How To Format (parse) Json File

I have written my program result into a json file but i am getting json file in below format.
 
{"one":"one","two":"two","three":"three"}
 
but I have lot of entries to write into json finally it become unreadle format which is not very compart to read.
 
Is there any way to format or writing line by line into json file like below format,
 
{
"one":"one",
"two":"two",
"three":"three"
}