Question:
How do I send e-mail from Java? Do I have to open a socket to a specific port on my server (and if so, which port and what should the data stream look like)? Or is there an easier way? Are there any restrictions on doing this from an applet?
Answer:
If the SMTP server is enabled on the machine thatruns your Web server, the following appletshould be able to generate e-mail.
The essence of the applet is the sendMsg() method,which opens a socket to port 25 of the appletsource (this is the standard SMTP port), feeds the expected SMTP header to this port, dumps the contents of a TextArea into the port (your message), then adds the required period and QUIT command.
*/import java.awt.*;import java.applet.*;import java.net.*;import java.io.*;public class Mailer extends Applet { private int SMTP_PORT = 25; private String appletSource = “zanzibar.ucsc.edu”; private TextArea MsgArea; private TextField senderField, recipientField, hostField; public void init() { setLayout(new BorderLayout()); Panel fields = new Panel(); fields.setLayout(new GridLayout(3, 1)); Panel recPanel = new Panel(); recPanel.setLayout(new GridLayout(2, 1)); recPanel.add(new Label(“Recipient”)); recipientField = new TextField(“”); recPanel.add(recipientField); fields.add(recPanel); Panel sendPanel = new Panel(); sendPanel.setLayout(new GridLayout(2, 1)); sendPanel.add(new Label(“Sender”)); senderField = new TextField(“president”); sendPanel.add(senderField); fields.add(sendPanel); Panel hostPanel = new Panel(); hostPanel.setLayout(new GridLayout(2, 1)); hostPanel.add(new Label(“Host”)); hostField = new TextField(“whitehouse.gov”); hostPanel.add(hostField); fields.add(hostPanel); add(“North”, fields); MsgArea = new TextArea(); add(“Center”, MsgArea); add(“South”, new Button(“SEND”)); } public boolean handleEvent(Event e) { if (e.id == Event.WINDOW_DESTROY) System.exit(0); return super.handleEvent(e); } public boolean action(Event e, Object arg) { if (arg.equals(“SEND”)) sendMsg(senderField.getText(), recipientField.getText(),hostField.getText()); else return super.action(e, arg); return true; } private void sendMsg(String sender, String recipient, String senderHost) { try { Socket s = new Socket(appletSource, SMTP_PORT); PrintStream out = new PrintStream(s.getOutputStream()); MsgArea.selectAll(); out.println(“HELO ” + senderHost); // SMTP doesn’t verify sender host! out.println(“MAIL FROM: ” + sender); out.println(“RCPT TO: ” + recipient); out.println(“DATA”); out.println(MsgArea.getSelectedText()); out.println(“.”); out.println(“QUIT”); } catch(Exception e) { System.out.println(“Error ” + e); } } // sendMsg} //Mailer 
