java 通过TCP\UDP 协议实现多人聊天，点对点，文件传送-----分服务器端和客户端 在此内容上添加发送消息有AES加密的代码详情

好的，您想了解关于Java通过TCP\UDP协议实现多人聊天、点对点、文件传送，并在此基础上添加发送消息有AES加密的代码详情，我可以为您提供一些基本的信息。

首先，TCP和UDP是两种不同的传输协议，分别对应于面向连接的可靠传输和面向无连接的不可靠传输。在使用这两种协议进行多人聊天、点对点、文件传送时，需要根据具体情况选择合适的协议。

下面以TCP协议为例，介绍如何实现多人聊天、点对点、文件传送，并在此基础上添加发送消息有AES加密的代码详情：

1. 服务器端

服务器端需要监听客户端的请求，建立连接，并处理接收到的消息。具体代码如下：

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

public class TCPServer {
    
    private static final String AES_ALGORITHM = "AES";
    private static final String CHARSET_NAME = "UTF-8";
    private static final int AES_KEY_SIZE = 128; // 128位密钥
    
    private SecretKey secretKey;
    
    public TCPServer() throws Exception {
        // 生成AES密钥
        KeyGenerator keyGen = KeyGenerator.getInstance(AES_ALGORITHM);
        keyGen.init(AES_KEY_SIZE);
        secretKey = keyGen.generateKey();
    }

    public void start(int port) throws IOException {
        ServerSocket serverSocket = new ServerSocket(port);
        System.out.println("Server started at port " + port);
        while (true) {
            Socket socket = serverSocket.accept();
            new Thread(() -> {
                try {
                    handleConnection(socket);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }).start();
        }
    }

    private void handleConnection(Socket socket) throws Exception {
        System.out.println("Client connected: " + socket.getRemoteSocketAddress());
        InputStream in = socket.getInputStream();
        OutputStream out = socket.getOutputStream();
        byte[] buffer = new byte[1024];
        int len;
        while ((len = in.read(buffer)) != -1) {
            String message = new String(buffer, 0, len, CHARSET_NAME);
            System.out.println("Received message from client: " + message);
            String decryptedMessage = decryptMessage(message);
            System.out.println("Decrypted message: " + decryptedMessage);
            String response = "Server response: " + decryptedMessage;
            String encryptedResponse = encryptMessage(response);
            out.write(encryptedResponse.getBytes(CHARSET_NAME));
            out.flush();
        }
        socket.close();
        System.out.println("Client disconnected: " + socket.getRemoteSocketAddress());
    }
    
    private String encryptMessage(String message) throws Exception {
        Cipher cipher = Cipher.getInstance(AES_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        byte[] encryptedData = cipher.doFinal(message.getBytes(CHARSET_NAME));
        return new String(encryptedData, CHARSET_NAME);
    }
    
    private String decryptMessage(String encryptedMessage) throws Exception {
        Cipher cipher = Cipher.getInstance(AES_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        byte[] decryptedData = cipher.doFinal(encryptedMessage.getBytes(CHARSET_NAME));
        return new String(decryptedData, CHARSET_NAME);
    }

    public static void main(String[] args) throws Exception {
        TCPServer server = new TCPServer();
        server.start(12345);
    }

}

在代码中，我们首先生成一个128位的AES密钥，并使用ServerSocket类监听客户端的请求。当有客户端连接时，我们开启一个新的线程来处理连接，并在该线程中读取客户端发送的消息，进行解密后给出响应。在解密和加密消息时，我们使用相同的AES密钥。

2. 客户端

客户端需要连接服务器，并发送消息。具体代码如下：

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.Socket;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;

public class TCPClient {
    
    private static final String AES_ALGORITHM = "AES";
    private static final String CHARSET_NAME = "UTF-8";
    private static final int AES_KEY_SIZE = 128; // 128位密钥
    
    private SecretKey secretKey;
    
    public TCPClient() throws Exception {
        // 生成AES密钥
        KeyGenerator keyGen = KeyGenerator.getInstance(AES_ALGORITHM);
        keyGen.init(AES_KEY_SIZE);
        secretKey = keyGen.generateKey();
    }

    public void connect(String host, int port) throws IOException {
        Socket socket = new Socket(host, port);
        System.out.println("Connected to server: " + socket.getRemoteSocketAddress());
        InputStream in = socket.getInputStream();
        OutputStream out = socket.getOutputStream();
        byte[] buffer = new byte[1024];
        while (true) {
            String message = "Hello, server!";
            String encryptedMessage = encryptMessage(message);
            out.write(encryptedMessage.getBytes(CHARSET_NAME));
            out.flush();
            int len = in.read(buffer);
            String response = new String(buffer, 0, len, CHARSET_NAME);
            String decryptedResponse = decryptMessage(response);
            System.out.println("Received response from server: " + decryptedResponse);
            Thread.sleep(1000);
        }
    }
    
    private String encryptMessage(String message) throws Exception {
        Cipher cipher = Cipher.getInstance(AES_ALGORITHM);
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        byte[] encryptedData = cipher.doFinal(message.getBytes(CHARSET_NAME));
        return new String(encryptedData, CHARSET_NAME);
    }
    
    private String decryptMessage(String encryptedMessage) throws Exception {
        Cipher cipher = Cipher.getInstance(AES_ALGORITHM);
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        byte[] decryptedData = cipher.doFinal(encryptedMessage.getBytes(CHARSET_NAME));
        return new String(decryptedData, CHARSET_NAME);
    }

    public static void main(String[] args) throws Exception {
        TCPClient client = new TCPClient();
        client.connect("localhost", 12345);
    }

}

在代码中，我们首先生成一个128位的AES密钥，并使用Socket类连接服务器。连接成功后，我们进入一个循环中，每隔一秒钟向服务器发送一条消息，并读取服务器的响应。在发送和接收消息时，我们使用相同的AES密钥。

以上代码只是简单示例，实际应用中还需要考虑一些细节问题，例如如何处理并发连接、如何发送和接收文件等等。同时，需要注意密钥的保密性，避免密钥被攻击者获取导致数据泄露。