communicationserver.java

利用UDP实现网络聊天室

package communicationserver;

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

/**
 * <p>Title: 服务器端UDP通讯程序</p>
 * <p>Description: 用于服务器端，实现与客户端UDP通讯</p>
 * <p>Copyright: Copyright (c) 2002</p>
 * <p>Company: 北京师范大学计算机系</p>
 * @author 孙一林
 * @version 1.0
 */

public class CommunicationServer extends JFrame {
  JPanel contentPane;
  JLabel jLabel1 = new JLabel();
  JLabel jLabel2 = new JLabel();
  JTextField jTextField1 = new JTextField();
  JTextArea jTextArea1 = new JTextArea();
  private DatagramSocket sendSocket,receiveSocket;//声明发送数据报Socket和接收数据报Socket
  private DatagramPacket sendPacket,receivePacket;//声明发送数据报文包和接收数据报文包
  private String name,name1;

  /**Construct the frame*/
  public CommunicationServer() {
    enableEvents(AWTEvent.WINDOW_EVENT_MASK);
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }
  /**Component initialization*/
  private void jbInit() throws Exception  {
    jLabel1.setText("通讯记录：");
    jLabel1.setBounds(new Rectangle(4, 4, 67, 29));
    //setIconImage(Toolkit.getDefaultToolkit().createImage(CommunicationServer.class.getResource("[Your Icon]")));
    contentPane = (JPanel) this.getContentPane();
    contentPane.setLayout(null);
    this.setSize(new Dimension(400, 200));
    this.setTitle("通讯控制台:");
    jLabel2.setText("输入通讯内容：");
    jLabel2.setBounds(new Rectangle(11, 124, 93, 32));
    jTextField1.setText("通讯内容");
    jTextField1.setBounds(new Rectangle(118, 125, 269, 30));
    jTextField1.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
        jTextField1_actionPerformed(e);
      }
    });
    jTextArea1.setText("你好！");
    jTextArea1.setBounds(new Rectangle(7, 39, 380, 70));
    contentPane.add(jLabel1, null);
    contentPane.add(jTextArea1, null);
    contentPane.add(jTextField1, null);
    contentPane.add(jLabel2, null);
    try{
      sendSocket=new DatagramSocket();//实例化一个发送数据报Socket对象
      receiveSocket= new DatagramSocket(8000);//实例化一个接收数据报Socket对象
    }
    catch (SocketException e){
      e.printStackTrace();
      System.exit(1);
    }
  }

  /**方法waitForPacket用来监听来自于客户端的数据报，当获得数据报后，在文本显示区域显示出来*/
  public void waitForPacket(){
    while (true){
      try{
        byte buf[]=new byte[100];
        receivePacket=new DatagramPacket(buf,buf.length);//实例化一个接收数据报文包对象
        receiveSocket.receive(receivePacket);//以receivePacket为参数，接收数据包
        name=receivePacket.getAddress().toString();
        if(name1!=name){
          jTextArea1.append("\n来自主机："+name+"\n端口："+receivePacket.getPort());
        }
        jTextArea1.append("\n客户：\t");//将接收到的数据包中的数据显示出来
        byte[] data = receivePacket.getData();
        String receivedString = new String(data,0);
        jTextArea1.append(receivedString);
        name1=name;
      }
      catch(IOException e){
        jTextArea1.append("网络通讯出现错误，问题在"+e.toString());
      }
    }
  }
  /**Overridden so we can exit when window is closed*/
  protected void processWindowEvent(WindowEvent e) {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      System.exit(0);
    }
  }

  void jTextField1_actionPerformed(ActionEvent e) {
    try{
      jTextArea1.append("\n服务器：");
      String string = jTextField1.getText();
      jTextArea1.append(string);
      byte[] databyte=new byte[100];
      string.getBytes(0,string.length(),databyte,0);
      sendPacket=new DatagramPacket(databyte,string.length(),InetAddress.getByName(name),8001);
      sendSocket.send(sendPacket);
    }
    catch(IOException ioe){
      jTextArea1.append("网络通讯出现错误，问题在"+ioe.toString());
    }
  }
}