java 实现socket基于UDP的双机通讯

UDP提供了无连接通信，且不对传送数据包进行可靠性保证，适合于一次传输少量数据，UDP传输的可靠性由应用层负责。由于数据量小且不保证可靠性，适合即时通讯功能；

源代码已上传我的资源页http://download.csdn.net/detail/u012373815/8953825

实现代码如下：

import java.awt.BorderLayout;

import java.awt.Color;

import java.awt.FlowLayout;

import java.awt.event.ActionEvent;

import java.awt.event.ActionListener;

import java.net.DatagramPacket;

import java.net.DatagramSocket;

import java.net.InetAddress;

import java.net.InetSocketAddress;

import javax.swing.JButton;

import javax.swing.JFrame;

import javax.swing.JOptionPane;

import javax.swing.JPanel;

import javax.swing.JScrollPane;

import javax.swing.JTextArea;

import javax.swing.JTextField;

import javax.swing.JLabel;

/*

 * author yang 2015 7 7udp

 */

publicclassGuiChatextends JFrame{

   privatestaticintDEFULT_PORT ; 

   private JLabelstateLB;

   private JTextAreacenterTextArea ,inputTextArea;

   private JPanelsouthPanel,bottompanel;

   private JTextFieldipTextField,remotePortTF;

   private JButtonsendBT,clearBT;

   private DatagramSocketdatagramSocket;

 

   publicvoid setUpUI(){

      setTitle("客户端");

      setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

      setSize(400,400);

      setResizable(false); //窗口大小不可调整

      setLocationRelativeTo(null);//窗口剧中

      stateLB =new JLabel("当前监听还未启动");

      stateLB.setHorizontalAlignment(JLabel.RIGHT);

      //窗口的center部分

      centerTextArea=new JTextArea();

      centerTextArea.setEditable(false);

      centerTextArea.setBackground(new Color(211, 211, 211));

      //窗口的SHOTU部分

      southPanel =new JPanel(new  BorderLayout());

      inputTextArea=new JTextArea(5,20);

      bottompanel=new JPanel(new FlowLayout(FlowLayout.CENTER,5,5));

      ipTextField=new JTextField("127.0.0.1",8);

 

      try {//输入本机端口号

         DEFULT_PORT=Integer.parseInt(JOptionPane.showInputDialog(this,"请输入客户端的端口号","端口号",JOptionPane.QUESTION_MESSAGE));

      if(DEFULT_PORT<1||DEFULT_PORT>65535)        

      {

        thrownew RuntimeException("端口号超出范围");

      }

      }catch(Exception e) {

        // TODO: handle exception

        JOptionPane.showMessageDialog(GuiChat.this,"你输入的端口号不正确，请输入1~65535之间的数");

      }

 

      remotePortTF=new JTextField(String.valueOf(DEFULT_PORT),3);  

      remotePortTF.setEditable(false);

      sendBT=new JButton("发送");

      clearBT=new JButton("清屏");

      bottompanel.add(ipTextField);

 

      bottompanel.add(remotePortTF);

      bottompanel.add(sendBT);

      bottompanel.add(clearBT);

      southPanel.add(new JScrollPane(inputTextArea),BorderLayout.CENTER);

      southPanel.add(bottompanel,BorderLayout.SOUTH);

     

      add(stateLB,BorderLayout.NORTH);

      add(new JScrollPane(centerTextArea),BorderLayout.CENTER);

      add(southPanel,BorderLayout.SOUTH);

      setVisible(true);

   }

  

   publicvoid setListener(){

   sendBT.addActionListener(new ActionListener() {

     

      @Override

      publicvoidactionPerformed(ActionEvent e) {

        // TODO Auto-generated method stub

      final String ipaddress=ipTextField.getText();

      final String remoteport=remotePortTF.getText();

  

      if(ipaddress==null||remoteport.trim().equals(""))

      {

        JOptionPane.showMessageDialog(GuiChat.this,"请输入IP地址和端口号");

        return ;

      }

     

      Stringsendcontent=inputTextArea.getText();

      byte []buf=sendcontent.getBytes();

      try {

        centerTextArea.append("我对"+ipaddress+":"+remoteport+"说:\n"+inputTextArea.getText()+"\n\n");

         centerTextArea.setCaretPosition(centerTextArea.getText().length());

       

        datagramSocket.send(new DatagramPacket(buf,buf.length,

         InetAddress.getByName(ipaddress),Integer.parseInt(remoteport)));

        inputTextArea.setText("");

      }catch(Exception e2) {

        // TODO: handle exception

        JOptionPane.showMessageDialog(GuiChat.this,"出错了发送不成功");

        e2.printStackTrace();

      }

     

      clearBT.addActionListener(new ActionListener() {

       

        @Override

        publicvoidactionPerformed(ActionEvent e) {

           centerTextArea.setText("");//清空聊天记录

        }

      });     

      }

   });

}

//填写程序监听的端口号

   publicvoid initSocket(){

   int  port=DEFULT_PORT;

   while(true)

   {

      try {

        if(datagramSocket!=null&&!datagramSocket.isClosed())

        {

           datagramSocket.isClosed();

        }

        try {

           port=Integer.parseInt(JOptionPane.showInputDialog(this,"请输入要监听的端口号","端口号",JOptionPane.QUESTION_MESSAGE));

        if(port<1||port>65535)        

        {

           thrownew RuntimeException("端口号超出范围");

        }

        }catch(Exception e) {

           // TODO: handle exception

           JOptionPane.showMessageDialog(GuiChat.this,"你输入的端口号不正确，请输入1~65535之间的数");

           continue;

        }

        datagramSocket=new DatagramSocket(port);

        startListen();

        stateLB.setText("已在"+port+"端口监听");

        break;

      }catch(Exception e) {

        // TODO: handle exception

        JOptionPane.showMessageDialog(GuiChat.this,"端口号已被占用，请重新设置端口");

           stateLB.setText("当前还未启动监听");

      }

   }

}

 

   publicvoid startListen(){

   new Thread(){

      private DatagramPacketp;

      @Override

      publicvoid run() {

        // TODO Auto-generated method stub

        byte [] buf=newbyte[1024];

        p=new DatagramPacket(buf,buf.length);

        while(!datagramSocket.isClosed())

        {

           try {

              datagramSocket.receive(p);

              centerTextArea.append(p.getAddress().getHostAddress()+":"

                    +((InetSocketAddress)

                    p.getSocketAddress()).getPort()+"对我说：\n"

                    +new String(p.getData(),0,p.getLength())+"\n\n");

              centerTextArea.setCaretPosition(centerTextArea.getText().length());

           }catch(Exception e) {

              // TODO: handle exception

           }

        }

       

      }

   }.start();

   }

}

启动程序  客户端的端口号不能相同，且必须两个端口互为监听才能保证通话

publicclassCreatGUI{

  

   publicstaticvoid main(String[] args) {     

       GuiChat ch=new GuiChat();

       ch.setUpUI();

       ch.initSocket();

       ch.setListener();

   }

 

}