smtpclient.java

《JAVA分布式程序设计》一书的源代码。

import java.io.*;
import java.net.*;
/**
 * @(#)smtpClient.java
 * @author Qusay H. Mahmoud
 */
public class smtpClient {
   public static void main(String[] args) {
      Socket smtpSocket = null;
      DataOutputStream os = null;
      BufferedReader is = null;
      try {
        smtpSocket = new Socket("MailMachine.com", 25);
        os = new DataOutputStream(smtpSocket.getOutputStream());
        is = new BufferedReader(new InputStreamReader (smtpSocket.getInputStream()));
      } catch (UnknownHostException e) {
        System.err.println("Don't know host: hostname");
      } catch (IOException e) {
         System.err.println("Couldn't get I/O to");
      }
      // If everything has been initialized then we want to write some data to
      // the socket we have opened a connection to on port 25
      if (smtpSocket != null && os != null &&is != null) {
         try {
           // The capital string before each colon has a   
           // special meaning to SMTP you may want to read 
           // the SMTP specification, RFC1822/1823
           os.writeBytes("HELO\n");
           os.writeBytes("MAIL From: [e-mail]");
           os.writeBytes("RCPT To:[e-mail]\n");
           os.writeBytes("DATA\n");
      	   os.writeBytes("From: [e-mail]\n");
      	   os.writeBytes("Subject: testing\n");
      	   os.writeBytes("Hi there\n"); // message body
      	   os.writeBytes("\n.\n");
      	   os.writeBytes("QUIT");
           // keep on reading from/to the socket till we receive the "Ok" from 
           // SMTP, once we received that then we want to break.
      	   String responseLine;
      	   while ((responseLine = is.readLine()) != null) {
             System.out.println("Server: " +responseLine);
             if (responseLine.indexOf("Ok") != -1) {
               break;
             }
      	   }
           // clean up:
           os.close();
           is.close();
           smtpSocket.close();
    	 } catch (UnknownHostException e) {
            System.err.println("Trying to connect to unknown host: " +e);
         } catch (IOException e) {
  	    System.err.println("IOException:  " + e);
         }
      }
   }
}