Dumping a java object's properties

Question

Is there a library that will recursively dump/print an objects properties? I'm looking for something similar to the console.dir() function in Firebug.

I'm aware of the commons-lang ReflectionToStringBuilder but it does not recurse into an object. I.e., if I run the following:

public class ToString {

    public static void main(String [] args) {
        System.out.println(ReflectionToStringBuilder.toString(new Outer(), ToStringStyle.MULTI_LINE_STYLE));
    }

    private static class Outer {
        private int intValue = 5;
        private Inner innerValue = new Inner();
    }

    private static class Inner {
        private String stringValue = "foo";
    }
}

I receive:

ToString$Outer@1b67f74[ intValue=5
innerValue=ToString$Inner@530daa ]

I realize that in my example, I could have overriden the toString() method for Inner but in the real world, I'm dealing with external objects that I can't modify.

Answer 1

You could try XStream.

XStream xstream = new XStream(new Sun14ReflectionProvider(
  new FieldDictionary(new ImmutableFieldKeySorter())),
  new DomDriver("utf-8"));
System.out.println(xstream.toXML(new Outer()));

prints out:

<foo.ToString_-Outer>
  <intValue>5</intValue>
  <innerValue>
    <stringValue>foo</stringValue>
  </innerValue>
</foo.ToString_-Outer>

You could also output in JSON

And be careful of circular references ;)