Spring Data - ignore parameter if it has a null value

Question

I want to have a spring data repository interface that takes two parameters. Is there a way to make it have the following behaviour?

MyObject findByParameter         


        

Answer 1

One solution that's missing here is Spring Data JPA's Query By Example feature and leverage the ExampleMatcher#ignoreNullValues, which is built exactly to solve this problem. A custom query and query builder are not necessary.

This Spring Data query:

ExampleMatcher matcher = ExampleMatcher.matching().withIgnoreNullValues();
Example exampleQuery = Example.of(new MyObject("foo", null), matcher);
List results = repository.findAll(exampleQuery);

Yields a query that looks like:

select * 
from myObject 
where parameter1 = "foo"

While the following:

ExampleMatcher matcher = ExampleMatcher.matching().withIgnoreNullValues();
Example exampleQuery = Example.of(new MyObject("foo", "bar"), matcher);
List results = repository.findAll(exampleQuery);

Yields:

select * 
from myObject 
where parameter1 = "foo"
and parameter2 = "bar"

Very cool!

Note: One thing you'll have to do to your Repository interface is add the QueryByExample interface. You can do this either by extending the QueryByExample interface directly, or implicity via the JpaRepository:

public interface MyObjectRepository extends JpaRepository {}