Create MD5 hash in JSP

String plainText = "123456";
MessageDigest mdAlgorithm = MessageDigest.getInstance("MD5");
mdAlgorithm.update(plainText.getBytes());

byte[] digest = mdAlgorithm.digest();
StringBuffer hexString = new StringBuffer();

for (int i = 0; i < digest.length; i++) {
    plainText = Integer.toHexString(0xFF & digest[i]);

    if (plainText.length() < 2) {
        plainText = "0" + plainText;
    }

    hexString.append(plainText);
}

out.print(hexString.toString());
Published May 19, 2004 · Updated September 17, 2005

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9 Comments · RSS feed
1
flip said on September 27, 2005

IMHO a very nice solution, all the others I've seen so far involve pages of code or some obscure libraries. Thank You!

2
Viktor said on December 19, 2005

I have been looking for this a long time, thanks!

3
Fuzz said on February 20, 2006

great solution!
import java.security

4
gid said on June 01, 2006

Works like a charm, the solution I was using,

String md5 = new BigInteger( 1, md.digest() ).toString(16);

wanted to truncated leading 0's, this one doesn't.

5
said on August 30, 2006

I used your code but modified it so I can hash strings and other objects.


    public static String getHash(Object o)
    {
    	try
    	{
    		MessageDigest mdAlgorithm = MessageDigest.getInstance("MD5");
    		ByteArrayOutputStream baos = new ByteArrayOutputStream();
    		ObjectOutputStream oos = new ObjectOutputStream(baos);
    		oos.writeObject(o);
    		mdAlgorithm.update(baos.toByteArray());

    		byte[] digest = mdAlgorithm.digest();
    		StringBuffer hexString = new StringBuffer();

    		for (int i = 0; i < digest.length; i++)
    		{
    			String x = Integer.toHexString(0xFF & digest[i]);
    			if (x.length() < 2) x = "0" + x;
    			hexString.append(x);
    		}
    		return(hexString.toString());
    	}
    	catch(NoSuchAlgorithmException e) { return(null); }
    	catch(IOException e) { return(null); }
    }
6
Patrick said on October 27, 2006

Thanks! This solution saves me some time ;)

7
d said on November 18, 2006

<script>
var i=0;
while (var<5)
{
documnet.write("Hello World!");
var=var+1;
}
</script>

8
Jon Cram said on December 06, 2006

Excellent example!

I'm just starting out building Java apps and need to add some authentication.

I decided upon storing user details in a plain text file (college project - simplest option - not allowed to use a DB) and wanted to shadow passwords. Now I can!

9
Brian said on February 19, 2007

nice job!!!

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