Search for all files in project containing the text ‘querystring’ in Eclipse

Yes, you can do this quite easily. Click on your project in the project explorer or Navigator, go to the Search menu at the top, click File…, input your search string, and make sure that ‘Selected Resources’ or ‘Enclosing Projects’ is selected, then hit search. The alternative way to open the window is with Ctrl-H. This may depend on your keyboard accelerator configuration.

More details: http://www.ehow.com/how_4742705_file-eclipse.html and http://www.avajava.com/tutorials/lessons/how-do-i-do-a-find-and-replace-in-multiple-files-in-eclipse.html

_{(source: avajava.com)}