如何利用Java API接口实现网络通信

要利用Java API接口实现网络通信，你可以使用Java提供的java.net包中的类和接口。以下是一个简单的示例，展示了如何使用Java API实现客户端和服务器之间的基本网络通信。

1. 创建一个简单的TCP服务器

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

public class SimpleTCPServer {
    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) {
                Socket socket = serverSocket.accept();
                System.out.println("New client connected");

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

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

                String message;
                while ((message = reader.readLine()) != null) {
                    System.out.println("Received from client: " + message);
                    writer.println("Server received: " + message);
                }

                socket.close();
            }
        } catch (IOException e) {
            System.out.println("Server exception: " + e.getMessage());
            e.printStackTrace();
        }
    }
}

2. 创建一个简单的TCP客户端

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

public class SimpleTCPClient {
    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);

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

            // Send a message to the server
            writer.println("Hello, Server!");

            // Receive a response from the server
            String message = reader.readLine();
            System.out.println("Received from server: " + message);
        } catch (UnknownHostException e) {
            System.out.println("Server not found: " + e.getMessage());
        } catch (IOException e) {
            System.out.println("I/O error: " + e.getMessage());
        }
    }
}

首先运行服务器端代码，然后运行客户端代码。客户端将向服务器发送一条消息，服务器接收并回复客户端。这个示例展示了如何使用Java API进行基本的网络通信。你可以根据需要扩展这个示例，例如添加多线程以支持多个客户端，或者实现更复杂的协议。