用RSA加密AES的密钥k,后用AES加密数据，Java实现

以下是用RSA加密AES密钥k，再用AES加密数据的Java代码示例：

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.SecureRandom;

public class Encryptor {

    public static void main(String[] args) throws Exception {
        // 生成AES密钥
        SecretKey aesKey = generateAESKey();

        // 生成RSA公私钥对
        KeyPair keyPair = generateRSAKeyPair();

        // 用RSA公钥加密AES密钥k
        byte[] encryptedKey = encryptRSA(aesKey.getEncoded(), keyPair.getPublic());

        // 用AES密钥k加密数据
        String plainText = "Hello, world!";
        byte[] encryptedData = encryptAES(plainText.getBytes(), aesKey);

        System.out.println("Encrypted key: " + bytesToHex(encryptedKey));
        System.out.println("Encrypted data: " + bytesToHex(encryptedData));

        // 用RSA私钥解密AES密钥k
        byte[] decryptedKey = decryptRSA(encryptedKey, keyPair.getPrivate());

        // 用AES密钥k解密数据
        byte[] decryptedData = decryptAES(encryptedData, decryptedKey);

        System.out.println("Decrypted data: " + new String(decryptedData));
    }

    // 生成AES密钥
    public static SecretKey generateAESKey() throws Exception {
        KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
        SecureRandom secureRandom = new SecureRandom();
        keyGenerator.init(128, secureRandom);
        return keyGenerator.generateKey();
    }

    // 生成RSA公私钥对
    public static KeyPair generateRSAKeyPair() throws Exception {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        SecureRandom secureRandom = new SecureRandom();
        keyPairGenerator.initialize(2048, secureRandom);
        return keyPairGenerator.generateKeyPair();
    }

    // 用RSA公钥加密数据
    public static byte[] encryptRSA(byte[] data, Key publicKey) throws Exception {
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        return cipher.doFinal(data);
    }

    // 用RSA私钥解密数据
    public static byte[] decryptRSA(byte[] encryptedData, Key privateKey) throws Exception {
        Cipher cipher = Cipher.getInstance("RSA");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        return cipher.doFinal(encryptedData);
    }

    // 用AES密钥加密数据
    public static byte[] encryptAES(byte[] data, SecretKey aesKey) throws Exception {
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.ENCRYPT_MODE, aesKey);
        return cipher.doFinal(data);
    }

    // 用AES密钥解密数据
    public static byte[] decryptAES(byte[] encryptedData, byte[] aesKeyBytes) throws Exception {
        SecretKey aesKey = new SecretKeySpec(aesKeyBytes, "AES");
        Cipher cipher = Cipher.getInstance("AES");
        cipher.init(Cipher.DECRYPT_MODE, aesKey);
        return cipher.doFinal(encryptedData);
    }

    // 将字节数组转为十六进制字符串
    public static String bytesToHex(byte[] bytes) {
        StringBuilder stringBuilder = new StringBuilder();
        for (byte b : bytes) {
            stringBuilder.append(String.format("%02X", b));
        }
        return stringBuilder.toString();
    }
}

注意，这里用AES-128加密数据，生成RSA-2048公私钥对，可以根据需要进行调整。此外，为了方便演示，这里使用了字符串类型的数据，实际上在实际应用中，可能需要将数据转为字节数组后再进行加密。