Java Socket套接字如何实现数据传输

在Java中，使用Socket套接字进行数据传输主要涉及到两个类：java.net.Socket（用于客户端）和java.net.ServerSocket（用于服务器端）。以下是使用这两个类实现数据传输的基本步骤：

服务器端

1. 创建ServerSocket对象：

   ServerSocket serverSocket = new ServerSocket(port);
   

   其中port是服务器监听的端口号。

2. 接受客户端连接：

   Socket clientSocket = serverSocket.accept();
   

   这行代码会阻塞，直到有客户端连接到服务器。

3. 获取输入输出流：

   InputStream input = clientSocket.getInputStream();
   OutputStream output = clientSocket.getOutputStream();
   

4. 读取和写入数据：

   // 读取客户端发送的数据
   BufferedReader reader = new BufferedReader(new InputStreamReader(input));
   String receivedData = reader.readLine();
   
   // 向客户端发送数据
   PrintWriter writer = new PrintWriter(output, true);
   writer.println("Hello, Client!");
   

5. 关闭资源：

   reader.close();
   writer.close();
   clientSocket.close();
   serverSocket.close();
   

客户端

1. 创建Socket对象：

   Socket socket = new Socket(serverAddress, port);
   

   其中serverAddress是服务器的IP地址或主机名，port是服务器监听的端口号。

2. 获取输入输出流：

   InputStream input = socket.getInputStream();
   OutputStream output = socket.getOutputStream();
   

3. 读取和写入数据：

   // 向服务器发送数据
   PrintWriter writer = new PrintWriter(output, true);
   writer.println("Hello, Server!");
   
   // 读取服务器发送的数据
   BufferedReader reader = new BufferedReader(new InputStreamReader(input));
   String receivedData = reader.readLine();
   System.out.println(receivedData);
   

4. 关闭资源：

   reader.close();
   writer.close();
   socket.close();
   

示例代码

服务器端代码

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

public class Server {
    public static void main(String[] args) {
        int port = 12345;
        try (ServerSocket serverSocket = new ServerSocket(port)) {
            System.out.println("Server is listening on port " + port);

            while (true) {
                try (Socket clientSocket = serverSocket.accept()) {
                    System.out.println("New client connected");

                    InputStream input = clientSocket.getInputStream();
                    BufferedReader reader = new BufferedReader(new InputStreamReader(input));

                    OutputStream output = clientSocket.getOutputStream();
                    PrintWriter writer = new PrintWriter(output, true);

                    String receivedData = reader.readLine();
                    System.out.println("Received from client: " + receivedData);

                    writer.println("Hello, Client!");
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

客户端代码

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

public class Client {
    public static void main(String[] args) {
        String serverAddress = "localhost";
        int port = 12345;

        try (Socket socket = new Socket(serverAddress, port)) {
            OutputStream output = socket.getOutputStream();
            PrintWriter writer = new PrintWriter(output, true);

            writer.println("Hello, Server!");

            InputStream input = socket.getInputStream();
            BufferedReader reader = new BufferedReader(new InputStreamReader(input));

            String receivedData = reader.readLine();
            System.out.println("Received from server: " + receivedData);
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host " + serverAddress);
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

通过上述步骤和示例代码，你可以在Java中使用Socket套接字实现基本的数据传输。