threadedmidlet.java

用J2ME实现简单电子邮件发送功能。 可以通过手机运行该程序

/* License
 * 
 * Copyright 1994-2004 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *  
 *  * Redistribution of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 * 
 *  * Redistribution in binary form must reproduce the above copyright notice,
 *      this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of contributors
 * may be used to endorse or promote products derived from this software
 * without specific prior written permission.
 *  
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING
 * ANY IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE
 * OR NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN MICROSYSTEMS, INC. ("SUN")
 * AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE
 * AS A RESULT OF USING, MODIFYING OR DISTRIBUTING THIS SOFTWARE OR ITS
 * DERIVATIVES. IN NO EVENT WILL SUN OR ITS LICENSORS BE LIABLE FOR ANY LOST
 * REVENUE, PROFIT OR DATA, OR FOR DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL,
 * INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER CAUSED AND REGARDLESS OF THE THEORY
 * OF LIABILITY, ARISING OUT OF THE USE OF OR INABILITY TO USE THIS SOFTWARE,
 * EVEN IF SUN HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.
 *  
 * You acknowledge that this software is not designed, licensed or intended
 * for use in the design, construction, operation or maintenance of any
 * nuclear facility. 
 */

import java.io.*;

import javax.microedition.io.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class ThreadedMIDlet
    extends MIDlet
    implements CommandListener {
  private Display mDisplay;
  private Form mMainForm;
  private Command mExitCommand, mConnectCommand;
  
  public void startApp() {
    mDisplay = Display.getDisplay(this);
    
    if (mMainForm == null) {
      mMainForm = new Form("PrimitiveMIDlet");
      mMainForm.append(new StringItem("",
      "Select Connect to make a network connection"));
      mExitCommand = new Command("Exit", Command.EXIT, 0);
      mConnectCommand = new Command("Connect", Command.SCREEN, 0);
      
      mMainForm.addCommand(mExitCommand);
      mMainForm.addCommand(mConnectCommand);
      mMainForm.setCommandListener(this);
    }
    
    mDisplay.setCurrent(mMainForm);
  }
  
  public void commandAction(Command c, Displayable s) {
    if (c == mExitCommand)
      notifyDestroyed();
    else if (c == mConnectCommand) {
      Thread t = new Thread() {
        public void run() {
          connect();
        }
      };
      t.start();
    }
  }

  private void connect() {
    String url = getAppProperty("NetworkThreading.URL");
    
    try {
      // Query the server and retrieve the response.
      HttpConnection hc = (HttpConnection)Connector.open(url);
      InputStream in = hc.openInputStream();
      
      // Pull back the server's response. If a content length is not
      // specified, we'll just read 255 bytes.
      int contentLength = (int)hc.getLength();
      if (contentLength == -1) contentLength = 255;
      byte[] raw = new byte[contentLength];
      int length = in.read(raw);
      
      // Clean up.
      in.close();
      hc.close();
      
      // Show the response to the user.
      String s = new String(raw, 0, length);
      Alert a = new Alert("Response", s, null, null);
      a.setTimeout(Alert.FOREVER);
      mDisplay.setCurrent(a, mMainForm);
    }
    catch (IOException ioe) {
      Alert a = new Alert("Exception", ioe.toString(), null, null);
      a.setTimeout(Alert.FOREVER);
      mDisplay.setCurrent(a, mMainForm);
    }
  }
  
  public void pauseApp() {}
  
  public void destroyApp(boolean unconditional) {}
}