week11-- 作业

/** * SHA加密算法加盐 * @author mcrking * */public class SHAUtil {	    /**      * SHA     * @param msg      * @return      */      public static String encryptSHA(String msg,String salt) {      	StringBuilder sb = new StringBuilder();      	try{      		MessageDigest md = MessageDigest.getInstance("SHA-1");      		md.update(salt.getBytes());      		byte[] bytes = md.digest(msg.getBytes());      		for(int i=0; i< bytes.length ;i++){      			sb.append(Integer.toString((bytes[i] & 0xff) + 0x100, 16).substring(1));      		}      	}catch(Exception e){      		    	}      	    	return sb.toString().trim();      }  	    /**     * 获取sha的salt     * @return     */    public static String getSaltSHA1(){          SecureRandom sr;          byte[] salt = new byte[16];          try {              sr = SecureRandom.getInstance("SHA1PRNG");               sr.nextBytes(salt);          } catch (NoSuchAlgorithmException e) {              e.printStackTrace();          }                    return salt.toString();      }  	        Boolean checkPW（String userId ,String pwd){       boolean flag = false;    	 User user = UserServer.getUserInfo(String userId);       String newPwd = encryptSHA(pwd ,user.getSalt());        if(newPwd.equals(user.getPwd()){       	flag = true;       }              return flag;    }