Java网络编程练习题详解:从基础通信到远程控制的实战代码

1. 使用Socket实现客户端和服务器端的简单通信

实现思路

  • 服务器端:使用ServerSocket监听指定端口,等待客户端连接。一旦有客户端连接,通过Socket的输入输出流与客户端进行通信。
  • 客户端:通过Socket连接到服务器的指定端口,发送消息并接收服务器的响应。

代码实现

服务器端代码

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

public class SimpleServer {
    public static void main(String[] args) {
        int port = 12345; // 服务器监听端口
        try (ServerSocket serverSocket = new ServerSocket(port)) {
            System.out.println("服务器已启动,等待客户端连接...");
            Socket clientSocket = serverSocket.accept(); // 等待客户端连接
            System.out.println("客户端已连接");

            // 获取输入输出流
            BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
            PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);

            // 接收客户端消息并响应
            String clientMessage;
            while ((clientMessage = in.readLine()) != null) {
                System.out.println("客户端消息: " + clientMessage);
                out.println("服务器已收到消息: " + clientMessage);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

客户端代码

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

public class SimpleClient {
    public static void main(String[] args) {
        String host = "localhost";
        int port = 12345; // 服务器端口
        try (Socket socket = new Socket(host, port)) {
            System.out.println("已连接到服务器");

            // 获取输入输出流
            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);

            // 向服务器发送消息
            out.println("你好,服务器!");
            String serverResponse = in.readLine();
            System.out.println("服务器响应: " + serverResponse);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

说明

  • 服务器端使用ServerSocket监听端口,通过accept()方法等待客户端连接。
  • 客户端通过Socket连接到服务器的指定端口。
  • 双方通过输入输出流进行通信。

2. 使用ServerSocket监听端口并接受客户端连接

实现思路

  • 创建一个ServerSocket对象,绑定到一个端口。
  • 使用accept()方法等待客户端连接。
  • 每次有客户端连接时,打印客户端的IP地址和端口号。

代码实现

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

public class ServerSocketExample {
    public static void main(String[] args) {
        int port = 8080; // 监听端口
        try (ServerSocket serverSocket = new ServerSocket(port)) {
            System.out.println("服务器已启动,监听端口: " + port);
            while (true) {
                Socket clientSocket = serverSocket.accept(); // 等待客户端连接
                System.out.println("客户端已连接: " + clientSocket.getInetAddress().getHostAddress() + ":" + clientSocket.getPort());
                clientSocket.close(); // 关闭连接
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

说明

  • ServerSocketaccept()方法会阻塞,直到有客户端连接。
  • 每次有客户端连接时,会打印客户端的IP地址和端口号。

3. 实现一个简单的文件传输客户端和服务器

实现思路

  • 服务器端:接收客户端连接,接收文件内容并保存到本地。
  • 客户端:连接到服务器,发送文件内容。

代码实现

服务器端代码

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

public class FileTransferServer {
    public static void main(String[] args) {
        int port = 12345; // 服务器监听端口
        try (ServerSocket serverSocket = new ServerSocket(port)) {
            System.out.println("文件传输服务器已启动,等待客户端连接...");
            Socket clientSocket = serverSocket.accept(); // 等待客户端连接
            System.out.println("客户端已连接");

            // 接收文件
            InputStream in = clientSocket.getInputStream();
            FileOutputStream fos = new FileOutputStream("received_file.txt");
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = in.read(buffer)) != -1) {
                fos.write(buffer, 0, bytesRead);
            }
            fos.close();
            System.out.println("文件接收完成");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

客户端代码

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

public class FileTransferClient {
    public static void main(String[] args) {
        String host = "localhost";
        int port = 12345; // 服务器端口
        try (Socket socket = new Socket(host, port)) {
            System.out.println("已连接到文件传输服务器");

            // 发送文件
            File file = new File("file_to_send.txt");
            FileInputStream fis = new FileInputStream(file);
            OutputStream out = socket.getOutputStream();
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = fis.read(buffer)) != -1) {
                out.write(buffer, 0, bytesRead);
            }
            fis.close();
            System.out.println("文件发送完成");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

说明

  • 客户端通过FileInputStream读取文件内容,通过Socket的输出流发送到服务器。
  • 服务器通过Socket的输入流接收文件内容,保存到本地文件中。

4. 使用DatagramSocket实现UDP通信

实现思路

  • 发送端:创建DatagramSocket,通过DatagramPacket发送数据。
  • 接收端:创建DatagramSocket,通过DatagramPacket接收数据。

代码实现

发送端代码

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

public class UDPSender {
    public static void main(String[] args) {
        String host = "localhost";
        int port = 12345; // 接收端端口
        try (DatagramSocket socket = new DatagramSocket()) {
            String message = "Hello, UDP!";
            byte[] buffer = message.getBytes();
            InetAddress address = InetAddress.getByName(host);
            DatagramPacket packet = new DatagramPacket(buffer, buffer.length, address, port);
            socket.send(packet);
            System.out.println("消息已发送");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

