简单的ASE加密解密功能

import javax.crypto.Cipher;import javax.crypto.KeyGenerator;import javax.crypto.SecretKey;import java.security.Security;/* *简单的ASE加密解密功能 */public class emisSecurity {  private static KeyGenerator keygen ;  private static SecretKey secretKey;  private static Cipher cipher;  private static emisSecurity security = null;  private emisSecurity(){  }  public static emisSecurity getInstance() throws Exception{      if(security == null){        security = new emisSecurity();        keygen = KeyGenerator.getInstance("AES");        secretKey = keygen.generateKey();        cipher =Cipher.getInstance("AES");      }    return security;  }  //加密  public String encrypt(String str) throws Exception{    cipher.init(Cipher.ENCRYPT_MODE,secretKey);    byte [] src =  str.getBytes();    byte [] enc = cipher.doFinal(src);    return parseByte2HexStr(enc);  }  //解密  public String decrypt(String str) throws Exception{    cipher.init(Cipher.DECRYPT_MODE,secretKey);    byte[] enc = parseHexStr2Byte(str);    byte [] dec = cipher.doFinal(enc);    return new String(dec);  }  /**将16进制转换为二进制   * @param hexStr   * @return   */  public static byte[] parseHexStr2Byte(String hexStr) {    if (hexStr.length() < 1)      return null;    byte[] result = new byte[hexStr.length()/2];    for (int i = 0;i< hexStr.length()/2; i++) {      int high = Integer.parseInt(hexStr.substring(i*2, i*2+1), 16);      int low = Integer.parseInt(hexStr.substring(i*2+1, i*2+2), 16);      result[i] = (byte) (high * 16 + low);    }    return result;  }  /**将二进制转换成16进制   * @param buf   * @return   */  public static String parseByte2HexStr(byte buf[]) {    StringBuffer sb = new StringBuffer();    for (int i = 0; i < buf.length; i++) {      String hex = Integer.toHexString(buf[i] & 0xFF);      if (hex.length() == 1) {        hex = '0' + hex;      }      sb.append(hex.toUpperCase());    }    return sb.toString();  }  public static void main(String[] args) throws Exception{    String str = "select * from users 我";    String ss =  emisSecurity.getInstance().encrypt(str) ;    System.out.println(ss);    System.out.println(emisSecurity.getInstance().decrypt(ss));  }}