meetingmgframe.java

实现网络会议室功能

package meeting;

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

class Listener extends Thread{//用来监听端口消息的线程
	
	DatagramPacket packet;
	MulticastSocket socket;
	TextArea textArea;
	
    Listener(MulticastSocket socket1,TextArea textArea1){
		byte[] data = new byte[512];
		packet = new DatagramPacket(data,data.length);	
		socket = socket1;
		textArea = textArea1;	
	}
	
	public void run(){
	  String message;
	  	
      while(true){//不断的监测端口是否有新的消息
       	try
    	{
      		packet.setData(new byte[512]);                      //设定接收数据的DatagramPacket实例的数组大小
      		packet.setLength(512);                               //设定接收数据的DatagramPacket实例的长度
      		socket.receive(packet);                              //通过MulticastSocket实例端口从组播组接收数据
      		message = new String(packet.getData(), 0, packet.getLength());  //将接受的数据转换成字符串形式
      		textArea.append("\n" + message);
    	}
    	catch(Exception e1)
    	{
      		System.out.println("no new message,please wait" );                   //捕捉异常情况
    	}
      }
  	}

}


public class MeetingMGFrame extends JFrame{
  private JPanel contentPane;
  private TextField textField1 = new TextField();//输入要发送的消息
  private TextField textField2 = new TextField();//输入组播组地址
  private TextField textField3 = new TextField();//输入用户名
  private Button button1 = new Button();//发送消息按钮
  private Button button2 = new Button();//进入组播组按钮
  private Label label1 = new Label();//提示输入消息
  private Label label2 = new Label();//显示组播组信息
  private Label label3 = new Label();//提示输入用户名
  private TextArea textArea1 = new TextArea();//显示组播组传来的消息
  int port;                                       //声明组播使用的端口
  MulticastSocket socket;                          //声明建立组播组使用的MulticastSocket类
  InetAddress group;                               //声明建立组播组使用的组播组地址
  DatagramPacket packet;                           //声明发送和接收数据所使用的DatagramPacket类
  String user = new String();						//声明用户名
  boolean connected = false;						//是否连接的标志符

  public MeetingMGFrame() {
    enableEvents(AWTEvent.WINDOW_EVENT_MASK);
    try {
      toInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }
  
  private void toInit() throws Exception  {//初始化窗体
    contentPane = (JPanel) this.getContentPane();            //设计窗体布局
    contentPane.setLayout(null);
    this.setSize(new Dimension(400, 400));
    this.setTitle("组播实现网络会议");
    textField1.setBounds(new Rectangle(90,260,200,20));
    textField2.setBounds(new Rectangle(90,20,65,20));
    textField3.setBounds(new Rectangle(210,20,80,20));
    textField2.setText("224.0.0.1");
    label1.setBounds(new Rectangle(20, 260, 60, 20));
    label2.setBounds(new Rectangle(10, 20, 60, 20));
    label3.setBounds(new Rectangle(160,20,40,20));
    label1.setText("输入消息：");
    label2.setText("输入组播组ip:");
    label3.setText("用户名");
    textArea1.setBounds(new Rectangle(20,60,320,180));
    textArea1.setEditable(false);
    button1.setLabel("发送消息");
    button1.setBounds(new Rectangle(300, 260, 60, 20));
    button1.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        button1_actionPerformed(e);
      }
    });
    button2.setLabel("进入会议");
    button2.setBounds(new Rectangle(300, 20, 60, 20));
    button2.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        button2_actionPerformed(e);
      }
    });
    contentPane.add(textField1, null);
    contentPane.add(textField2,null);
    contentPane.add(textField3,null);
    contentPane.add(button1, null);
    contentPane.add(button2,null);
    contentPane.add(label1, null);
    contentPane.add(label2,null);
    contentPane.add(label3,null);
    contentPane.add(textArea1,null);
  }
  
  protected void processWindowEvent(WindowEvent e) {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      System.exit(0);
    }
  }
  
  public void createMulticastGroupAndJoin()           //创建一个组播组并加入该组
  {
  	String str1 = new String();
  	String str2 = new String();
  	str1 = textField2.getText();
  	str2 = textField3.getText();
  	
  	if(str1.compareTo("") != 0 && str2.compareTo("") != 0 ){
    	try
    	{
    		user = str2;									   //获取用户名
      		port = 1234;                                      //设置组播组的监听端口
      		group = InetAddress.getByName(textField2.getText());       //设置组播组的地址为224.0.0.1
      		socket = new MulticastSocket(port);               //初始化MulticastSocket类并将端口号与之关联
      		socket.joinGroup(group);                           //加入此组播组
      		label2.setText("进入组播组：");						//提示已经进入组播组
      		connected = true;
      		
    	}
    	catch(Exception e1)
    	{
      		System.out.println("Error1: " + e1);               //捕捉异常情况
	   	}

		byte[] data = new byte[512];
		packet = new DatagramPacket(data, data.length, group, port);    //初始化DatagramPacket的实例
  
  		try
  		{
	
			String str = new String();
    		str = user +"进入组播组：" + textField2.getText();		//字符串形式的用户进入组的消息
    		data = str.getBytes();       						//将所要发送的数据转换为字节形式并存储在数组中
    		packet.setData(data);				  				//将字节形式的消息放入packet
    		socket.send(packet);                                       //通过MulticastSocket实例端口向组播组发送数据
  		}
  
 	 	catch(Exception e)
  		{
  			System.out.println("Error2:" + e);
  		}
	
		Listener listener = new Listener(socket,textArea1);  	//初始化侦听端口用的线程
		listener.start();									    //激活线程
	  }//end of if
  
 	 else{
		  textArea1.setText("请确认输入组播组的ip地址和您的用户名");
 	  }	
  }

  public void sendData()                                //向组播组发送数据的函数
  {
    try
    {
      String str = new String();
      str = user +":" + textField1.getText();
      byte[] data = str.getBytes();       				//将用户所要发送的数据转换为字节形式并存储在数组中
      packet.setData(data);				  				//将字节形式的消息放入packet
      socket.send(packet);                                   //通过MulticastSocket实例端口向组播组发送数据
    }
    catch(Exception e1)
    {
      System.out.println("Error3: " + e1);                   //捕捉异常情况
    }
  }


  void button1_actionPerformed(ActionEvent e) {
  	sendData();                                             //向组播组发送数据
  }
  
  void button2_actionPerformed(ActionEvent e){
  	if(!connected){
  		createMulticastGroupAndJoin();
  	}
  	else{
  		textArea1.append("\n已经建立连接，请发送消息");	
  	}
  }
}