接收端代码

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

public class UDPReceiver {
    public static void main(String[] args) {
        int port = 12345; // 监听端口
        try (DatagramSocket socket = new DatagramSocket(port)) {
            System.out.println("UDP接收端已启动,监听端口: " + port);
            byte[] buffer = new byte[1024];
            DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
            socket.receive(packet);
            String message = new String(packet.getData(), 0, packet.getLength());
            System.out.println("接收到消息: " + message);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

说明

  • UDP通信是无连接的,发送端和接收端不需要建立连接。
  • 数据通过DatagramPacket封装和传输。

5. 实现一个简单的聊天室服务器和客户端

实现思路

  • 服务器端:使用ServerSocket监听端口,接受多个客户端连接。为每个客户端创建一个线程,接收客户端消息并广播给所有其他客户端。
  • 客户端:连接到服务器,发送消息并接收其他客户端的消息。

代码实现

服务器端代码

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

public class ChatServer {
    private static final int PORT = 12345;
    private static final List<ClientHandler> clientList = Collections.synchronizedList(new ArrayList<>());

    public static void main(String[] args) {
        try (ServerSocket serverSocket = new ServerSocket(PORT)) {
            System.out.println("聊天室服务器已启动,等待客户端连接...");
            while (true) {
                Socket clientSocket = serverSocket.accept();
                System.out.println("新客户端已连接: " + clientSocket.getInetAddress().getHostAddress());
                ClientHandler clientHandler = new ClientHandler(clientSocket);
                clientList.add(clientHandler);
                new Thread(clientHandler).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void broadcastMessage(String message) {
        for (ClientHandler client : clientList) {
            client.sendMessage(message);
        }
    }

    private static class ClientHandler implements Runnable {
        private final Socket clientSocket;
        private PrintWriter out;

        public ClientHandler(Socket socket) {
            this.clientSocket = socket;
        }

        @Override
        public void run() {
            try {
                BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
                out = new PrintWriter(clientSocket.getOutputStream(), true);

                String clientMessage;
                while ((clientMessage = in.readLine()) != null) {
                    System.out.println("客户端消息: " + clientMessage);
                    broadcastMessage(clientMessage);
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                out.close();
                try {
                    clientSocket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }

        public void sendMessage(String message) {
            out.println(message);
        }
    }
}

客户端代码

import java.io.*;
import java.net.*;
import java.util.Scanner;

public class ChatClient {
    private static final String SERVER_HOST = "localhost";
    private static final int SERVER_PORT = 12345;

    public static void main(String[] args) {
        try (Socket socket = new Socket(SERVER_HOST, SERVER_PORT)) {
            System.out.println("已连接到聊天室服务器");

            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
            Scanner scanner = new Scanner(System.in);

            new Thread(() -> {
                try {
                    String serverMessage;
                    while ((serverMessage = in.readLine()) != null) {
                        System.out.println("服务器消息: " + serverMessage);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }).start();

            while (true) {
                String message = scanner.nextLine();
                out.println(message);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

说明

  • 服务器端为每个客户端创建一个线程,接收客户端消息并广播给所有其他客户端。
  • 客户端通过Socket连接到服务器,发送消息并接收其他客户端的消息。

6. 使用HttpURLConnection发送HTTP请求

实现思路

  • 创建一个HttpURLConnection对象,设置请求方法(GET、POST等)。
  • 发送请求并接收响应。

代码实现

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

public class HttpExample {
    public static void main(String[] args) {
        String urlString = "https://api.example.com/data";
        try {
            URL url = new URL(urlString);
            HttpURLConnection connection = (HttpURLConnection) url.openConnection();
            connection.setRequestMethod("GET");

            int responseCode = connection.getResponseCode();
            System.out.println("响应码: " + responseCode);

            if (responseCode == HttpURLConnection.HTTP_OK) {
                BufferedReader in = new BufferedReader(new InputStreamReader(connection.getInputStream()));
                String inputLine;
                StringBuilder response = new StringBuilder();
                while ((inputLine = in.readLine()) != null) {
                    response.append(inputLine);
                }
                in.close();
                System.out.println("响应内容: " + response.toString());
            } else {
                System.out.println("请求失败");
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

说明

  • 使用HttpURLConnection发送HTTP请求,获取响应码和响应内容。

7. 实现一个简单的Web服务器

实现思路

  • 使用ServerSocket监听端口,接收HTTP请求。
  • 解析请求,返回简单的HTML页面。

代码实现

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

public class SimpleWebServer {
    private static final int PORT = 8080;

    public static void main(String[] args) {
        try (ServerSocket serverSocket = new ServerSocket(PORT)) {
            System.out.println("Web服务器已启动,监听端口: " + PORT);
            while (true) {
                Socket clientSocket = serverSocket.accept();
                new Thread(() -> handleRequest(clientSocket)).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static void handleRequest(Socket clientSocket) {
        try (BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
             PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true)) {
            String requestLine = in.readLine();
            System.out.println("请求: " + requestLine);

