Scanning the web for links

I was just wondering if their is a way to开发者_如何学JAVA scan the web to find out every website that has a link to my website.

Say scan the web for every website that has a link to www.example.com ???

Is their a tool to do this.

Massive task, don't reinvent the wheel, use google webmaster tools:

https://www.google.com/webmasters/tools/

Edit: If you wanted to do it yourself you'd have to text index and datamine the whole internets. You'd be long dead before you got close to finishing this.