Methods of using Socket to communicate multi-threaded and long connections in Java Web projects

Many times in javaweb projects, we need to use Socket communication to implement functions. When using Socket in the web, we need to establish a listener program, and start socket listening when the program starts. Our application scenario is in a Java project, which requires external hardware devices to communicate through tcp to obtain data uploaded by the device and respond to the data.

Let's take a look at the web listening code:

 import javax.servlet.ServletContextEvent;import javax.servlet.ServletContextListener;public class AttendSocetListener implements ServletContextListener{private SocketThread socketThread;public void contextDestroyed(ServletContextEvent arg) { if(null!=socketThread && !socketThread.isInterrupt()) { socketThread.closeSocketServer(); socketThread.interrupt(); } } @Override public void contextInitialized(ServletContextEvent arg) { // TODO Auto-generated method stub if(null==socketThread) { // Create new thread class socketThread=new SocketThread(null); // Start thread socketThread.start(); } } }

Create thread:

 import java.io.IOException;import java.net.ServerSocket;import java.net.Socket;import java.util.ArrayList;import java.util.List;public class SocketThread extends Thread{private ServerSocket serverSocket = null; public SocketThread(ServerSocket serverScoket){ try { if(null == serverSocket){ this.serverSocket = new ServerSocket(); System.out.println("socket start"); } } catch (Exception e) { System.out.println("SocketThread error creating socket service"); e.printStackTrace(); } } public void run(){ while(true){ try { if(serverSocket==null){break;}else if(serverSocket.isClosed()){break;}Socket socket = serverSocket.accept(); if(null != socket && !socket.isClosed()){ // Process accepted data Thread t = new Thread(new SocketOperate(socket)); t.start(); }else{break;}}catch (Exception e) { System.out.println("Error creating socket service in SocketThread"); e.printStackTrace(); } } } public void closeSocketServer(){ try { if(null!=serverSocket && !serverSocket.isClosed()) { serverSocket.close(); } } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }

Processing received data:

 import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStream;import java.net.Socket;public class SocketOperate implements Runnable { private Socket socket; //Input stream corresponding to Socket processed by this thread BufferedReader br = null; String str = null; String content = null; InputStreamReader reader=null; public SocketOperate(Socket socket) throws IOException { this.socket = socket; reader = new InputStreamReader(this.socket.getInputStream(),"utf-"); br = new BufferedReader(reader); } @Override public void run() { try { // Use a loop to continuously read the data sent by the client from the Socket while (true) { content = readFromClient(); System.out.println(content); if (content == null) { break; } OutputStream os = socket.getOutputStream(); os.write(("RES, OK,<Year Class, Xiao Ming>, ,#" + "/n").getBytes("utf-")); os.flush();} } catch (IOException e) { e.printStackTrace(); } } //Define the method to read client data private String readFromClient() { try { str = br.readLine(); return str; } //If an exception is caught, it means that the client corresponding to the socket has closed the catch (IOException e) { try {br.close();reader.close();socket.close();} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();} } return null; } }

Client code:

 packageimport java.io.*;import java.net.*;public class TalkClient {public static void main(String args[]) throws UnknownHostException, IOException {Socket socket=new Socket("...",);PrintWriter os=new PrintWriter(socket.getOutputStream());BufferedReader is=new BufferedReader(new InputStreamReader(socket.getInputStream()));int i=;while(socket.isConnected()){os.print("BEAT,,,,.,#"+"/n");os.flush();System.out.println("Client:"+i);System.out.println("Server:"+is.readLine());i++;} //Continue looping os.close(); //Close Socket output stream is.close(); //Close Socket input stream socket.close(); //Close Socket}}

The above is the method of using Socket communication multi-threaded and long connections in Java Web projects introduced by the editor. I hope it will be helpful to everyone!