AES对称加密解密类

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;
   }
}