I'm a beginning java programmer, so I'm sorry if my question is kind of dumb.

I have a JSON object that looks like this:

{

"element1" : {

"generated_name_1": {

"a" : {"isReady":false}

},

"generated_name_2":{},

"generated_name_3":{},

"generated_name_4":{}

},

"element2" : {

"generated_name_5" : {

"a" : {"isReady":false},

"g" : {"isReady":false}

}

},

"element3" : {

"a" : { "isReady":false},

"n":{}

}

}

I would like to go through and delete every element that has an empty value associated with it, like "generated_name_2" and "n". I have no idea what the names of those elements would be, and I have no idea how far nested into the JSON tree it is.

I get that I have to write a recursive program, and this is what I came up with:

public static void cleanJsonNodes(ObjectNode myJsonNode){

for (JsonNode currentNode : myJsonNode){

if (currentNode.size() == 0){

myJsonNode.remove(currentNode);

} else {

cleanJsonNodes((ObjectNode)currentNode);

}

}

}

Of course, this doesn't work, but I'm not really sure where to go from here and I've scoured the internet to no avail.

Please someone help me!

解决方案

I want only to show direction how to do that with Json:

JSONObject jsonObj = new JSONObject(_message);

Map map = jsonObj.getMap();

Iterator it = map.keySet().iterator();

while(it.hasNext()){

String key = it.next();

JSONObject o = map.get(key);

if(o.length() == 0){

it.remove();

}

}

When JSONObject loads {} its length is 0, therefore you can drop it.

As A side note, you can use this method in recursion like:

JSONObject jsonObj = new JSONObject(_message);

invoke(jsonObj);

...

private static void invoke(JSONObject jsonObj) {

Map map = jsonObj.getMap();

Iterator it = map.keySet().iterator();

while(it.hasNext()){

String key = it.next();

JSONObject o = map.get(key);

if(o.length() == 0){

it.remove();

}

else{

invoke(o);

}

}

}

I didn't add any validation but for sure , you need to verify instance of jsonObj.getMap() ...