java实现TCP socket和UDP socket的实例

Java实现TCP Socket和UDP Socket是网络编程中非常常见的任务。在此，我将向你介绍Java实现TCP和UDP Socket的完整攻略。

TCP Socket

步骤

Java实现TCP Socket的步骤如下：

1.创建一个ServerSocket对象，绑定IP地址和端口号

ServerSocket serverSocket = new ServerSocket(port, backlog, InetAddress.getByName(ip));

2.调用accept()方法监听客户端请求，并返回一个新的Socket对象

Socket socket = serverSocket.accept();

3.根据Socket对象获取输入输出流进行通信

BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
PrintWriter writer = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));

4.使用输入输出流进行通信（收发消息）

// 发送消息
writer.println("Hello, World!");
writer.flush();

// 接收消息
String message = reader.readLine();

5.关闭Socket以及ServerSocket

socket.close();
serverSocket.close();

示例说明

下面提供一个简单的示例，实现一个TCP Socket客户端和服务器端的简单通信（以字符串形式发送和接收消息）：

服务器端

public class TCPServer {
    public static void main(String[] args) throws IOException {
        ServerSocket serverSocket = new ServerSocket(8888, 50, InetAddress.getByName("127.0.0.1"));
        System.out.println("Server started!");

        Socket socket = serverSocket.accept();
        System.out.println("Client connected: " + socket.getInetAddress().getHostAddress());

        BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        PrintWriter writer = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));

        String message = "";
        while (!message.equals("exit")) {
            message = reader.readLine();
            System.out.println("Received message: " + message);
            writer.println("Echo: " + message);
            writer.flush();
        }

        socket.close();
        serverSocket.close();
    }
}

客户端

public class TCPClient {
    public static void main(String[] args) throws IOException {
        Socket socket = new Socket("127.0.0.1", 8888);
        System.out.println("Connected to server!");

        BufferedReader reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
        PrintWriter writer = new PrintWriter(new OutputStreamWriter(socket.getOutputStream()));

        String message = "";
        Scanner sc = new Scanner(System.in);
        while (!message.equals("exit")) {
            System.out.print("Enter message: ");
            message = sc.nextLine();
            writer.println(message);
            writer.flush();

            String reply = reader.readLine();
            System.out.println("Received reply: " + reply);
        }

        socket.close();
    }
}

UDP Socket

步骤

Java实现UDP Socket的步骤如下：

1.创建一个DatagramSocket对象（可以指定本地端口）

DatagramSocket socket = new DatagramSocket(port);

2.发送数据报文（数据+目标地址）

byte[] buf = "Hello, World!".getBytes();
DatagramPacket packet = new DatagramPacket(buf, buf.length, InetAddress.getByName(ip), port);
socket.send(packet);

3.接收数据报文

byte[] buf = new byte[1024];
DatagramPacket packet = new DatagramPacket(buf, buf.length);
socket.receive(packet);

4.关闭DatagramSocket

socket.close();

示例说明

下面提供一个简单的示例，实现一个UDP Socket客户端和服务器端的简单通信（以字符串形式发送和接收消息）：

服务器端

public class UDPServer {
    public static void main(String[] args) throws IOException {
        DatagramSocket socket = new DatagramSocket(8888);
        System.out.println("Server started!");

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

        while (true) {
            socket.receive(packet);
            String message = new String(buf, 0, packet.getLength());
            System.out.println("Received message: " + message);

            // echo back
            byte[] replyBuf = ("Echo: " + message).getBytes();
            DatagramPacket replyPacket = new DatagramPacket(replyBuf, replyBuf.length, packet.getAddress(), packet.getPort());
            socket.send(replyPacket);
        }

        // socket.close();
    }
}

客户端

public class UDPClient {
    public static void main(String[] args) throws IOException {
        DatagramSocket socket = new DatagramSocket();
        System.out.println("Connected to server!");
        String message = "";

        Scanner sc = new Scanner(System.in);
        while (!message.equals("exit")) {
            System.out.print("Enter message: ");
            message = sc.nextLine();

            byte[] buf = message.getBytes();
            DatagramPacket packet = new DatagramPacket(buf, buf.length, InetAddress.getByName("127.0.0.1"), 8888);
            socket.send(packet);

            byte[] replyBuf = new byte[1024];
            DatagramPacket replyPacket = new DatagramPacket(replyBuf, replyBuf.length);
            socket.receive(replyPacket);
            String reply = new String(replyBuf, 0, replyPacket.getLength());
            System.out.println("Received reply: " + reply);
        }

        socket.close();
    }
}

以上就是Java实现TCP Socket和UDP Socket的完整攻略以及两个示例。

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