1. import lombok.extern.slf4j.Slf4j;
    2. import java.security.MessageDigest;
    3. import java.util.Random;
    5. @Slf4j
    6. public  class Md5Util {
    7.     private static byte[] md5(String s) {
    8.         MessageDigest algorithm;
    9.         try {
    10.             algorithm = MessageDigest.getInstance("MD5");
    11.             algorithm.reset();
    12.             algorithm.update(s.getBytes("UTF-8"));
    13.             byte[] messageDigest = algorithm.digest();
    14.             return messageDigest;
    15.         } catch (Exception e) {
    16.             log.error("MD5 Error...", e);
    17.         }
    18.         return null;
    19.     }
    21.     private static final String toHex(byte hash[]) {
    22.         if (hash == null) {
    23.             return null;
    24.         }
    25.         StringBuffer buf = new StringBuffer(hash.length * 2);
    26.         int i;
    27.         for (i = 0; i < hash.length; i++) {
    28.             if ((hash[i] & 0xff) < 0x10) {
    29.                 buf.append("0");
    30.             }
    31.             buf.append(Long.toString(hash[i] & 0xff, 16));
    32.         }
    33.         return buf.toString();
    34.     }
    36.     public static String hash(String s) {
    37.         try {
    38.             return new String(toHex(md5(s)).getBytes("UTF-8"), "UTF-8");
    39.         } catch (Exception e) {
    40.             log.error("not supported charset...{}", e);
    41.             return s;
    42.         }
    43.     }
    45.     /**
    46.      * 对密码按照用户名，密码，盐进行加密
    47.      * @param username 用户名
    48.      * @param password 密码
    49.      * @param salt 盐
    50.      * @return
    51.      */
    52.     public static String encryptPassword(String username, String password, String salt) {
    53.         return Md5Util.hash(username + password + salt);
    54.     }
    56.     /**
    57.      * 对密码按照密码，盐进行加密
    58.      * @param password 密码
    59.      * @param salt 盐
    60.      * @return
    61.      */
    62.     public static String encryptPassword(String password, String salt) {
    63.         return Md5Util.hash(password + salt);
    64.     }
    66.     /**
    67.      * 生成salt的静态方法
    68.      * @param n
    69.      * @return
    70.      */
    71.     public static String getSalt(int n){
    72.         char[] chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!@#$%^&*()".toCharArray();
    73.         StringBuilder sb = new StringBuilder();
    74.         for (int i=0;i<n;i++){
    75.             char aChar = chars[new Random().nextInt(chars.length)];
    76.             sb.append(aChar);
    77.         }
    78.         return sb.toString();
    79.     }
    80. }