Spring Data JPA: Using Example to filter date as string

Question

Trying to test if a LocalDate contains a given year, day or month.

For example, given the criteria "1979", I'd like filter the rows returned by a findAll(Example<S> example) JPA query in such way that it will return any row containing "1979".

The "problem" is that the entity defines the date (let say a birth date) as a LocalDate and as such, doing:

ExampleMatcher personFilter = ExampleMatcher.matchingAll()
.withMatcher("birthDate", ExampleMatcher.GenericPropertyMatchers
.contains().ignoreCase());

personPage = repository.findAll(personFilter);

with PersonFilter#birthDate being itself a LocalDate.

Basically, I would have to have this entity to declare the birth date as a String for the filter to work, but that is not possible as the DB itself store it as a date.

Is there a way to solve such problem ? Like overriding the way the matching work ?

Answer 1

The short answer is, you don't.

For more advanced use cases and predicate definitions, have a look at the Querydsl support.

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The long answer is:

Query by Example (QBE) is a user-friendly querying technique with a simple interface. It allows dynamic query creation and does not require you to write queries that contain field names.

Query by Example is well suited for several use cases:

• Querying your data store with a set of static or dynamic constraints.
• Frequent refactoring of the domain objects without worrying about breaking existing queries.
• Working independently from the underlying data store API.

Query by Example also has several limitations:

• No support for nested or grouped property constraints, such as firstname = ?0 or (firstname = ?1 and lastname = ?2).
• Only supports starts/contains/ends/regex matching for strings and exact matching for other property types.