md5加密算法原理java_java实现MD5加密算法详解

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();

}

}