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登录案例

服务器端

package com.company;

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

public class Server {

    /**
     * 基于TCP协议的Socket通信，实现用户登录
     * 服务器端
     * @param args
     */
    public static void main(String[] args) {
        try {
            //1、创建服务器Socket，指定端口
            ServerSocket serverSocket = new ServerSocket(8888);
            //2、使用accept监听，等待客户端连接，处于阻塞状态
            System.out.println("服务端即将启动，等待客户连接。。。");
            Socket acceptSocket = serverSocket.accept();

            //3、获取输入流读取客户端发送的信息
            InputStream inputStream = acceptSocket.getInputStream();

            BufferedReader br=new BufferedReader(new InputStreamReader(inputStream));
            String line=null;
            while ((line=br.readLine())!=null){
                System.out.println("我是服务器，客户端说："+line);
            }
            acceptSocket.shutdownInput();

            //4、响应客户端的请求
            OutputStream outputStream = acceptSocket.getOutputStream();
            BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(outputStream));
            bw.write("欢迎您！");
            bw.flush();
            acceptSocket.shutdownOutput();

            //5、关闭资源
            br.close();
            bw.close();
            acceptSocket.close();
            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

客户端

package com.company;

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

public class Client {

    public static void main(String[] args) {
        try {
            //1、创建客户端socket，指定服务器地址和端口
            Socket socket = new Socket("localhost",8888);
//            Socket socket = new Socket("127.0.0.1",8888);
            //2、获取输出流，发送信息
            OutputStream outputStream = socket.getOutputStream();

            BufferedWriter bw=new BufferedWriter(new OutputStreamWriter(outputStream));
            bw.write("admin;123");
            bw.flush();
            socket.shutdownOutput();


            //3、获取服务器端的信息，并响应
            InputStream inputStream = socket.getInputStream();
            BufferedReader br=new BufferedReader(new InputStreamReader(inputStream));
            String line=null;
            while ((line=br.readLine())!=null){
                System.out.println("已收到服务器端的回复："+line);
            }
            socket.shutdownInput();


            //4、关闭资源
            bw.close();
            br.close();
            socket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

多线程实现服务器端

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修改服务端

package com.company;

import java.io.*;
import java.net.InetAddress;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {

    /**
     * 基于TCP协议的Socket通信，实现用户登录
     * 服务器端
     * @param args
     */
    public static void main(String[] args) {
        try {
            //1、创建服务器Socket，指定端口
            ServerSocket serverSocket = new ServerSocket(8888);
            Socket acceptSocket=null;
            System.out.println("服务端即将启动，等待客户连接。。。");

            int count=0;

            //死循环
            while (true){
                //2、使用accept监听，等待客户端连接，处于阻塞状态,
                // 阻塞时不会循环，当有客户端连接时循环继续
                acceptSocket = serverSocket.accept();
                new ServerThread(acceptSocket).run();
                count++;//统计客户端数量
                System.out.println("客户端的数量为"+count);

                InetAddress address=acceptSocket.getInetAddress();
                System.out.println("当前客户端IP地址为："+address.getHostAddress());

            }

//            //死循环代码无法跑到这
//            serverSocket.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

线程

package com.company;

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

public class ServerThread extends Thread {

    //和本线程相关的Socket
    Socket mSocket = null;

    public ServerThread(Socket socket) {
        mSocket = socket;
    }

    //执行线程，响应客户端
    @Override
    public void run() {
        BufferedReader br = null;
        BufferedWriter bw = null;
        //3、获取输入流读取客户端发送的信息
        InputStream inputStream = null;
        try {
            inputStream = mSocket.getInputStream();


            br = new BufferedReader(new InputStreamReader(inputStream));
            String line = null;
            while ((line = br.readLine()) != null) {
                System.out.println("我是服务器，客户端说：" + line);
            }
            mSocket.shutdownInput();

            //4、响应客户端的请求
            OutputStream outputStream = mSocket.getOutputStream();
            bw = new BufferedWriter(new OutputStreamWriter(outputStream));
            bw.write("欢迎您！");
            bw.flush();
            mSocket.shutdownOutput();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            //5、关闭资源
            if (br != null) {

                try {
                    br.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (bw != null) {

                try {
                    bw.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if (mSocket != null) {

                try {
                    mSocket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

    }
}