如何在spring boot中注册jpa转换器？

Question

I've an entity called Lawyer and the following piece of code in a LawyerRepository :

import javaslang.control.Option;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.query.Param;
import org.springframework.stereotype.Repository;

@Repository
public interface LawyerRepository extends JpaRepository<Lawyer, Long> {

    @Query("select distinct l from Lawyer l where l.account.username = :email")
    Option<Lawyer> findLawyerByEmail(@Param("email") String email);

}

As you can see I'd like to return javaslang.control.Option instead of java.util.Optional . It results in the following exception:

org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.util.ArrayList] to type [javaslang.control.Option] for value '[lawyer.Lawyer@5e4c0db5]'; nested exception is org.springframework.core.convert.ConverterNotFoundException: No converter found capable of converting from type [java.util.ArrayList] to type [javaslang.control.Option]

And here's the converter:

import javaslang.control.Option;
import org.springframework.core.convert.converter.Converter;
import org.springframework.stereotype.Component;

import java.util.ArrayList;

@Component
public class OptionConverter implements Converter<ArrayList<?>, Option<?>> {

    @Override
    public Option<?> convert(ArrayList<?> input) {
        if (true) {
            throw new RuntimeException("lol");
        }
        return null;
    }

}

My question is how to register the converter I provided properly?

Answer 1

Seems Spring's converter(springframework.core.convert.converter.Converter) doesn't work with JPA.

U may have to use JPA Attribute Converter: http://www.thoughts-on-java.org/jpa-21-type-converter-better-way-to/ .

It's good that Spring can make Spring's converter work with JPA, so it would be consistent as other spring-data-* projects.