URL shortening algorithm

java url url-shortener
Bozho picture Bozho · Jan 1, 2011 · Viewed 27.3k times · Source

Now, this is not strictly about URL shortening, but my purpose is such anyway, so let's view it like that. Of course the steps to URL shortening are:

  1. Take the full URL
  2. Generate a unique short string to be the key for the URL
  3. Store the URL and the key in a database (a key-value store would be a perfect match here)

Now, about the second point. Here's what I've come up with:

ByteArrayOutputStream baos = new ByteArrayOutputStream();
DataOutputStream dos = new DataOutputStream(baos);
UUID uuid = UUID.randomUUID();
dos.writeLong(uuid.getMostSignificantBits());
String encoded = new String(Base64.encodeBase64(baos.toByteArray()), "ISO-8859-1");
String shortUrlKey = StringUtils.left(encoded, 6); // returns the leftmost 6 characters
// check if exists in database, repeat until it does not

Is this good enough?

Answer

Uwe Keim picture Uwe Keim · Jan 1, 2011

For a file upload application I wrote, I needed this functionality, too. Having read this SO article, I decided to stick with just some random numbers and check whether they exists in the DB.

So your aproach is similar to what I did.

Related questions

Java URL encoding of query string parameters

Say I have a URL http://example.com/query?q= and I have a query entered by the user such as: random word £500 bank $ I want the result to be a properly encoded URL: http://example.com/query?q=random%20…

Read More
How to get parameters from the URL with JSP

In JSP how do I get parameters from the URL? For example I have a URL www.somesite.com/Transaction_List.jsp?accountID=5 I want to get the 5. Is there a request.getAttribute( "accountID" ) like there is for sessions or …

Read More
Simplest way to read json from a URL in java

This might be a dumb question but what is the simplest way to read and parse JSON from URL in Java? In Groovy, it's a matter of few lines of code. Java examples that I find are ridiculously long (and …

Read More