java实现MD5加密算法详解编程语言

import java.io.UnsupportedEncodingException; 
import java.security.MessageDigest; 
import java.security.NoSuchAlgorithmException; 
public class MD5Util { 
      public static String generateMD5(String input) 
      { 
        MessageDigest messageDigest = null; 
        try { 
          messageDigest = MessageDigest.getInstance("MD5"); 
          messageDigest.reset(); 
          messageDigest.update(input.getBytes("UTF-8")); 
        } catch (NoSuchAlgorithmException e) { 
          System.out.println("NoSuchAlgorithmException caught!"); 
          System.exit(-1); 
        } catch (UnsupportedEncodingException e) { 
          e.printStackTrace(); 
        } 
        byte[] byteArray = messageDigest.digest(); 
        StringBuffer md5StrBuff = new StringBuffer(); 
        for (int i = 0; i < byteArray.length; i++) { 
          if (Integer.toHexString(0xFF & byteArray[i]).length() == 1) 
            md5StrBuff.append("0").append(Integer.toHexString(0xFF & byteArray[i])); 
          else { 
            md5StrBuff.append(Integer.toHexString(0xFF & byteArray[i])); 
          } 
        } 
        return md5StrBuff.toString(); 
      } 
    }