java 写一个 AES 方法

AES（Advanced Encryption Standard），即高级加密标准，是一种常用的对称加密算法。在Java中，我们可以利用`javax.crypto.Cipher`类来实现AES加密。以下是一个简单的AES加密示例，使用了CBC模式（Cipher Block Chaining）：

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.security.SecureRandom;

public class AESEncryption {
    private static final String ALGORITHM = "AES";
    private static final byte[] keyValue = "your_secret_key_128_chars".getBytes(); // 16 bytes for 128-bit key
    private static final SecureRandom random = new SecureRandom();

    public static String encrypt(String data) throws Exception {
        IvParameterSpec iv = new IvParameterSpec(keyValue);
        SecretKeySpec secretKey = new SecretKeySpec(keyValue, ALGORITHM);

        Cipher cipher = Cipher.getInstance(ALGORITHM + "/CBC/PKCS5Padding");
        cipher.init(Cipher.ENCRYPT_MODE, secretKey, iv);

        byte[] encryptedData = cipher.doFinal(data.getBytes());
        return Base64.getEncoder().encodeToString(encryptedData); // 返回Base64编码以便存储或传输
    }

    public static String decrypt(String encryptedData) throws Exception {
        byte[] encodedData = Base64.getDecoder().decode(encryptedData);
        // 同样的IV用于解密
        IvParameterSpec iv = new IvParameterSpec(keyValue);
        SecretKeySpec secretKey = new SecretKeySpec(keyValue, ALGORITHM);

        Cipher cipher = Cipher.getInstance(ALGORITHM + "/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, secretKey, iv);

        byte[] decryptedData = cipher.doFinal(encodedData);
        return new String(decryptedData);
    }
}

在这个例子中，你需要替换`"your_secret_key_128_chars"`为你实际使用的AES密钥。