(JAVA) TCP receive and send data

1. TCP send data steps

TCP发送数据的步骤：
    1.创建客户端的Socket对象
    2.获取输出流，写数据
    3.释放资源

2. Send data program code

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

public class ClientDemo {
    
    
    public static void main(String[] args) throws IOException {
    
    
        //1.创建客户端的Socket对象
        //Socket​(String host, int port) 创建流套接字并将其连接到指定主机上的指定端口号。
        Socket s = new Socket("zshao",10001);

        //2.获取输出流，写数据
        //OutputStream getOutputStream​() 返回此套接字的输出流。
        OutputStream os = s.getOutputStream();
        os.write("hello,tpc".getBytes());

        //3.释放资源
        s.close();
    }
}

3. TCP receive data steps

TCP接收数据的步骤
    1.创建服务器端的Socket对象
    2.监听客户端的连接，返回一个Socket对象
    3.获取输入流，读数据，并把数据显示在控制台上
    4.释放资源

4. Receive data code

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

public class ServerDemo {
    
    
    public static void main(String[] args) throws IOException {
    
    
        //1.创建服务器端的Socket对象
        //ServerSocket​(int port) 创建绑定到指定端口的服务器套接字。
        ServerSocket ss = new ServerSocket(10001);

        //2.监听客户端的连接，返回一个Socket对象
        //Socket accept​() 侦听要连接到此套接字并接受它。
        Socket s = ss.accept();

        //3.获取输入流，读数据，并把数据显示在控制台上
        InputStream is = s.getInputStream();
        byte [] bys = new byte[1024];
        int len;
        while ((len=is.read(bys))!=-1){
    
    
            System.out.println("数据是："+ new String(bys,0,len));
        }
        
        //4.释放资源
        ss.close();
    }
}

5. Program running results

First open the running receiving program to wait for sending, and then run the sending program, the result is shown as follows:

6. Visualize memory

To facilitate memory, I thought of a metaphor.
Assume that TCP communication is the communication between two cities in ancient times.
Sender to send messengers to send information, so we must first create a messenger ( the Socket ) objects, messenger to know exactly to what cities ( IP ) of which door ( Port ), then the messenger carrying information out of the city ( OutputStream ), a finish to Close the city gate ( close ).
The recipient is another city. First open the corresponding door ( ServerSocket ), the person who receives the letter from the door ( Socket s = ss.accept() ), then accept the message ( InputStream ), and finally close the city gate ( close ).