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creating uuid's or similar based on a string

alex hendry

Joined: Jul 24, 2011
Posts: 4
Hi all,

I have written a web crawler that crawls tube sites. Each tube it finds it grabs the thumbnails for to show in search results and these are stored on my server. At the moment for each tube I find I create a folder name based on a random uuid and store the thumbnails in that folder. I then store that uuid with the url of the tube so I know where the images for the tube are.

This is not good because if I ever lost some of my data that associates the url with the random uuid named folder it would be hard to rebuild.

I want to create a uuid or similar based upon the url and then use that as the folder name. This way if I lost the associting data I could rebuild by regenerating the uuid of the url and then finding that folder.

I have looked at the uuid api and I can use the UUID.nameUUIDFromBytes() method by creating a byte[] from the url and converting it into a uuid but I cant convert the uuid back to the url.

Using the url for a folder name results in to long folder names and urls have to many charecters that dont make for good folder names.

I have also thought about converting the url to a byte[] then using the bytes concatenated as the folder name but this results in the folder name being to long.

Any ideas???
Anantha Sharma
Ranch Hand

Joined: Sep 01, 2010
Posts: 43

why don't you look at building a pattern
for example if you download an image from say then you can store the files in a folder structure like /google-images-foo-bar/mypic-thumb.jpg

this way you'll be able to retrieve the weburl by simply analyzing the folder name.. again there are lots of things to be considered, like '-' in the URL etc.,

this could be a start for you to look at things differently...
It is sorta covered in the JavaRanch Style Guide.
subject: creating uuid's or similar based on a string
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