@NotNull integer parameter

Question

I created an endpoint, and I want to display a message if I don't fill a specific parameter.

For example:

 @NotNull(message = "The distance must be specified.") 
 @QueryParam("distance") 
 final double distance;

But for some reason I don't receive anything if I don't fill the field. Maybe because this is not a String? How should I do?

For example, I want to call the endpoint from Postman. If I did not select the distance parameter there, I want to receive a message: "The distance must be specified." — new_in_programming, Jul 23 '20 at 20:44
No, is not working. But if I change it in Double instead of double it is ok. — new_in_programming, Jul 23 '20 at 20:52
Yes, double is a primitive data type. The default value is 0.0d when you don't pass this. This is expected behaviour. — SKumar, Jul 23 '20 at 20:57

score 1 · Accepted Answer · answered Jul 23 '20 at 20:55

As double value can never be null, this never meets the criteria. If you try with a Wrapper class Double, then this should give your expected result.

@NotNull(message = "The distance must be specified.") 
@QueryParam("distance") 
final Double distance;

score 0 · Answer 2 · answered Jul 23 '20 at 20:56

0

double will always evaluate to 0 in case it doesn't exist, that's why @NotNull is not throwing an exception.

Use Double then if you don't send it, it will null.

answered Jul 23 '20 at 20:56

Eklavya

2 Answers2