How to pretty print a complex Java object (e.g. with fields that are collections of objects)? [closed]

Question

I'm looking for a library function (ideally from a commonly used framework e.g. Spring, Guava, Apache Commons etc.) that will nicely print the values of any Java object.

This is a general question rather than a specific one. Have seen similar questions on StackOverflow for which a common answer is "implement your own toString() method on the class" but this option isn't always practical - am looking for a general way of doing this with any object I come across, which may originate from third party code. Another suggestion is to use RefectionToStringBuilder from Apache Commons, e.g:

new ReflectionToStringBuilder(complexObject, new RecursiveToStringStyle()).toString()

But this has limited use - e.g. when it comes across a collection it tends to output something like this:

java.util.ArrayList@fcc7ab1[size=1]

An actual use case example is to log an Iterable<PushResult> returned from JGit's pushCommand.call() method - if posting an answer please make sure it would work with this as well as any other complex object.

Answer 1

You could try and use Gson. it also serializes Arrays, Maps or whatever....

MyObject myObject = new MyObject();
Gson gson = new GsonBuilder().setPrettyPrinting().serializeNulls().create();
gson.toJson(myObject);

For deserialization use:

gson.fromJson(MyObject.class);

For typed maps see this answer: Gson: Is there an easier way to serialize a map