How to test if JSON object is empty in Java

Question

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

User · Answer

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.

User · Answer

For this case  I do something like this     x000D   x000D  var obj       x000D   x000D  if Object keys obj  length    0   x000D          console log  The obj is null   x000D    x000D   x000D   x000D

User · Answer

if  jsonObj    null  amp  amp  jsonObj length  gt  0    To check if a nested JSON object is empty within a JSONObject   if   jsonObject isNull  key    amp  amp  jsonObject getJSONObject  key   length    gt  0

User · Answer

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

User · Answer

Try   if  record has  problemkey    amp  amp   record isNull  problemkey             Do something with object

User · Answer

Test public void emptyJsonParseTest         JsonNode emptyJsonNode   new ObjectMapper   createObjectNode        Assert assertTrue emptyJsonNode asText   isEmpty

User · Answer

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

User · Answer

Use the following code   if json isNull     null      returns true only if json is not null

User · Answer

Try   string with      string trim   equalsIgnoreCase         maybe there is some extra spaces or something

User · Answer

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

User · Answer

Object getResult   obj get  dps     if  getResult    null  amp  amp  getResult instanceof java util Map  amp  amp   java util Map getResult isEmpty          handleEmptyDps        else       handleResult getResult

User · Answer

obj length      0   is what I would do

User · Answer

If empty array    size      0   if empty object    length      0

User · Answer

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

User · Answer

I would do the following to check for an empty object  obj similar new JSONObject

[java] How to test if JSON object is empty in Java

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