Free(or paid, but prefer free) C++ library for get text infomation out of PDF file?

I get a small project to work, the step one is extract information from more than 1000 PDF files.

Is there any good free C++ library I can study and use to search text in PDF, load relative information into memory and write into db or csv.? Since I am studying the C++, I think trying to use c++ as much as possible is a good thing for me.

Thanks a lot!
I guess so, it is essential file i/o and string manipulation. But I never code against PDF file before...

Have no idea. Maybe c# is better for this task. Looks like there're some third-party library can parse the content according to the PDF object model into XML data, and developer can manipulate the data from there