How to check if a json key exists?

Question

So, I get some JSON values from the server but I don\'t know if there will be a particular field or not.

So like:

{ \"regatta_name\":\"ProbaRegatta\"         


        

Answer 1

Json has a method called containsKey().

You can use it to check if a certain key is contained in the Json set.

File jsonInputFile = new File("jsonFile.json"); 
InputStream is = new FileInputStream(jsonInputFile);
JsonReader reader = Json.createReader(is);
JsonObject frameObj = reader.readObject();
reader.close();

if frameObj.containsKey("person") {
      //Do stuff
}