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LINQ Reporting Engine - How to check if a JSON key is null

I’m using the LINQ engine to create a word document, through a json file. I use java, and Aspose version 21.11. I would like to access a field only when other than null, so:

<< if [saldo.atStrumentiByCodStrum !=null]>>
<< [saldo.atStrumentiByCodStrum.desShort]>>
<< /if >>

but I have a nullPointerException at runtime.

resources.zip (239.3 KB)


Internally, JSON objects are deserialized into ADO.NET objects (in Java, you can find those within the com.aspose.words.net.System.Data package). In you example, atStrumentiByCodStrum is deserialized into a collection of rows related to the children table. Although atStrumentiByCodStrum is set to null for the first item in your JSON file, internally, it becomes an empty collection of rows that is not null, so comparison against null does not work.

To access desShort only when atStrumentiByCodStrum represents a non-empty collection of rows, you can use the following syntax:

<<if [saldo.atStrumentiByCodStrum.count() == 1]>>

I have modified your template to show this. Please check testJsonNull Modified.docx (248.0 KB).