java写局域网程序 java局域网聊天程序

  前段时间学到Socket套接字，对tcp/ip通信很感兴趣，便想编写测试下，很是简单。写到博客上分享下，最重要的是有一些不明白的问题希望有人给予解答。本实例采用DatagramSocket、DatagramPacket通信，指定目标IP地址即可发送信息，可向局域网外的公网IP主机发信息，如何接受来自公网IP的信息？如何穿透路由器到达指定内网IP主机？

  设计思路：需要GUI组件简单设计个页面；局域网通信，用tcp通信，client对client，所以只编写一个client就好了；client之间通信用DatagramSocket、DatagramPacket收发数据包，同时用多线程分别封装发送数据包，接收数据包；最后解析数据包，用IO流解析得到的信息，显示在文本区。

页面：

过于简单直接发代码：

import java.awt.BorderLayout;
 
 
import java.awt.Dimension;
 
 
import java.awt.event.ActionEvent;
 
 
import java.awt.event.ActionListener;
 
 
import java.io.IOException;
 
 
import java.net.DatagramPacket;
 
 
import java.net.DatagramSocket;
 
 
import java.net.InetAddress;
 
 
import java.net.SocketException;
 
 
import java.net.UnknownHostException;
 
 
import java.text.DateFormat;
 
 
import java.text.SimpleDateFormat;
 
 
import java.util.Date;
 
 

 
 
import javax.swing.JButton;
 
 
import javax.swing.JFrame;
 
 
import javax.swing.JLabel;
 
 
import javax.swing.JPanel;
 
 
import javax.swing.JScrollPane;
 
 
import javax.swing.JTextArea;
 
 
import javax.swing.JTextField;
 
 
import javax.swing.*;
 
 

 
 
public class chat
 
 
{
 
 
private JLabel ipjl;
 
 
private JLabel portjl;
 
 
private JTextField ipjtf;
 
 
private JTextField portjtf;
 
 
private JScrollPane messagejs;
 
 
private JScrollPane sendjs;
 
 
private JTextArea messagejta;
 
 
private JTextArea sendjta;
 
 
private JButton sendjb;
 
 
private DatagramSocket dgssend;
 
 
private DatagramSocket dgsrece;
 
 
private DatagramPacket dgp;
 
 
private String message;
 
 
private String readmessage;
 
 
private InetAddress ip;
 
 
private int port;
 
 
	
 
 
public chat() throws IOException
 
 
{
 
 
dgssend = new DatagramSocket();
 
 
dgsrece = new DatagramSocket(8888);
 
 
dgp = null;
 
 
message = null;
 
 
creatFrame();
 
 
readmessages sm = new readmessages();
 
 
Thread t = new Thread(sm);
 
 
t.start();
 
 
		
 
 
		
 
 
		
 
 
}
 
 
public void creatFrame()
 
 
{
 
 
JFrame chatroom = new JFrame("聊天");
 
 
chatroom.setLayout(new BorderLayout());
 
 
chatroom.setBounds(650, 200, 800, 680);
 
 
JPanel north = new JPanel();
 
 
JPanel center = new JPanel();
 
 
JPanel south = new JPanel();
 
 
north.setPreferredSize(new Dimension(820,80));
 
 
south.setPreferredSize(new Dimension(820,160));
 
 
chatroom.add(north,BorderLayout.NORTH);
 
 
chatroom.add(center);
 
 
chatroom.add(south,BorderLayout.SOUTH);
 
 
		
 
 
		
 
 
ipjl = new JLabel("对方IP地址");
 
 
ipjtf = new JTextField("",15);
 
 
portjl = new JLabel("对方端口");
 
 
portjtf = new JTextField("8888",15);
 
 
		
 
 
messagejta = new JTextArea("",20,70);
 
 
messagejs = new JScrollPane(messagejta);
 
 
messagejta.setEditable(false);
 
 
		
 
 
sendjta = new JTextArea("",6,70);
 
 
sendjs = new JScrollPane(sendjta);
 
 
sendjb = new JButton("发送");
 
 
sendjb.addActionListener(new sendmessage());
 
 
		
 
 
north.add(ipjl);
 
 
north.add(ipjtf);
 
 
north.add(portjl);
 
 
north.add(portjtf);
 
 
		
 
 
center.add(messagejs);
 
 
		
 
 
south.add(sendjs);
 
 
south.add(sendjb);
 
 
		
 
 
chatroom.setVisible(true);
 
 
chatroom.setDefaultCloseOperation(chatroom.EXIT_ON_CLOSE);
 
 

 
 
}
 
 
class sendmessage implements ActionListener {
 
 

 
 
@Override
 
 
public void actionPerformed(ActionEvent arg0) {
 
 
try{
 
 
message = sendjta.getText();
 
 
ip = InetAddress.getByName(ipjtf.getText());
 
 
port = Integer.parseInt(portjtf.getText());
 
 
dgp = new DatagramPacket(message.getBytes(),message.getBytes().length,ip,port);
 
 
			
 
 
Date date = new Date();
 
 
DateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
 
 
messagejta.append("我: " +format.format(date) + '\n');
 
 
messagejta.append( message +" "+ '\n');
 
 
            
 
 
//			messagejta.setText(messagejta.getText()+"\r\n"+"我："+message+"\r\n");
 
 
dgssend.send(dgp);
 
 
sendjta.setText("");
 
 
			
 
 
}catch(Exception e)
 
 
{e.printStackTrace();}
 
 
}
 
 

 
 
}
 
 

 
 
class readmessages implements Runnable
 
 
{
 
 

 
 
@Override
 
 
public void run() {
 
 
			
 
 
while(true)
 
 
{
 
 
try{
 
 
					
 
 
byte[] buf = new byte[1024];
 
 
DatagramPacket dgpread = new DatagramPacket(buf,buf.length);
 
 
dgsrece.receive(dgpread);
 
 
String readmessage = new String(dgpread.getData(),0,dgpread.getLength());
 
 
//					ipjtf.setText(dgpread.getAddress().toString());
 
 
//					portjtf.setText(dgpread.getPort()+"");
 
 
					
 
 
Date date = new Date();
 
 
DateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
 
 
messagejta.append(dgpread.getAddress().toString()+": " +format.format(date) + '\n');
 
 
messagejta.append( readmessage + '\n');
 
 
		              
 
 
//					messagejta.setText(messagejta.getText()+"\r\n"+dgpread.getAddress().toString()+":"+readmessage);
 
 
					
 
 
}
 
 
catch(Exception e)
 
 
{e.getStackTrace();}
 
 
}
 
 
			
 
 
}
 
 
		
 
 
}
 
 

 
 
public static void main(String[] args) throws IOException
 
 
{
 
 
// TODO Auto-generated method stub
 
 
new chat();
 
 
}
 
 

 
 
}