Question

I have a struts action receiving following JSON:

{             
"commandId":"tC",       
"id":"123", 
"def":""
}

Following code works just fine:

JSONObject command = null;
String commandId = null;
String deviceId = null;
try {
  command = new JSONObject(json);
  commandId = command.getString("commandId");
}

Since “def” can be empty, non declared or can contain another array of elements I tried doing this:

JSONObject def = command.getJSONObject("def");

in order to get this JSON object defined in the element def

This only works if def isn’t empty like in this example:

{             
    "commandId":"tC",       
    "id":"123", 
    "def":{"1":"aaa", "2":"bbb"}
}

When def is empty or not defined my program stops working on the line JSONObject def = command.getJSONObject("def"); and noticed that it doesn’t continue the execution?!

If I put JSONObject def = command.getJSONObject("def"); try / catch block I get _JSONObject[“def”] is not a JSONObject _ exception, but execution doesn’t continue

How does JSONObject.getJsonObject(String) behave?

I would expect it to return an empty JSONObject and continue the execution.

What I want is to check if there is anything defined in def and then in a if, else decide what to do in my program according to the value found there… I can’t find a way to make my program work if a client’s json comes with def empty or not defined.

Answer 1

my suggestion is to define “def” either be defined as null or {}:
“def”:null or “def”:{} to align with its usage agreement

quotes is really just used to indicate the value is a string. following the standard might save you and others from confusion in the future.