Java Socket实现的一个简易聊天室

大体思路：用一个ServerSocket来接收所有Client的消息，然后转发给其他Client。在Server端，每个Client对应一个ServerHandleThread线程。在Client端，开一个线程来接收Server端的消息，main线程来接收键盘的输入。具体细节见代码。

Server端代码

import java.io.IOException;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {

    public static void main(String args[]) {
        try {
            ServerSocket serverSocket = new ServerSocket(4710);
            while (true) {
                Socket socket = serverSocket.accept();
                new ServerHandleThread(socket);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

ServerHandleThread代码

import java.io.*;
import java.net.Socket;
import java.util.ArrayList;
import java.util.List;

public class ServerHandleThread extends Thread {

    static List<ServerHandleThread> mServerHandleThreadList = new ArrayList<>();

    private Socket mSocket;
    private BufferedReader mBufferedReader;
    private PrintWriter mPrintWriter;
    private String mClientNickname;

    public ServerHandleThread(Socket socket) {
        mSocket = socket;
        start();
    }

    @Override
    public void run() {
        try {
            mBufferedReader = new BufferedReader(
                new InputStreamReader(mSocket.getInputStream()));
            mPrintWriter = new PrintWriter(
                new OutputStreamWriter(mSocket.getOutputStream()));
            mPrintWriter.println("请输入昵称！");
            mPrintWriter.flush();
            mClientNickname = mBufferedReader.readLine();
            mServerHandleThreadList.add(this);
            sendMsgToAll(mClientNickname + "加入聊天室");
        } catch (IOException e) {
            e.printStackTrace();
        }
        while (true) {
            try {
                String s = mBufferedReader.readLine();
                if (s.equals("bye!")) {
                    sendMsgToAll(mClientNickname + "退出了聊天室");
                    mPrintWriter.println(s);
                    mPrintWriter.flush();
                    mBufferedReader.close();
                    mPrintWriter.close();
                    mSocket.close();
                    break;
                }
                for (int i = 0;i < mServerHandleThreadList.size();i++) {
                    if (!mServerHandleThreadList.get(i).getClientNickname().equals(
                        mClientNickname)) {
                        mServerHandleThreadList.get(i).getPrintWriter().println(
                            mClientNickname + "：" + s);
                        mServerHandleThreadList.get(i).getPrintWriter().flush();
                    } else {
                        mServerHandleThreadList.get(i).getPrintWriter().println("Me：" + s);
                        mServerHandleThreadList.get(i).getPrintWriter().flush();
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    void sendMsgToAll(String msg) {
        for (int i = 0;i < mServerHandleThreadList.size();i++) {
            mServerHandleThreadList.get(i).getPrintWriter().println(msg);
            mServerHandleThreadList.get(i).getPrintWriter().flush();
        }
    }

    public PrintWriter getPrintWriter() {
        return mPrintWriter;
    }

    public String getClientNickname() {
        return mClientNickname;
    }
}

ClientOne代码

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

public class ClientOne {

    private static boolean flag = true;

    public static void main(String[] args) {
        BufferedReader mBufferedReader;
        PrintWriter mPrintWriter;
        try {
            Socket socket = new Socket("localhost", 4710);
            mBufferedReader = new BufferedReader(
                new InputStreamReader(socket.getInputStream()));
            mPrintWriter = new PrintWriter(
                new OutputStreamWriter(socket.getOutputStream()));
            new Thread(new Runnable() {
                @Override
                public void run() {
                    while (flag) {
                        try {
                            String s = mBufferedReader.readLine();
                            System.out.println(s);
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }).start();
            Scanner scanner = new Scanner(System.in);
            String s = scanner.nextLine();
            while (!s.equals("bye!")) {
                mPrintWriter.println(s);
                mPrintWriter.flush();
                s = scanner.nextLine();
            }
            mPrintWriter.println(s);
            mPrintWriter.flush();
            mBufferedReader.close();
            mPrintWriter.close();
            socket.close();
            scanner.close();
            flag = false;
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

}

至于ClientTwo，ClientThree之类的，改个类名就可以了。