The JSON object I'm receiving looks like this:
[{"foo1":"bar1", "foo2":"bar2", "problemkey": "problemvalue"}]
What I'm trying to test for is the existence of problemvalue
. If problemvalue
returns a JSON Object, I'm happy. If it doesn't, it will return as {}
. How do I test for this condition? I've tried several things to no avail.
This is what I've tried thus far:
// if (obj.get("dps") == null) { //didn't work
// if (obj.get("dps").equals("{}")) { //didn't work
if (obj.isNull("dps")) { //didn't work
System.out.println("No dps key");
}
I expected one of these lines to print "No dps key" because {"dps":{}}
, but for whatever reason, it's not. I'm using org.json
. The jar file is org.json-20120521.jar
.
if you want to check for the json empty case, we can directly use below code
String jsonString = {};
JSONObject jsonObject = new JSONObject(jsonString);
if(jsonObject.isEmpty()){
System.out.println("json is empty");
} else{
System.out.println("json is not empty");
}
this may help you.
@Test
public void emptyJsonParseTest() {
JsonNode emptyJsonNode = new ObjectMapper().createObjectNode();
Assert.assertTrue(emptyJsonNode.asText().isEmpty());
}
if (jsonObj != null && jsonObj.length > 0)
To check if a nested JSON object is empty within a JSONObject:
if (!jsonObject.isNull("key") && jsonObject.getJSONObject("key").length() > 0)
If empty array:
.size() == 0
if empty object:
.length() == 0
Try /*string with {}*/ string.trim().equalsIgnoreCase("{}"))
, maybe there is some extra spaces or something
Use the following code:
if(json.isNull()!= null){ //returns true only if json is not null
}
I have added isEmpty() methods on JSONObject and JSONArray()
//on JSONObject
public Boolean isEmpty(){
return !this.keys().hasNext();
}
...
//on JSONArray
public Boolean isEmpty(){
return this.length()==0;
}
you can get it here https://github.com/kommradHomer/JSON-java
Try:
if (record.has("problemkey") && !record.isNull("problemkey")) {
// Do something with object.
}
If you're okay with a hack -
obj.toString().equals("{}");
Serializing the object is expensive and moreso for large objects, but it's good to understand that JSON is transparent as a string, and therefore looking at the string representation is something you can always do to solve a problem.
I would do the following to check for an empty object
obj.similar(new JSONObject())
Object getResult = obj.get("dps");
if (getResult != null && getResult instanceof java.util.Map && (java.util.Map)getResult.isEmpty()) {
handleEmptyDps();
}
else {
handleResult(getResult);
}
A JSON notation {} represents an empty object, meaning an object without members. This is not the same as null. Neither it is string as you are trying to compare it with string "{}". I don't know which json library are you using, but try to look for method something like:
isEmptyObject()
If JSON returned with following structure when records is an ArrayNode:
{}client
records[]
and you want to check if records node has something in it then you can do it using a method size();
if (recordNodes.get(i).size() != 0) {}
For this case, I do something like this:
var obj = {};_x000D_
_x000D_
if(Object.keys(obj).length == 0){_x000D_
console.log("The obj is null")_x000D_
}
_x000D_
Source: Stackoverflow.com