code: public static String decypt(byte[] b, byte[] key) {
          String _str = null;
          try {
              SecretKey secretKey = new SecretKeySpec(key, "AES");
              Cipher cipher = Cipher.getInstance("AES");
              cipher.init(Cipher.DECRYPT_MODE, secretKey);
              _str = new String(cipher.doFinal(b));
          } catch (Exception e) {
              throw new RuntimeException(e);
          }
          return _str;
      }
docs: 将一个字符串按指定key进行AES解密并返回
  
  @param b   需要解密的字符串
  @param key 指定key
  @return 返回解密后的字符串，失败返回null