20220525

服务端

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

public class TcpServerDemo2 {
    public static void main(String[] args) {
        try {
            System.out.println("=====TCP Server Started=====");

            ServerSocket ss = new ServerSocket(7777);
            
            Socket soc = ss.accept();
            
            InputStream is = soc.getInputStream();
            
            BufferedReader br = new BufferedReader(new InputStreamReader(is));

            String msg;//用来存消息的字符串变量
            if ((msg = br.readLine()) != null){
                System.out.println(soc.getRemoteSocketAddress()+"has send: "+msg);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

发送端

import java.io.OutputStream;
import java.io.PrintStream;
import java.net.Socket;

public class TcpClientDemo1 {
    public static void main(String[] args) throws Exception {
        System.out.println("=====TCP Client Started=====");

        //新建套接字对象，ip是对方IP，这里就是我本机，端口也是对方端口
        Socket soc = new Socket("127.0.0.1",7777);
        //套接字可以get一个字节输出流
        OutputStream os = soc.getOutputStream();
        //用打印流包装起来
        PrintStream ps = new PrintStream(os);

        ps.println("Are you ready?");
        ps.flush();

//        soc.close();
    }
}

服务端

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

public class TcpServerDemo2 {
    public static void main(String[] args) {
        System.out.println("====TCP Server Started====");
        Socket soc = new Socket();//这里新建soc是为了让catch语句可以读到

        try {
            ServerSocket ss = new ServerSocket(5555);
            soc = ss.accept();//这个accept方法会一直等待对方发送消息，soc本来可以在这里新建，但为了下线提示语句放到try上面了
            System.out.println(soc.getRemoteSocketAddress()+" he came~~~");
            //用Socket得到一个原始字节输入流
            InputStream is = soc.getInputStream();
            //缓冲字符输入流                               转换流
            BufferedReader br = new BufferedReader(new InputStreamReader(is));
            String msg;
            while ((msg = br.readLine()) != null){
                    System.out.println(soc.getRemoteSocketAddress()+" has sent: "+msg);
            }
            //如果对方关闭了socket，那么本方也会自动关闭，干净利落，如果对方没写soc.close(),会异常
        } catch (IOException e) {
//            e.printStackTrace();
            
            System.out.println(soc.getRemoteSocketAddress()+" he left~~~");

        }
    }
}

发送端

import java.io.IOException;
import java.io.OutputStream;
import java.io.PrintStream;
import java.net.Socket;
import java.util.Scanner;

public class TcpClientDemo1 {
    public static void main(String[] args) {
        System.out.println("====TCP Client Started====");

        try {
            Socket soc = new Socket("127.0.0.1",5555);
            //用socket得到一个原始字节输出流
            OutputStream os = soc.getOutputStream();
            //把原始字节输入流包装成打印流
            PrintStream ps = new PrintStream(os);

            Scanner sc = new Scanner(System.in);
            String msg;
            while (true){
                System.out.println("Input what are you want to send:");
                msg = sc.nextLine();
                if ("exit".equals(msg)){
                    break;
                }
                ps.println(msg);
                ps.flush();

            }
//            soc.close();//本例写这句，关闭soc之后，会话断开，对方也会断开，现象在控制台可见，干净利落，无异常，不写有

        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}