How to configure query by example to include null values? - spring-data-jpa

Question

I have the following matcher:
Example.of(
user,
ExampleMatcher.matching()
.withMatcher("name", contains().ignoreCase())
.withMatcher("phoneNumber", contains())
)
It works fine except null values. For example, it doesn't return the users whose phone number is NULL.
I have tried to following to include the NULL values but it didn't work:
Example.of(
user,
ExampleMatcher.matching()
.withMatcher("name", contains().ignoreCase())
.withIncludeNullValues()
.withMatcher("phoneNumber", contains())
.withIncludeNullValues()
)
The generated SQL is the following:
select
user0_.id as id1_9_,
user0_.document_expiry_date as document2_9_,
user0_.document_type as document3_9_,
user0_.document_url as document4_9_,
user0_.email as email5_9_,
user0_.name as name6_9_,
user0_.phone_number as phone_nu7_9_
from
user user0_
where
(lower(user0_.name) like ?)
and (user0_.id is null)
and (user0_.document_type is null)
and (user0_.document_url is null)
and (user0_.email is null)
and (user0_.phone_number like ?)
and (user0_.document_expiry_date is null)
How can I configure it to include rows with NULL columns as well?

Answer 1

Confronted the same problem, but I think there is no way to accomplish this goal. Here is the source code of method withMatcher:
public ExampleMatcher withMatcher(String propertyPath, ExampleMatcher.GenericPropertyMatcher genericPropertyMatcher) {
Assert.hasText(propertyPath, "PropertyPath must not be empty!");
Assert.notNull(genericPropertyMatcher, "GenericPropertyMatcher must not be empty!");
ExampleMatcher.PropertySpecifiers propertySpecifiers = new ExampleMatcher.PropertySpecifiers(this.propertySpecifiers);
ExampleMatcher.PropertySpecifier propertySpecifier = new ExampleMatcher.PropertySpecifier(propertyPath);
if (genericPropertyMatcher.ignoreCase != null) {
propertySpecifier = propertySpecifier.withIgnoreCase(genericPropertyMatcher.ignoreCase);
}
if (genericPropertyMatcher.stringMatcher != null) {
propertySpecifier = propertySpecifier.withStringMatcher(genericPropertyMatcher.stringMatcher);
}
if (genericPropertyMatcher.valueTransformer != null) {
propertySpecifier = propertySpecifier.withValueTransformer(genericPropertyMatcher.valueTransformer);
}
propertySpecifiers.add(propertySpecifier);
return new ExampleMatcher(this.nullHandler, this.defaultStringMatcher, propertySpecifiers, this.ignoredPaths, this.defaultIgnoreCase, this.mode);
}
this method returns a ExampleMatcher with the 'global' nullHandler which applied to all the fields. That means, you can't specify a different nullHander for some special fields.

Answer 2

You can implements JpaSpecificationExecutor<T> in your repository and use findAll(Specification specification), and set like param:
//My solution, create a specification with predicate and add example.
public Specification<MaestroPlasticoTebca> specificationAttributeNull(boolean isNull, Example<MaestroPlasticoTebca> example, String attributeName) {
return (root, query, builder) -> {
final List<Predicate> predicates = new ArrayList<>();
if (isNull) {
predicates.add(builder.isNull(root.get(attributeName)));
} else {
predicates.add(builder.isNotNull(root.get(attributeName)));
}
predicates.add(QueryByExamplePredicateBuilder.getPredicate(root, builder, example));
return builder.and(predicates.toArray(new Predicate[0]));
};
}
And use it:
Example example = Example.of(
user,
ExampleMatcher.matching()
.withMatcher("name", contains().ignoreCase())
);
repository.findAll(specificationAttributeNull(true, example, "phoneNumber"));