字符串加密与解密

 package service;
public class Test {
 /**
  * 给字符串加密与解密DEMO
  * @param args
  * @throws Exception 
  */
 public static void main(String[] args) throws Exception {
  String str ="我是中国人，我爱自己的祖国！";
  //加密
  str = DES.encode(str, "LEO");
  System.out.println(str);
  //解密
  str = DES.decode(str, "LEO");
  System.out.println(str);
 }
}
=====================================输出结果=====================================
66fe21f5f9e6e10771128e627c9977f664896be4d9afae5143c0f48570b332b15e4f26949a28b1764bdbde4e58b2ba8e
我是中国人，我爱自己的祖国！
=================================================================================




package service;
import java.security.Key;
import javax.crypto.Cipher;
public class DES {
 public static String decode(String str,String str_key) throws Exception {
  Key key=getKey(str_key);
  Cipher decryptCipher = Cipher.getInstance("DES");
     decryptCipher.init(Cipher.DECRYPT_MODE, key);
  str= new String(decryptCipher.doFinal(hexStr2ByteArr(str)));
  return str;
 } 
 
 public static String encode(String str,String str_key) throws Exception{
  Key key=getKey(str_key);
  Cipher encryptCipher = Cipher.getInstance("DES");
  encryptCipher.init(Cipher.ENCRYPT_MODE, key);
  str=byteArr2HexStr(encryptCipher.doFinal(str.getBytes()));
  return str;
 }
 
 
 private static Key getKey(String str) throws Exception {
  byte[] arrBTmp=str.getBytes();
     byte[] arrB = new byte[8];
     for (int i = 0; i < arrBTmp.length && i < 8; i++) {
       arrB[i] = arrBTmp[i];
     }
     Key key = new javax.crypto.spec.SecretKeySpec(arrB, "DES"); 
     return key;
   }
   private static byte[] hexStr2ByteArr(String strIn) throws Exception {
     byte[] arrB = strIn.getBytes();
     int iLen = arrB.length;
     byte[] arrOut = new byte[iLen / 2];    
     for (int i = 0; i < iLen; i = i + 2) {
       String strTmp = new String(arrB, i, 2);
       arrOut[i / 2] = (byte) Integer.parseInt(strTmp, 16);
     }
     return arrOut;
   }
   
   private static String byteArr2HexStr(byte[] arrB) throws Exception {
     int iLen = arrB.length;    
     StringBuffer sb = new StringBuffer(iLen * 2);
     for (int i = 0; i < iLen; i++) {
       int intTmp = arrB[i];      
       while (intTmp < 0) {       
         intTmp = intTmp + 256;
       }
       if (intTmp < 16) {
         sb.append("0");
       }
       sb.append(Integer.toString(intTmp, 16));
     }
     return sb.toString();
   }
   
   
}