStream();

         in = new Scanner(inStream);
         out = new PrintWriter(outStream, true /* autoFlush */);

         String hostName = InetAddress.getLocalHost().getHostName();

         receive();
         send("HELO " + hostName);
         receive();
         send("MAIL FROM: <" + from.getText() + ">");
         receive();
         send("RCPT TO: <" + to.getText() + ">");
         receive();
         send("DATA");
         receive();
         send(message.getText());
         send(".");
         receive();
         s.close();
      }
      catch (IOException e)
      {
         comm.append("Error: " + e);
      }
   }

   /**
    * Sends a string to the socket and echoes it in the comm text area.
    * @param s the string to send.
    */
   public void send(String s) throws IOException
   {
      comm.append(s);
      comm.append("\n");
      out.print(s.replaceAll("\n", "\r\n"));
      out.print("\r\n");
      out.flush();
   }

   /**
    * Receives a string from the socket and displays it in the comm text area.
    */
   public void receive() throws IOException
   {
      String line = in.nextLine();
      comm.append(line);
      comm.append("\n");
   }

   private Scanner in;
   private PrintWriter out;
   private JTextField from;
   private JTextField to;
   private JTextField smtpServer;
   private JTextArea message;
   private JTextArea comm;

   public static final int DEFAULT_WIDTH = 300;
   public static final int DEFAULT_HEIGHT = 300;
}

/*
This program is a part of the companion code for Core Java 8th ed.
(http://horstmann.com/corejava)

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/*
GBC - A convenience class to tame the GridBagLayout

Copyright (C) 2002 Cay S. Horstmann (http://horstmann.com)

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
*/


/**
This class simplifies the use of the GridBagConstraints
class.
*/
class GBC extends GridBagConstraints 
{
/**
   Constructs a GBC with a given gridx and gridy position and
   all other grid bag constraint values set to the default.
   @param gridx the gridx position
   @param gridy the gridy position
*/
public GBC(int gridx, int gridy)
{
   this.gridx = gridx;
   this.gridy = gridy;
}

/**
   Constructs a GBC with given gridx, gridy, gridwidth, gridheight
   and all other grid bag constraint values set to the default.
   @param gridx the gridx position
   @param gridy the gridy position
   @param gridwidth the cell span in x-direction
   @param gridheight the cell span in y-direction
*/
public GBC(int gridx, int gridy, int gridwidth, int gridheight)
{
   this.gridx = gridx;
   this.gridy = gridy;
   this.gridwidth = gridwidth; 
   this.gridheight = gridheight; 
}

/**
   Sets the anchor.
   @param anchor the anchor value
   @return this object for further modification
*/
public GBC setAnchor(int anchor) 
{ 
   this.anchor = anchor; 
   return this;
}

/**
   Sets the fill direction.
   @param fill the fill direction
   @return this object for further modification
*/
public GBC setFill(int fill) 
{ 
   this.fill = fill; 
   return this;
}

/**
   Sets the cell weights.
   @param weightx the cell weight in x-direction
   @param weighty the cell weight in y-direction
   @return this object for further modification
*/
public GBC setWeight(double weightx, double weighty) 
{ 
   this.weightx = weightx; 
   this.weighty = weighty; 
   return this;
}

/**
   Sets the insets of this cell.
   @param distance the spacing to use in all directions
   @return this object for further modification
*/
public GBC setInsets(int distance) 
{ 
   this.insets = new Insets(distance, distance, distance, distance);
   return this;
}

/**
   Sets the insets of this cell.
   @param top the spacing to use on top
   @param left the spacing to use to the left
   @param bottom the spacing to use on the bottom
   @param right the spacing to use to the right
   @return this object for further modification
*/
public GBC setInsets(int top, int left, int bottom, int right) 
{ 
   this.insets = new Insets(top, left, bottom, right);
   return this;
}

/**
   Sets the internal padding
   @param ipadx the internal padding in x-direction
   @param ipady the internal padding in y-direction
   @return this object for further modification
*/
public GBC setIpad(int ipadx, int ipady) 
{ 
   this.ipadx = ipadx; 
   this.ipady = ipady; 
   return this;
}
}

   
  

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