AES是一种对称的加密和解密的算法，其用法如下：

package com.zys.demo.util;

import lombok.extern.slf4j.Slf4j;

import javax.crypto.Cipher;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.util.Base64;

/**
 * aes加密与解密，对称的
 */
@Slf4j
public class AesUtil {

    private static final Base64.Decoder decoder = Base64.getDecoder();
    private static final Base64.Encoder encoder = Base64.getEncoder();
    private static final String DEFAULT_CIPHER_ALGORITHM = "AES/CBC/PKCS5Padding";

    /**
     * 加密
     *
     * @param str 加密前的字符串
     * @param key 加密KEY
     * @return
     */
    public static String encrypt(String str, String key) throws Exception {
        if (key == null) {
            log.warn("Key为空null");
            return null;
        } else if (key.length() != 16) {
            log.warn("Key长度不是16位");
            return null;
        }
        byte[] raw = key.getBytes("utf-8");
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
        IvParameterSpec iv = new IvParameterSpec(key.getBytes());
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec, iv);
        byte[] encrypted = cipher.doFinal(str.getBytes());
        String encodedText = encoder.encodeToString(encrypted);
        return encodedText;

    }

    /**
     * 解密
     *
     * @param str 解密前的字符串
     * @param key 解密KEY
     * @return
     * @throws Exception
     */
    public static String decrypt(String str, String key) throws Exception{
        // 判断Key是否正确
        if (key == null) {
            log.warn("Key为空null");
            return null;
        } else if (key.length() != 16) {
            log.warn("Key长度不是16位");
            return null;
        }
        byte[] raw = key.getBytes("utf-8");
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
        IvParameterSpec iv = new IvParameterSpec(key.getBytes());
        cipher.init(Cipher.DECRYPT_MODE, skeySpec, iv);
        byte[] encrypted1 = decoder.decode(str);
        byte[] original = cipher.doFinal(encrypted1);
        String originalString = new String(original);
        return originalString;
    }

    public static void main(String[] args) throws Exception {
        String cKey = "2021071410123066";
        // 需要加密的字串
        String str = "123456";
        String enString = encrypt(str, cKey);
        String DeString = decrypt(enString, cKey);
    }
}

在使用时，需要给其指定加密和解密的盐值，且长度必须是16位。