how read from file and set txte in jTextArea(use IDE netbeans )

if you don't know that, you should:
1. uninstall netbeans
2. learn the basics.

besides the fact that all use of netbeans changes here, is that you get generated crap that is called 'code' for some reason, which is pretty hard to read, let alone maintain (without introducing regression bugs).
from your post, I deduct you don't know how to use methods, nor the api/other documentation.

basic steps are:

  1. read data from file
  2. write text in JTextArea

and sure, you'll need to create subtasks there, but still.

Your question is too vague. Please be more specific. How far have you got with this? What, exactly, is stopping you now?

and what's stopping you from finding that code? It's not as if there's not a gazillion examples of just that out on the web, in tutorials, books, your course notes, etc. etc. etc.