How to write to a text file one line at a time?

Question

Java

How to write to a text file one line at a time?
And how can you find a substring in a particular file?
Script plz...

Answer 1

Writing line by line
www.java2s.com/Tutorial/Java/0180__File/Writelines...
To find a substring, read the file
www.java2s.com/Code/Android/File/GetFileContentsas...
Find a substring elementarily
str.contains(str2)
Use the power of google and java2s, I recommend)