Detailed explanation of example code for one-way communication in Java

This article mainly introduces the method and related examples of one-way communication through sockets in Java network programming. It is an introductory program for network programming. Although it is simple, it has certain reference value. Friends in need can refer to it.

In network programming, if the client is only required to send messages to the server and the server is not required to send messages to the client, it is called single-line communication. After the client socket and server socket are successfully connected, it can be estimated that data is sent through the output stream, and the server receives data through the input stream. The following is an example of a simple one-way communication.

        Example 1: This example is a TCP server program, establish a server socket in the getserver() method, and call the getClienMessage() method to obtain client information. The code is as follows:

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

public class MyTcp {
	private BufferedReader reader;
	private ServerSocket server;
	private Socket socket;
	void getserver() {
		try {
			server = new ServerSocket(8998);
			System.out.println("服务器套接字已经创建成功");
			while(true) {
				System.out.println("等待客户机的连接");
				socket = server.accept();
				reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
				getClienMessage();
			}
		}catch(Exception e) {
			e.printStackTrace();
		}
		
	}
	private void getClienMessage() {
		try {
			while (true) {
				System.out.println("客户机："+ reader.readLine());
			}
		}catch(Exception e) {
			e.printStackTrace();
		}
		try {
			if(reader !=null) {
				reader.close();
			}
			if(socket !=null) {
				socket.close();
			}
		}catch(IOException e) {
			e.printStackTrace();
		}
	}
	public static void main(String[] args) {
		MyTcp tcp = new MyTcp();
		tcp.getserver();
	}
}

Run result:

The server socket has been created successfully
Waiting for client connection

Now let’s take a look at the client program.

Example 2: Client program to send the information entered by the user in the text box to the server, and display the information entered in the text box in the client's text field. The code is as follows:

import java.awt.BorderLayout;
import java.awt.Container;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.io.PrintWriter;
import java.net.Socket;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTextArea;
import javax.swing.JTextField;
import javax.swing.border.BevelBorder;

public class MyClien extends JFrame{
	private PrintWriter writer;
	Socket socket;
	private JTextArea ta = new JTextArea();
	private JTextField tf = new JTextField();
	Container cc;
	public MyClien(String title) {
		super(title);
		setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		cc = this.getContentPane();
		final JScrollPane scrollPane = new JScrollPane();
		scrollPane.setBorder(new BevelBorder(BevelBorder.RAISED));
		getContentPane().add(scrollPane, BorderLayout.CENTER);
		scrollPane.setViewportView(ta);
		cc.add(tf,"South");
		tf.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				writer.println(tf.getText());
				ta.append(tf.getText()+ '\n');
				ta.setSelectionEnd(ta.getText().length());
				tf.setText("");
			}
		});
	}
		private void connect() {
			ta.append("尝试连接\n");
			try {
				socket = new Socket("127.0.0.1",8998);
				writer = new PrintWriter(socket.getOutputStream(),true);
				ta.append("完成连接\n");
			}catch(Exception e) {
				e.printStackTrace();
			}
		}
		public static void main(String[] args) {
			MyClien clien = new MyClien("向服务器传送数据");
			clien.setSize(200,200);
			clien.setVisible(true);
			clien.connect();
		}
	}

Server-side operation result:

The server socket has been created successfully
Waiting for the client Connect
client: The revolution has not yet succeeded, comrades still need to work hard!

Client operation result:

Try to connect
Complete connection
The revolution has not yet succeeded, comrades still need to work hard!

Note:

When multiple network applications are installed on a machine, it is possible that the specified port number has been occupied. You may also encounter a situation where a network program that previously ran well suddenly fails to run. This situation may also be due to the port being occupied by another program. At this time, use the command netstat -an to view the ports used by the program.

                There is another very important point here. The two source codes mentioned in this article are one is the server-side program and the other is the client-side program. When running, the server program must be run first, and then the client program, and the port numbers of the two pieces of code must be the same.

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