java实现aes-128加密算法

Java中可以使用javax.crypto包来实现AES-128加密算法。下面是一个简单的示例代码：

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
import java.nio.charset.StandardCharsets;
import java.util.Base64;

public class AESUtil {
    private static final String ALGORITHM = "AES";
    private static final String TRANSFORMATION = "AES/ECB/PKCS5Padding";

    public static String encrypt(String plaintext, String key) throws Exception {
        SecretKeySpec secretKey = new SecretKeySpec(key.getBytes(StandardCharsets.UTF_8), ALGORITHM);
        Cipher cipher = Cipher.getInstance(TRANSFORMATION);
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);
        byte[] encryptedBytes = cipher.doFinal(plaintext.getBytes(StandardCharsets.UTF_8));
        return Base64.getEncoder().encodeToString(encryptedBytes);
    }

    public static String decrypt(String ciphertext, String key) throws Exception {
        SecretKeySpec secretKey = new SecretKeySpec(key.getBytes(StandardCharsets.UTF_8), ALGORITHM);
        Cipher cipher = Cipher.getInstance(TRANSFORMATION);
        cipher.init(Cipher.DECRYPT_MODE, secretKey);
        byte[] decryptedBytes = cipher.doFinal(Base64.getDecoder().decode(ciphertext));
        return new String(decryptedBytes, StandardCharsets.UTF_8);
    }
}

使用示例：

public class Main {
    public static void main(String[] args) {
        try {
            String plaintext = "Hello, World!";
            String key = "0123456789abcdef"; // 16字节的密钥

            String ciphertext = AESUtil.encrypt(plaintext, key);
            System.out.println("加密后的密文：" + ciphertext);

            String decryptedText = AESUtil.decrypt(ciphertext, key);
            System.out.println("解密后的明文：" + decryptedText);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

注意：在实际使用中，应该使用更安全的方式来存储密钥，例如使用密钥管理系统（Key Management System）来保护密钥的安全性。