import java.io.*;

import java.net.Inet4Address;

import java.net.InetSocketAddress;

import java.net.Socket;

public class Client {

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

        Socket socket = new Socket();

        // 超时时间

        socket.setSoTimeout(3000);

        // 连接本地，端口2000；超时时间3000ms

        socket.connect(new InetSocketAddress(Inet4Address.getLocalHost(), 2000), 3000);

        System.out.println("已发起服务器连接，并进入后续流程～");

        System.out.println("客户端信息：" + socket.getLocalAddress() + " P:" + socket.getLocalPort());

        System.out.println("服务器信息：" + socket.getInetAddress() + " P:" + socket.getPort());

        try {

            // 发送接收数据

            todo(socket);

        } catch (Exception e) {

            System.out.println("异常关闭");

        }

        // 释放资源

        socket.close();

        System.out.println("客户端已退出～");

    }

    private static void todo(Socket client) throws IOException {

        // 构建键盘输入流

        InputStream in = System.in;

        BufferedReader input = new BufferedReader(new InputStreamReader(in));

        // 得到Socket输出流，并转换为打印流

        OutputStream outputStream = client.getOutputStream();

        PrintStream socketPrintStream = new PrintStream(outputStream);

        // 得到Socket输入流，并转换为BufferedReader

        InputStream inputStream = client.getInputStream();

        BufferedReader socketBufferedReader = new BufferedReader(new InputStreamReader(inputStream));

        boolean flag = true;

        do {

            // 键盘读取一行

            String str = input.readLine();

            // 发送到服务器

            socketPrintStream.println(str);

            // 从服务器读取一行

            String echo = socketBufferedReader.readLine();

            if ("bye".equalsIgnoreCase(echo)) {

                flag = false;

            }else {

                System.out.println(echo);

            }

        }while (flag);

        // 资源释放

        socketPrintStream.close();

        socketBufferedReader.close();

    }

}

import java.io.BufferedReader;

import java.io.IOException;

import java.io.InputStreamReader;

import java.io.PrintStream;

import java.net.ServerSocket;

import java.net.Socket;

public class Server {

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

        ServerSocket server = new ServerSocket(2000);

        System.out.println("服务器准备就绪～");

        System.out.println("服务器信息：" + server.getInetAddress() + " P:" + server.getLocalPort());

        // 等待客户端连接

        for (; ; ) {

            // 得到客户端

            Socket client = server.accept();

            // 客户端构建异步线程

            ClientHandler clientHandler = new ClientHandler(client);

            // 启动线程

            clientHandler.start();

        }

    }

    /**

     * 客户端消息处理

     */

    private static class ClientHandler extends Thread {

        private Socket socket;

        private boolean flag = true;

        ClientHandler(Socket socket) {

            this.socket = socket;

        }

        @Override

        public void run() {

            super.run();

            System.out.println("新客户端连接：" + socket.getInetAddress() +

                    " P:" + socket.getPort());

            try {

                // 得到打印流，用于数据输出；服务器回送数据使用

                PrintStream socketOutput = new PrintStream(socket.getOutputStream());

                // 得到输入流，用于接收数据

                BufferedReader socketInput = new BufferedReader(new InputStreamReader(

                        socket.getInputStream()));

                do {

                    // 客户端拿到一条数据

                    String str = socketInput.readLine();

                    if ("bye".equalsIgnoreCase(str)) {

                        flag = false;

                        // 回送

                        socketOutput.println("bye");

                    } else {

                        // 打印到屏幕。并回送数据长度

                        System.out.println(str);

                        socketOutput.println("回送：" + str.length());

                    }

                } while (flag);

                socketInput.close();

                socketOutput.close();

            } catch (Exception e) {

                System.out.println("连接异常断开");

            } finally {

                // 连接关闭

                try {

                    socket.close();

                } catch (IOException e) {

                    e.printStackTrace();

                }

            }

            System.out.println("客户端已退出：" + socket.getInetAddress() +

                    " P:" + socket.getPort());

        }

    }

}