A small Java library for pretty-printing JSON data.
This project is free and unencumbered public domain software. Feel free (and I encourage you) to do anything you want with it. You do not even have to give any credit.
The diagrams directory contains explanatory diagrams to help you
understand the algorithms in case you are not well-versed in Java.
Look for tokenization.png and prettyprinting.png. All diagrams are generated from their respective
PlantUML descriptions. (*.puml files)
Simply copy and paste the classes into your project. Modify them to your liking and to fit your needs. The project also contains unit and integration tests which can be useful to you.
Note, that the pretty-printer presumes that the passed JSON data is valid. It does not perform any validation on the input.
In one of my hobby projects I generate JSON data, and I wished to pretty-print it. Because I wanted to keep external dependencies to a minimum, it seemed as an overkill to use any of the big JSON libraries (e.g. Jackson, Gson, even JSON-Java (org.json)) just for that. I quickly looked around the web, and I found no general algorithm or small library that I could use. That is why I created this small utility to fill this gap.
As I mentioned above, the pretty-printer does not validate JSON data. Why? Because this library is primarily for my other project where I am generating data: and I make sure that only valid data is generated. If I also wanted to validate data I would have to write a full-fledged JSON parser — which, again, seemed as an overkill. (Even generating one with ANTLR or other similar tools.)
The project is in Java 11, but with some minor modifications it can be backported to Java 8. The tests use JUnit 5.
Gábor Némethi - nemethi
Project - https://github.com/nemethi/json-pretty-printer
This project is released into the public domain. See the UNLICENSE file for more information.