MD5介绍【链接】

Java代码实现

 1 public class Md5Util {
 2     private String Md5Util(String s) {
 3         try {
 4             MessageDigest md = MessageDigest.getInstance("MD5");
 5             byte[] bytes = md.digest(s.getBytes("utf-8"));
 6             return toHex(bytes);
 7         } catch (Exception e) {
 8             throw new RuntimeException(e);
 9         }
10     }
11 
12     private static String toHex(byte[] bytes) {
13 
14         final char[] HEX_DIGITS = "0123456789abcdef".toCharArray();
15         StringBuilder ret = new StringBuilder(bytes.length * 2);
16         for (int i = 0; i < bytes.length; i++) {
17             ret.append(HEX_DIGITS[(bytes[i] >> 4) & 0x0f]);
18             ret.append(HEX_DIGITS[bytes[i] & 0x0f]);
19         }
20         return ret.toString();
21     }
22 }