Java基于UDP协议实现简单的聊天室程序

package com.tsr.simplechat.receive_server;

import java.io.IOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.SocketException;
import java.util.ArrayList;
import java.util.HashMap;

import com.google.gson.Gson;
import com.tsr.simplechat.bean.MessageEntity;
import com.tsr.simplechat.client.ChatClient;

//聊天服务器
public class ChatServer extends Thread {
 // 程序占用端口号
 private static final int PORT = 10000;
 // 消息接受套接字对象
 private static DatagramSocket server = null;
 // 字典对象(Key：聊天室ID，Value：该聊天室下的客户端用户集合);
 private static HashMap<String, ArrayList<ChatClient>> groups = new HashMap<String, ArrayList<ChatClient>>();

 // 构造器
 public ChatServer() {
 try {
  // 消息接受套接字对象的构造初始化
  server = new DatagramSocket(PORT);
 } catch (SocketException e) {
  e.printStackTrace();
 }
 }

 // 注册聊天室新登录用户
 public static void logInGroup(String groupID, ChatClient client) {
 // 通过聊天室ID，获取该聊天室的所有在线用户
 ArrayList<ChatClient> clients = groups.get(groupID);
 if (clients == null) {
  clients = new ArrayList<ChatClient>();
 }
 // 将此次进入聊天室的用户登记
 clients.add(client);
 // 更新聊天室信息
 groups.put(groupID, clients);
 }

 // 循环接收消息
 @Override
 public void run() {
 while (true) {
  receiveMessage();
 }
 }

 private void receiveMessage() {
 // UDP数据包
 byte[] buf = new byte[1024];
 DatagramPacket packet = new DatagramPacket(buf, buf.length);
 while (true) {
  try {
  // 接受数据包
  server.receive(packet);
  } catch (IOException e) {
  // TODO Auto-generated catch block
  e.printStackTrace();
  }

  // 解析数据包，获取聊天信息
  String content = new String(packet.getData(), 0, packet.getLength());

  // 通过第三方包解析json数据
  Gson gson = new Gson();
  MessageEntity me = gson.fromJson(content, MessageEntity.class);

  // 解析消息内容，通过聊天室ID，获取该聊天室的所有在线用户
  ArrayList<ChatClient> clients = groups.get(me.getGroupId());

  // 将接收到的消息推送回该聊天室的各个用户
  for (ChatClient client : clients) {
  client.pushBackMessage(me);
  }
 }
 }
}

 package com.tsr.simplechat.client;

import java.awt.Button;
import java.awt.Event;
import java.awt.Frame;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
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 com.tsr.simplechat.bean.MessageEntity;
import com.tsr.simplechat.receive_server.ChatServer;

//客户端程序
public class ChatClient extends Frame {
 private static final long serialVersionUID = 1L;
 // 聊天室ID
 private String groupID;
 // 客户端用户名
 private String clientName;
 // 客户端消息发送服务套接字
 private DatagramSocket msg_send;
 // 服务端口
 private final int PORT = 10000;
 // 服务器IP地址
 private InetAddress ip;

 // 客户端控件
 TextField tf = new TextField(20);
 TextArea ta = new TextArea();
 Button send = new Button("send");

 // 客户端构造器
 public ChatClient(String groupID, String clientName) {

 super("聊天室:" + groupID + "/" + clientName);
 this.clientName = clientName;
 this.groupID = groupID;
 // 设置客户端界面样式
 add("North", tf);
 add("Center", ta);
 add("South", send);
 setSize(250, 250);
 show();
 // 聊天相关服务器初始化
 init();

 // 监视器
 addWindowListener(new WindowAdapter() {
  public void windowClosing(WindowEvent e) {
  // 关闭消息发送服务
  msg_send.close();
  // 关闭客户端程序
  dispose();
  System.exit(0);
  }
 });

 }

 // 聊天相关服务器初始化
 private void init() {
 // 注册当前用户及所在聊天室信息注册到服务器
 ChatServer.logInGroup(groupID, this);
 try {
  // 初始化消息发送套接字对象
  msg_send = new DatagramSocket();
  // 指定消息服务器
  try {
  ip = InetAddress.getByName("127.0.0.1");
  } catch (UnknownHostException e) {
  System.out.println("未知的主机异常..");
  }
 } catch (SocketException e) {
  System.out.println("套接字连接异常..");
 }
 }

 // 消息发送按钮时间监听
 public boolean action(Event evt, Object arg) {
 if (evt.target.equals(send)) {
  try {
  // 获取输入内容
  String content = tf.getText();
  // 发送消息
  send_message(content);
  // 清空聊天框
  tf.setText(null);
  } catch (Exception ioe) {
  System.out.print(ioe.getMessage());
  }
 }
 return true;
 }

 // 消息发送
 private void send_message(String content) {
 // 消息格式化(json格式)
 String message = messageFormat(content);
 // 将消息封装成UDP数据包
 byte[] buf = message.getBytes();
 DatagramPacket packet = new DatagramPacket(buf, buf.length, ip, PORT);

 try {
  // 通过UDP协议发送消息
  msg_send.send(packet);
 } catch (IOException e) {
  System.out.println("IO异常..");
 }
 }

 // 消息格式化
 private String messageFormat(String content) {
 StringBuffer buffer = new StringBuffer();
 buffer.append("{\"groupId\":").append("\"").append(groupID).append(
  "\",");
 buffer.append("\"userName\":\"").append(clientName).append("\",");
 buffer.append("\"text\":\"").append(content).append("\"}");

 return buffer.toString();

 }

 // 从服务器获取当前聊天室最新消息(回调..)
 public void pushBackMessage(MessageEntity me) {
 ta.append(me.getUserName() + ":" + me.getText());
 ta.append("\n");

 }
}

 package com.tsr.simplechat.bean;

//消息实体
public class MessageEntity {
 private String groupId;
 private String userName;
 private String text;

 public String getGroupId() {
 return groupId;
 }

 public void setGroupId(String groupId) {
 this.groupId = groupId;
 }

 public String getUserName() {
 return userName;
 }

 public void setUserName(String userName) {
 this.userName = userName;
 }

 public String getText() {
 return text;
 }

 public void setText(String text) {
 this.text = text;
 }

}

 import com.tsr.simplechat.client.ChatClient;
import com.tsr.simplechat.receive_server.ChatServer;

public class Test {
 public static void main(String[] args) {
 ChatServer r = new ChatServer();
 r.start();
 
 ChatClient c1 = new ChatClient("001", "小红");
 ChatClient c2 = new ChatClient("001", "小绿");
 ChatClient c3 = new ChatClient("002", "小黑");
 }
}