Java Socket套接字如何實現數據傳輸

在Java中，使用Socket套接字進行數據傳輸主要涉及到兩個類：java.net.Socket（用于客戶端）和java.net.ServerSocket（用于服務器端）。以下是使用這兩個類實現數據傳輸的基本步驟：

服務器端

1. 創建ServerSocket對象：

   ServerSocket serverSocket = new ServerSocket(port);
   

   其中port是服務器監聽的端口號。

2. 接受客戶端連接：

   Socket clientSocket = serverSocket.accept();
   

   這行代碼會阻塞，直到有客戶端連接到服務器。

3. 獲取輸入輸出流：

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

4. 讀取和寫入數據：

   // 讀取客戶端發送的數據
   BufferedReader reader = new BufferedReader(new InputStreamReader(input));
   String receivedData = reader.readLine();
   
   // 向客戶端發送數據
   PrintWriter writer = new PrintWriter(output, true);
   writer.println("Hello, Client!");
   

5. 關閉資源：

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

客戶端

1. 創建Socket對象：

   Socket socket = new Socket(serverAddress, port);
   

   其中serverAddress是服務器的IP地址或主機名，port是服務器監聽的端口號。

2. 獲取輸入輸出流：

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

3. 讀取和寫入數據：

   // 向服務器發送數據
   PrintWriter writer = new PrintWriter(output, true);
   writer.println("Hello, Server!");
   
   // 讀取服務器發送的數據
   BufferedReader reader = new BufferedReader(new InputStreamReader(input));
   String receivedData = reader.readLine();
   System.out.println(receivedData);
   

4. 關閉資源：

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

示例代碼

服務器端代碼

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();
        }
    }
}

客戶端代碼

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();
        }
    }
}

通過上述步驟和示例代碼，你可以在Java中使用Socket套接字實現基本的數據傳輸。