Access nested json data in single get?

Question

I am trying to trying to get a value out of a json object. How would I get a third level json object:

json format looks like:

feedString = {"level1":[{"level2":{"level3":{"valueIWant":10}}}]}

Code is:

JSONObject  jsonFeed = new JSONObject(feedString);
jsonFeed.get("level1.level2.level3.valueIWant");

Can I get nested levels in one get? What should my key look like?

Answer 1

You could give JSONiJ (JSON in Java) a shot; it's a Java version of JSONPath and basically maps (a subset of) XPath syntax onto JSON objects.

Also, see this SO question for some other ideas; it looks like json-path has a Java version, and uses dot notation.

The other option is to build an EL bridge between JSONObjects and something like MVEL or OGNL, which would give you the more-familiar dot notation. (I thought there was an MVEL/JSON bridge, but can't find it now.)

Answer 2

You should use JSONPath. Check out this Java implementation http://code.google.com/p/json-path/

Answer 3

It's been a while now, but I have some good news. Just tried beanutils and it works like a charm! Assuming you have the json converted to map: (any parser can do that)

private Map<String, Object> json;

All you need is:

PropertyUtils.getProperty(json, "level1.level2.level3.valueIWant")

Have fun :)