chatapplet.java

网络聊天室

import java.awt.*;
import java.awt.event.*;
import java.applet.*;
import java.net.*;
import java.io.*;
import java.util.*;

public class chatApplet extends Applet {

  Panel panel1 = new Panel();        //用于放置输入姓名和连接两个按钮
  BorderLayout borderLayout1 = new BorderLayout();
  Panel panel2 = new Panel();        
  Panel panel3 = new Panel();        //用于放置发送信息区域
  FlowLayout flowLayout1 = new FlowLayout();
  FlowLayout flowLayout2 = new FlowLayout();
  Label label1 = new Label();
 // Label label11 = new Label();
  TextField name_txt = new TextField(15);
  Button button1 = new Button();
  Button button2 = new Button();
  TextArea chat_txt = new TextArea(15,30);
  Label label2 = new Label();
  Button button3 = new Button();
  TextField msg_txt = new TextField(20);
  java.awt.List list1 = new java.awt.List(13);
  
  Socket soc=null;                   //定义连接套接字
  PrintStream ps=null;                
  Listen listen=null;               
  public void init()                 //初始化图形界面
	{
	  resize(475,350);  
     this.setLayout(borderLayout1);
    panel2.setLayout(flowLayout1);
    panel3.setLayout(flowLayout2);
    label1.setText("姓名：");
    //label11.setText("socket简易聊天室"); 
    button1.setLabel("连接");
    button2.setLabel("断开连接");
    chat_txt.setEditable(false);
    panel2.setBackground(Color.cyan);
    panel1.setBackground(Color.cyan);
    label2.setText("聊天信息：");
    button3.setLabel("发送");
    msg_txt.setText("please input a message");
    panel3.setBackground(Color.cyan);
    this.add(panel1, BorderLayout.NORTH);
    panel1.add(label1, null);
    panel1.add(name_txt, null);
    panel1.add(button1, null);
    panel1.add(button2, null);
    this.add(panel2, BorderLayout.CENTER);
    panel2.add(chat_txt, null);
    panel2.add(list1, null);
    this.add(panel3,  BorderLayout.SOUTH);
    panel3.add(label2, null);
    panel3.add(msg_txt, null);
    panel3.add(button3, null);
    
  }

  public boolean action(Event evt,Object obj)    //事件触发代码
	{
      if(evt.target instanceof Button)
		{
	     String label=(String) obj;
		 if(label.equals("连接"))               
			{
		     if(soc==null)
			 	{
			     try
					{
					 soc=new Socket(InetAddress.getLocalHost(),2525);     //使用端口2525实例化一个本地套接字
					 System.out.println(soc);                             
					 ps=new PrintStream(soc.getOutputStream());          
					 StringBuffer info=new StringBuffer("INFO: ");        
					                                                      //其中INFO为关键字让服务器识别为连接信息
																		  
					 String userinfo=name_txt.getText()+":"+InetAddress.getLocalHost().toString();
					 ps.println(info.append(userinfo));
				
					 ps.flush();
					 listen=new Listen(this,name_txt.getText(),soc);   
					 listen.start();                                    //启动线程
				 }
				 catch(IOException e)
					{
				     System.out.println("错误:"+e);
					 disconnect();
				 }
			 }   //end of if
		 }//end of if
	   else if(label.equals("断开连接"))                               //如果点击断开连接按钮则运行disconnect()
			{
	         disconnect();
	   }
	   else if(label.equals("发送"))                                 //如果点击发送按钮
			{
	         if(soc!=null)
				{
			     StringBuffer msg=new StringBuffer("MSG: ");        //定义并实例化一个字符缓冲存储发送的聊天信息
				                                                    
				 try
				 {
				        String msgtxt=new String(msg_txt.getText());
				 }
				 catch(Exception e){}
				 
				 ps.println(msg.append(msg_txt.getText()));          
				 ps.flush();
			 }
	   }
	  }
     return true;
  }   //end of method action

  public void disconnect()                                         
	{
     if(soc!=null)
		{
	     try
			{
		    listen.suspend();
			ps.println("QUIT");                                 
			ps.flush();
			soc.close();                                            //关闭套接字
		 }
		 catch(IOException e)
			{
		     System.out.println("Error:"+e);
		 }
		 finally
			{
			 
		 }
	 }// end of if
  }

  class Listen extends Thread       //客户端线程类用来监听服务器传来的信息
{
 String name=null;                  
 DataInputStream dis=null;          
 PrintStream ps=null;               
 Socket socket=null;                
 chatApplet parent=null;             //用来存储当前运行的chatApplet实例

 public Listen(chatApplet p,String n,Socket s)   
	{
   
	 parent=p;
	 name=n;
	 socket=s;

	 try
		{
	
	     dis=new DataInputStream(s.getInputStream());
		 ps=new PrintStream(s.getOutputStream());

	 }
	 catch(IOException e)
		{
	     System.out.println("Error:"+e);
		 parent.disconnect();
	   }
    }   //end of Listen constractor
  
 public void run()                               //线程运行方法
	{
      String msg=null;
	  while(true)
		{
	     try{msg=dis.readLine();}
	   //  msg=dis.readUTF();}                 //读取从服务器传来的信息
		 catch(IOException e)
			{
		     System.out.println("Error:"+e);
			 parent.disconnect();
		 }
		 if (msg==null)                           //如果从服务器传来的信息为空则断开此次连接
		 {
		   parent.listen=null;              
		   parent.soc=null;
		   parent.list1.clear();
		   return;
		 }
		 StringTokenizer st=new StringTokenizer(msg,":");   
		 String keyword=st.nextToken();                    

		 if(keyword.equals("PEOPLE"))                     
		                                                  
			{
		     parent.list1.clear();
			 while(st.hasMoreTokens())                     //遍历st取得目前所连接的客户
				{
			     String str=st.nextToken();
				 parent.list1.addItem(str);
			 }
		 }
		 else if(keyword.equals("MSG"))                   
		                                                  
			{
		     String usr=st.nextToken();
			 parent.chat_txt.appendText(usr);
			 parent.chat_txt.appendText(st.nextToken("\0"));
			 parent.chat_txt.appendText("\n\n");
		 }
		 else if(keyword.equals("QUIT"))                
		                                                //用来切断此次连接
			{
		     System.out.println("Quit");
		     try
		     {parent.listen.stop();
		      parent.listen=null;
		      parent.soc.close();
			  parent.soc=null;
             }catch(IOException e)
             {
             	System.out.println("Error:"+e);
             	}
			  parent.list1.clear();
			 
			 return;
		 }
	  }

 }     //end of run method
}      //end of Listen inner class


 
}     //end of chatApplet class