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socket如何使用java

2026-03-25 16:08:36Java

使用Java创建Socket通信

Java提供了java.net.Socket和java.net.ServerSocket类来实现TCP协议的网络通信。以下分客户端和服务端两部分说明。

服务端实现

创建ServerSocket监听指定端口，等待客户端连接：

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

public class Server {
    public static void main(String[] args) throws IOException {
        int port = 8080;
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("服务端启动，监听端口：" + port);

        Socket clientSocket = serverSocket.accept();
        System.out.println("客户端连接：" + 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("收到客户端消息：" + inputLine);
            out.println("服务端回复：" + inputLine);
        }
    }
}

客户端实现

创建Socket连接到服务端，进行数据交换：

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

public class Client {
    public static void main(String[] args) throws IOException {
        String host = "localhost";
        int port = 8080;

        Socket socket = new Socket(host, port);
        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("收到服务端回复：" + in.readLine());
        }
    }
}

UDP通信实现

对于UDP协议，使用DatagramSocket和DatagramPacket：

服务端实现

import java.net.*;

public class UDPServer {
    public static void main(String[] args) throws Exception {
        DatagramSocket socket = new DatagramSocket(9876);
        byte[] buffer = new byte[1024];

        while (true) {
            DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
            socket.receive(packet);
            String received = new String(packet.getData(), 0, packet.getLength());
            System.out.println("收到UDP消息：" + received);
        }
    }
}

客户端实现

import java.net.*;

public class UDPClient {
    public static void main(String[] args) throws Exception {
        DatagramSocket socket = new DatagramSocket();
        byte[] buf = "Hello UDP".getBytes();

        InetAddress address = InetAddress.getByName("localhost");
        DatagramPacket packet = new DatagramPacket(
            buf, buf.length, address, 9876);
        socket.send(packet);
    }
}

异常处理与资源释放

网络通信需要处理IOException并确保资源正确释放：

try (Socket socket = new Socket(host, port);
     OutputStream out = socket.getOutputStream();
     InputStream in = socket.getInputStream()) {
    // 通信逻辑
} catch (IOException e) {
    e.printStackTrace();
}

多线程处理多客户端

服务端通常需要多线程处理并发连接：

socket如何使用java

while (true) {
    Socket clientSocket = serverSocket.accept();
    new Thread(() -> {
        try {
            // 处理客户端请求
        } catch (IOException e) {
            e.printStackTrace();
        }
    }).start();
}