How does Java network programming communicate between the server and the client?

In Java network programming, the server and client communicate through the client-server model. Follow the following steps: Create the server: Use ServerSocket to listen on the port and wait for the client to connect. Handle the client request: accept the connection and read data from the client, process the request and return the response, and finally close the client socket. Create a client: establish a Socket connection, send a request to the server, read the response and close the socket.

Java network programming: server-side and client communication

In Java network programming, between the server and the client The communication follows the client-server model. This article will delve into how the server side and client side establish a connection and exchange data through sockets.

Create the server side

The server side is responsible for listening to client connections and processing requests from clients. In order to create a server side, you can use the following steps:

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

public class Server {

    public static void main(String[] args) throws IOException {
        // 创建一个服务器套接字，监听端口 8080
        ServerSocket serverSocket = new ServerSocket(8080);

        // 循环等待客户端连接
        while (true) {
            // 接受客户端连接并返回一个套接字
            Socket clientSocket = serverSocket.accept();

            // 处理客户端请求
            handleClientRequest(clientSocket);

            // 关闭客户端套接字
            clientSocket.close();
        }

        // 关闭服务器套接字
        serverSocket.close();
    }

    public static void handleClientRequest(Socket clientSocket) throws IOException {
        // 从输入流读取客户端数据
        InputStream inputStream = clientSocket.getInputStream();
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
        String request = reader.readLine();

        // 处理请求并返回响应
        String response = processRequest(request);

        // 向输出流写入响应
        OutputStream outputStream = clientSocket.getOutputStream();
        PrintWriter writer = new PrintWriter(outputStream);
        writer.println(response);
    }
}

Create Client

The client is responsible for connecting to the server side and sending requests. The following steps are used to create a client:

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

public class Client {

    public static void main(String[] args) throws IOException {
        // 创建一个客户端套接字并连接到服务器端（主机名：localhost，端口：8080）
        Socket clientSocket = new Socket("localhost", 8080);

        // 向服务器端发送请求
        OutputStream outputStream = clientSocket.getOutputStream();
        PrintWriter writer = new PrintWriter(outputStream);
        writer.println("Hello from client!");

        // 从服务器端读取响应
        InputStream inputStream = clientSocket.getInputStream();
        BufferedReader reader = new BufferedReader(new InputStreamReader(inputStream));
        String response = reader.readLine();
        System.out.println("Response from server: " + response);

        // 关闭客户端套接字
        clientSocket.close();
    }
}

Practical case

The following is a practical case that demonstrates how to use Java network programming between the server and the client Communicate between:

Server-side code:

// Server.java
import java.net.*;
import java.io.*;

public class Server {

    public static void main(String[] args) throws IOException {
        // 监听端口 8080
        ServerSocket serverSocket = new ServerSocket(8080);

        // 等待客户端连接
        Socket clientSocket = serverSocket.accept();

        // 读取客户端数据
        BufferedReader reader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        String request = reader.readLine();
        System.out.println("Received request: " + request);

        // 响应客户端请求
        PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
        writer.println("Hello from server!");
        writer.flush();

        // 关闭套接字
        clientSocket.close();
        serverSocket.close();
    }
}

Client-side code:

// Client.java
import java.net.*;
import java.io.*;

public class Client {

    public static void main(String[] args) throws IOException {
        // 连接到服务器端（主机名：localhost，端口：8080）
        Socket clientSocket = new Socket("localhost", 8080);

        // 向服务器端发送数据
        PrintWriter writer = new PrintWriter(clientSocket.getOutputStream());
        writer.println("Hello from client!");
        writer.flush();

        // 读取服务器端响应
        BufferedReader reader = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        String response = reader.readLine();
        System.out.println("Received response: " + response);

        // 关闭套接字
        clientSocket.close();
    }
}

After running this code, the server The client will listen for connections on port 8080, and the client will connect to the server and send a "Hello from client!" message. The server will receive the message and respond with "Hello from server!".

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