spring jpa: using Example to filter date as string-CodePudding

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 ?

CodePudding user response：

The short answer is, you don't.

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

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.