java实现简易局域网聊天功能

/* 使用UDP模式,编写一个聊天程序 有发送和接收数据2部分, 一个线程接收,一个线程发送  由于发送和接收动作是不一致的,所以要使用2个run方法 而且这两个方法要封装到不同的类中  本程序忽略了部分异常的处理,也未加入UI组件 这样比较简洁  发送端口9998 接受端口9999 用的是局域网广播地址,所以自己发的消息自己也收到了  [示例]:简易控制台聊天程序 */ import java.net.*; import java.io.*; class Demo {  public static void main(String[] args) throws Exception  {   DatagramSocket sendSocket = new DatagramSocket(9998); //发送端   DatagramSocket receSocket = new DatagramSocket(9999); //接收端   new Thread(new MsgSend(sendSocket)).start();      //发送线程   new Thread(new MsgRece(receSocket)).start();      //接受线程  } }  class MsgSend implements Runnable   //发送 {  private DatagramSocket dsock;  public MsgSend(DatagramSocket dsock)  {   this.dsock= dsock;  }   public void run()  {   BufferedReader bufr = new BufferedReader(new InputStreamReader(System.in));   String lineStr = null;   try   {        while(true)    {     lineStr = bufr.readLine();     if(lineStr!=null)     {      if(lineStr.equals("over886"))      {       break;      }      else      {       byte[] dataBuf = lineStr.getBytes();       DatagramPacket dataPack =  //数据打包       new DatagramPacket( dataBuf,                 dataBuf.length,                 InetAddress.getByName("192.168.1.255"), //广播                 9999 //目标端口                );       dsock.send(dataPack);      }     }    }    bufr.close();    dsock.close();   }   catch(Exception e)   {    throw new RuntimeException("发送失败!");   }  } }  class MsgRece implements Runnable  //接收 {  private DatagramSocket dsock;  public MsgRece(DatagramSocket dsock)  {   this.dsock= dsock;  }   public void run()  {   try   {    while(true)    {      byte[] dataBuf = new byte[1024];      DatagramPacket dataPack = new DatagramPacket(dataBuf,dataBuf.length);      dsock.receive(dataPack); //将获取的数据保存到指定的数据包      String ip = dataPack.getAddress().getHostAddress();      String data = new String(dataPack.getData(),0,dataPack.getLength());      int port = dataPack.getPort();      System.out.println();       System.out.println("来自ip为 "+ip+" <对方端口>: "+port+" 的消息");      System.out.println(data);        }   }   catch(Exception e)   {    throw new RuntimeException("接受失败!");   }   finally   {    dsock.close();   }  } }