JAVA实现AES加解密代码简化版

以下是JAVA实现AES加解密的简化版代码：

import javax.crypto.Cipher;
import javax.crypto.spec.SecretKeySpec;
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 secretKeySpec = new SecretKeySpec(key.getBytes(), ALGORITHM);
        Cipher cipher = Cipher.getInstance(TRANSFORMATION);
        cipher.init(Cipher.ENCRYPT_MODE, secretKeySpec);
        byte[] cipherText = cipher.doFinal(plainText.getBytes());
        return Base64.getEncoder().encodeToString(cipherText);
    }

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

其中，`encrypt`方法用于加密明文，`decrypt`方法用于解密密文。`key`参数为密钥，需要保证长度为16、24或32个字节。`plainText`和`cipherText`参数分别为明文和密文，均为字符串类型。在进行加密和解密时，需要用到`SecretKeySpec`和`Cipher`这两个类，按照指定的算法和填充方式进行操作即可。