Java语言描述MD5加密工具类实例代码

javascript/296131.html">java;">import java.security.MessageDigest;public class MD5 {	//公盐	private static final String PUBLIC_SALT = "demo" ;	//十六进制下数字到字符的映射数组 	private final static String[] hexDigits = {"0", "1", "2", "3", "4", 	  "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f"};	/**  * 用户密码加密，盐值为 ：私盐+公盐  * @param password 密码  * @param salt 私盐  * @return MD5加密字符串  */	public static String encryptPassword(String password,String salt){		return encodeByMD5(PUBLIC_SALT+password+salt);	}	/**  * md5加密算法  * @param originString  * @return   */	private static String encodeByMD5(String originString){		if (originString != null){			try{				//创建具有指定算法名称的信息摘要 				MessageDigest md = MessageDigest.getInstance("MD5");				//使用指定的字节数组对摘要进行最后更新，然后完成摘要计算 				byte[] results = md.digest(originString.getBytes());				//将得到的字节数组变成字符串返回 				String resultString = byteArrayToHexString(results);				return resultString.toUpperCase();			}			catch(Exception ex){				ex.printStackTrace();			}		}		return null;	}	/**   * 转换字节数组为十六进制字符串   * @param  字节数组   * @return 十六进制字符串   */	private static String byteArrayToHexString(byte[] b){		StringBuffer resultSb = new StringBuffer();		for (int i = 0; i < b.length; i++){			resultSb.append(byteToHexString(b[i]));		}		return resultSb.toString();	}	/** 将一个字节转化成十六进制形式的字符串  */	private static String byteToHexString(byte b){		int n = b;		if (n < 0) 		   n = 256 + n;		int d1 = n / 16;		int d2 = n % 16;		return hexDigits[d1] + hexDigits[d2];	}}