import java.io.UnsupportedEncodingException;

import javax.crypto.Cipher;

import javax.crypto.spec.SecretKeySpec;

///** AES对称加密解密类 **/

public class Aes {

   // /** 算法/模式/填充 **/

   private static final String CipherMode = "AES/ECB/PKCS5Padding";

   ///** 创建密钥 **/

   private static SecretKeySpec createKey(String password) {

      byte[] data = null;

      if (password == null) {

         password = "";

      }

      StringBuffer sb = new StringBuffer(32);

      sb.append(password);

      while (sb.length() < 32) {

         sb.append("0");

      }

      if (sb.length() > 32) {

         sb.setLength(32);

      }

      try {

         data = sb.toString().getBytes("UTF-8");

      } catch (UnsupportedEncodingException e) {

         e.printStackTrace();

      }

      return new SecretKeySpec(data, "AES");

   }

   // /** 加密字节数据 **/

   public static byte[] encrypt(byte[] content, String password) {

      try {

         SecretKeySpec key = createKey(password);

         System.out.println(key);

         Cipher cipher = Cipher.getInstance(CipherMode);

         cipher.init(Cipher.ENCRYPT_MODE, key);

         byte[] result = cipher.doFinal(content);

         return result;

      } catch (Exception e) {

         e.printStackTrace();

      }

      return null;

   }

   ///** 加密(结果为16进制字符串) **/

   public static String encrypt(String content, String password) {

      byte[] data = null;

      try {

         data = content.getBytes("UTF-8");

      } catch (Exception e) {

         e.printStackTrace();

      }

      data = encrypt(data, password);

      String result = byte2hex(data);

      return result;

   }

   // /** 解密字节数组 **/

   public static byte[] decrypt(byte[] content, String password) {

      try {

         SecretKeySpec key = createKey(password);

         Cipher cipher = Cipher.getInstance(CipherMode);

         cipher.init(Cipher.DECRYPT_MODE, key);

         byte[] result = cipher.doFinal(content);

         return result;

      } catch (Exception e) {

         e.printStackTrace();

      }

      return null;

   }

   ///** 解密16进制的字符串为字符串 **/

   public static String decrypt(String content, String password) {

      byte[] data = null;

      try {

         data = hex2byte(content);

      } catch (Exception e) {

         e.printStackTrace();

      }

      data = decrypt(data, password);

      if (data == null)

         return null;

      String result = null;

      try {

         result = new String(data, "UTF-8");

      } catch (UnsupportedEncodingException e) {

         e.printStackTrace();

      }

      return result;

   }

   // /** 字节数组转成16进制字符串 **/

   public static String byte2hex(byte[] b) { // 一个字节的数，

      StringBuffer sb = new StringBuffer(b.length * 2);

      String tmp = "";

      for (int n = 0; n < b.length; n++) {

         // 整数转成十六进制表示

         tmp = (Integer.toHexString(b[n] & 0XFF));

         if (tmp.length() == 1) {

            sb.append("0");

         }

         sb.append(tmp);

      }

      return sb.toString().toUpperCase(); // 转成大写

   }

   // /** 将hex字符串转换成字节数组 **/

   private static byte[] hex2byte(String inputString) {

      if (inputString == null || inputString.length() < 2) {

         return new byte[0];

      }

      inputString = inputString.toLowerCase();

      int l = inputString.length() / 2;

      byte[] result = new byte[l];

      for (int i = 0; i < l; ++i) {

         String tmp = inputString.substring(2 * i, 2 * i + 2);

         result[i] = (byte) (Integer.parseInt(tmp, 16) & 0xFF);

      }

      return result;

   }

}