Loose Precision when retrieve data from rest web service

Hi,

I use a rest service from jasper studio.
My data is for example : "5.65" (In JSON format)
When i click on Data preview , it show only '5'.  (The field is BigDecimal)

In my web service, if i change the mysql query with

The JSON become : '5,65' and it works ...

How can i cast this value in Jasper to avoid the use of replace...

Thanks