linux下java socket通信

基础概念

Linux下的Java Socket通信是指在Linux操作系统环境下，使用Java编程语言实现的网络通信。Socket（套接字）是网络通信的基本构建块，它允许不同计算机之间通过网络进行数据交换。Java提供了java.net包来处理Socket通信，包括TCP（传输控制协议）和UDP（用户数据报协议）两种类型。

优势

跨平台性：Java语言本身是跨平台的，因此基于Java的Socket通信可以在不同的操作系统上运行。
丰富的API：Java提供了丰富的java.net包API，使得网络编程变得简单和高效。
安全性：Java的Socket通信支持SSL/TLS加密，可以保证数据传输的安全性。
可扩展性：Java的Socket通信可以很容易地扩展到大规模的网络应用中。

类型

TCP Socket：基于TCP协议，提供可靠的、面向连接的通信服务。数据传输是有序的，且不会丢失。
UDP Socket：基于UDP协议，提供无连接的通信服务。数据传输速度快，但不保证数据的有序性和可靠性。

应用场景

客户端-服务器应用：例如Web服务器、FTP服务器、聊天应用等。
分布式系统：例如分布式计算、数据同步等。
实时通信：例如视频会议、在线游戏等。

示例代码

TCP Socket通信

服务器端代码

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

public class TCPServer {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(8080);
        System.out.println("Server started, listening on port 8080...");

        Socket clientSocket = serverSocket.accept();
        System.out.println("Client connected from " + clientSocket.getInetAddress());

        BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);

        String inputLine;
        while ((inputLine = in.readLine()) != null) {
            System.out.println("Received from client: " + inputLine);
            out.println("Echo: " + inputLine);
        }

        clientSocket.close();
        serverSocket.close();
    }
}

客户端代码

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

public class TCPClient {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("localhost", 8080);
        System.out.println("Connected to server");

        PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));

        String userInput;
        while ((userInput = stdIn.readLine()) != null) {
            out.println(userInput);
            System.out.println("Server response: " + in.readLine());
        }

        socket.close();
    }
}

UDP Socket通信

服务器端代码

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

public class UDPServer {
    public static void main(String[] args) throws IOException {
        DatagramSocket socket = new DatagramSocket(8080);
        System.out.println("Server started, listening on port 8080...");

        byte[] buffer = new byte[1024];
        DatagramPacket packet = new DatagramPacket(buffer, buffer.length);

        while (true) {
            socket.receive(packet);
            String received = new String(packet.getData(), 0, packet.getLength());
            System.out.println("Received from client: " + received);

            byte[] sendData = ("Echo: " + received).getBytes();
            DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, packet.getAddress(), packet.getPort());
            socket.send(sendPacket);
        }
    }
}

客户端代码

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

public class UDPClient {
    public static void main(String[] args) throws IOException {
        DatagramSocket socket = new DatagramSocket();
        InetAddress address = InetAddress.getByName("localhost");
        int port = 8080;

        BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
        String userInput;

        while ((userInput = stdIn.readLine()) != null) {
            byte[] sendData = userInput.getBytes();
            DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, address, port);
            socket.send(sendPacket);

            byte[] buffer = new byte[1024];
            DatagramPacket receivePacket = new DatagramPacket(buffer, buffer.length);
            socket.receive(receivePacket);
            String received = new String(receivePacket.getData(), 0, receivePacket.getLength());
            System.out.println("Server response: " + received);
        }

        socket.close();
    }
}