Java网络编程：客户端服务器通信问题实例

原创た入场券 2024-09-25 02:42 95阅读 0赞

在Java网络编程中，客户端与服务器之间的通信通常涉及到Socket、ServerSocket、TCP/IP等协议。以下是一个简单的实例，演示了客户端向服务器发送消息的过程：

1. **创建服务器端**（Server Side）

```java
import java.io.*;
import java.net.ServerSocket;
import java.net.Socket;

public class Server {
    public static void main(String[] args) throws IOException {
        // 设置监听的端口
        int port = 9999;
        
        // 创建ServerSocket
        ServerSocket serverSocket = new ServerSocket(port);
        
        System.out.println("Server is listening on port " + port);

// 等待客户端连接
        Socket socket = serverSocket.accept();
        
        System.out.println("New connection from: " + socket.getRemoteSocketAddress()));

// 读取客户端发送的数据
        BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream())));

String messageFromClient = in.readLine(); // 获取消息

System.out.println("Message received from client: " + messageFromClient));

// 向客户端发送消息
        BufferedWriter out = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()))));
        out.write("Server replied to client: " + messageFromClient); // 发送消息
        out.flush();
    }
}
```

2. **创建客户端**（Client Side）

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

public class Client {
    public static void main(String[] args) throws IOException {
        // 客户端连接到服务器的IP和端口
        String serverAddress = "localhost"; // 更改为你的服务器实际IP
        int serverPort = 9999; // 保持为服务器端设置的端口

System.out.println("Connecting to Server on IP: " + serverAddress + " and Port: " + serverPort);

try (Socket socket = new Socket(serverAddress, serverPort)))) {
            // 操作连接成功的Socket
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()))));
            BufferedWriter out = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()))));

System.out.println("Connection Established. Sending message...");

// 发送消息
            String clientMessage = "Hello from Client!"; // 更改为你要发送的实际信息
            out.write(clientMessage); // 发送数据
            out.flush();

System.out.println("Client Message sent. Receiving server response...");

// 读取服务器响应
            String serverResponse = in.readLine(); // 获取消息
            System.out.println("Server Response: " + serverResponse);

} catch (SocketException e) {
            System.err.println("Error Connecting to Server: " + e.getMessage());
        } catch (IOException i) {
            System.err.println("Error Sending Message or Receiving Response: " + i.getMessage());
        }
    }
}
```

3. **运行客户端和服务器**（双端运行）

分别在你的开发环境中运行这两个程序。当客户端发送消息后，你会看到服务器的响应。