            // 返回简单的HTML页面
            out.println("HTTP/1.1 200 OK");
            out.println("Content-Type: text/html");
            out.println();
            out.println("<html><body><h1>Hello, Web!</h1></body></html>");
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                clientSocket.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
}

说明

  • Web服务器通过ServerSocket监听端口,接收HTTP请求。
  • 返回简单的HTML页面作为响应。

8. 使用Socket实现多线程服务器

实现思路

  • 使用ServerSocket监听端口,接受客户端连接。
  • 为每个客户端创建一个线程,处理客户端请求。

代码实现

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

public class MultiThreadedServer {
    private static final int PORT = 12345;

    public static void main(String[] args) {
        try (ServerSocket serverSocket = new ServerSocket(PORT)) {
            System.out.println("多线程服务器已启动,监听端口: " + PORT);
            while (true) {
                Socket clientSocket = serverSocket.accept();
                System.out.println("新客户端已连接: " + clientSocket.getInetAddress().getHostAddress());
                new Thread(new ClientHandler(clientSocket)).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static class ClientHandler implements Runnable {
        private final Socket clientSocket;

        public ClientHandler(Socket socket) {
            this.clientSocket = socket;
        }

        @Override
        public void run() {
            try (BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
                 PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true)) {
                String clientMessage;
                while ((clientMessage = in.readLine()) != null) {
                    System.out.println("客户端消息: " + clientMessage);
                    out.println("服务器已收到消息: " + clientMessage);
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    clientSocket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

说明

  • 服务器为每个客户端创建一个线程,处理客户端请求。

9. 实现一个简单的文件下载客户端

实现思路

  • 使用Socket连接到服务器,请求下载文件。
  • 接收文件内容并保存到本地。

代码实现

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

public class FileDownloadClient {
    private static final String SERVER_HOST = "localhost";
    private static final int SERVER_PORT = 12345;

    public static void main(String[] args) {
        try (Socket socket = new Socket(SERVER_HOST, SERVER_PORT)) {
            System.out.println("已连接到文件下载服务器");

            // 接收文件
            InputStream in = socket.getInputStream();
            FileOutputStream fos = new FileOutputStream("downloaded_file.txt");
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = in.read(buffer)) != -1) {
                fos.write(buffer, 0, bytesRead);
            }
            fos.close();
            System.out.println("文件下载完成");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

说明

  • 客户端通过Socket连接到服务器,接收文件内容并保存到本地。

10. 使用Socket实现一个简单的远程控制服务器

实现思路

  • 服务器端:接收客户端连接,接收客户端发送的命令并执行。
  • 客户端:连接到服务器,发送命令。

代码实现

服务器端代码

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

public class RemoteControlServer {
    private static final int PORT = 12345;

    public static void main(String[] args) {
        try (ServerSocket serverSocket = new ServerSocket(PORT)) {
            System.out.println("远程控制服务器已启动,监听端口: " + PORT);
            while (true) {
                Socket clientSocket = serverSocket.accept();
                System.out.println("新客户端已连接: " + clientSocket.getInetAddress().getHostAddress());
                new Thread(new ClientHandler(clientSocket)).start();
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    private static class ClientHandler implements Runnable {
        private final Socket clientSocket;

        public ClientHandler(Socket socket) {
            this.clientSocket = socket;
        }

        @Override
        public void run() {
            try (BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
                 PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true)) {
                String clientCommand;
                while ((clientCommand = in.readLine()) != null) {
                    System.out.println("客户端命令: " + clientCommand);
                    Process process = Runtime.getRuntime().exec(clientCommand);
                    BufferedReader processOutput = new BufferedReader(new InputStreamReader(process.getInputStream()));
                    String line;
                    while ((line = processOutput.readLine()) != null) {
                        out.println(line);
                    }
                }
            } catch (IOException e) {
                e.printStackTrace();
            } finally {
                try {
                    clientSocket.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }
}

客户端代码

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

public class RemoteControlClient {
    private static final String SERVER_HOST = "localhost";
    private static final int SERVER_PORT = 12345;

    public static void main(String[] args) {
        try (Socket socket = new Socket(SERVER_HOST, SERVER_PORT)) {
            System.out.println("已连接到远程控制服务器");

            BufferedReader in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
            Scanner scanner = new Scanner(System.in);

            new Thread(() -> {
                try {
                    String serverResponse;
                    while ((serverResponse = in.readLine()) != null) {
                        System.out.println("服务器响应: " + serverResponse);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }).start();

            while (true) {
                System.out.print("请输入命令: ");
                String command = scanner.nextLine();
                out.println(command);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

说明

  • 服务器端接收客户端发送的命令,通过Runtime.exec()执行命令,并将输出发送回客户端。
  • 客户端发送命令并接收服务器的响应。
posted @ 2025-04-06 09:49  软件职业规划  阅读(21)  评论(0)    收藏  举报
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