Java多人聊天室第一版

 package cn.zhang.chat;

 import java.io.BufferedReader;
 import java.io.PrintWriter;

 /**
   * 所有用户均有的信息，单独设为一个类
  * @author
  *
  */

 public class Account {

     //封装，属性设为私有
     private String name;
     private BufferedReader reader;
     private PrintWriter writer;

     //设置相应的set和get方法
     public String getName() {
         return name;
     }

     public void setName(String name) {
         this.name = name;
     }

     public BufferedReader getReader() {
         return reader;
     }

     public void setReader(BufferedReader reader) {
         this.reader = reader;
     }

     public PrintWriter getWriter() {
         return writer;
     }

     public void setWriter(PrintWriter writer) {
         this.writer = writer;
     }
 }

 package cn.zhang.chat;

 import java.io.*;
 import java.net.Socket;
 import java.util.Scanner;

 public class ChatClient {

     public static void main(String[] args) throws Exception {
         Scanner sc = new Scanner(System.in);

         while (true) {
             System.out.print("请输入昵称：");
             String name = sc.nextLine();

             Socket s = new Socket(UserData.HOST, UserData.PORT);
             InputStream in = s.getInputStream();
             OutputStream out = s.getOutputStream();

             BufferedReader reader = new BufferedReader(new InputStreamReader(in));
             PrintWriter writer = new PrintWriter(new OutputStreamWriter(out), true);

             writer.println(name);
             String temp = reader.readLine();
             if (temp.equals("success")) {
                 // 启动新线程监听消息
                 Account user = new Account();
                 user.setReader(reader);
                 user.setWriter(writer);
                 user.setName(name);
                 ReceiveMessage rm = new ReceiveMessage(user);
                 new Thread(rm).start();

                 // 给服务器发消息
                 while (true) {

                     String msg = sc.nextLine();
                     writer.println(msg);

                 }

             } else {

                 System.out.println(temp);

             }
         }
     }
 }

 package cn.zhang.chat;

 import java.io.*;
 import java.net.ServerSocket;
 import java.net.Socket;
 /**
   * 服务器端的ChatServer
  * @author
  *
  */
 public class ChatServer {

     public static void main(String[] args) throws Exception {

         //等待用户连接之前，创建一个SeverSocket
         ServerSocket ss = new ServerSocket(UserData.PORT);

         while (true) {
             System.out.println("等待链接");
             Socket s = ss.accept();

             InputStream in = s.getInputStream();
             OutputStream out = s.getOutputStream();

             BufferedReader reader = new BufferedReader(new InputStreamReader(in));
             PrintWriter writer = new PrintWriter(new OutputStreamWriter(out), true);

             String name = reader.readLine();//读入名字

             boolean flag = false;

             //foreach循环遍历名字，若名字相同，则返回用户名已存在
             for (Account a : UserData.USERS) {
                 if (a.getName().equals(name)) {
                     flag = true;
                 }
             }
             if (flag) {
                 writer.println("用户名已存在~~~");
             } else {
                 writer.println("success");
             }

             // 启动一个新的线程监听消息
             Account user = new Account();
             user.setName(name);
             user.setWriter(writer);
             user.setReader(reader);

             SendMessage sm = new SendMessage(user);
             new Thread(sm).start();

             UserData.USERS.add(user);
             for (Account a : UserData.USERS) {
                 a.getWriter().println("[" + name + "]进入聊天室，当前在线人数：" + UserData.USERS.size());
             }
         }

     }

 }

 package cn.zhang.chat;

 public class ReceiveMessage implements Runnable {

     private Account user;

     public ReceiveMessage(Account user) {
         this.user = user;
     }

     @Override
     public void run() {
         while (true) {
             try {
                 String msg = this.user.getReader().readLine();
                 System.out.println(msg);
             } catch (Exception e) {
                 e.printStackTrace();
             }
         }
     }
 }

 package cn.zhang.chat;

 import java.io.IOException;

 public class SendMessage implements Runnable {

     private Account user;

     public SendMessage(Account user) {
         this.user = user;
     }

     //重写父类方法
     @Override
     public void run() {
         while (true) {
             try {
                 String msg = this.user.getReader().readLine();
                 for (Account a : UserData.USERS) {
                     if (!a.getName().equals(this.user.getName())) {
                         a.getWriter().println(this.user.getName() + " 说：" + msg);
                     }
                 }

             } catch (Exception e) {
                 UserData.USERS.remove(this.user);
                 for (Account a : UserData.USERS) {
                     System.out.println("[" + this.user.getName() + "]退出了聊天室，当前在线人数：" + UserData.USERS.size());
                     a.getWriter().println("[" + this.user.getName() + "]退出了聊天室，当前在线人数：" + UserData.USERS.size());
                     break;
                 }

                 e.printStackTrace();
             }
         }
     }
 }

 package cn.zhang.chat;
 import java.util.ArrayList;
 import java.util.List;
 /**
   * 用户基本信息
  * @author
  *
  */
 public class UserData {

     public static final String HOST = "127.0.0.1";
     public static final int PORT = 8888;

     public static final List<Account> USERS = new ArrayList<>();

 }