Spring Data Add custom method to Repository

In this article, we will show you how to add a custom method to Spring Data JPA CrudRepository and MongoDB MongoRepository

1. CrudRepository

1.1 Review a CustomerRepository, we will add a custom method to this repository.

package com.mkyong.dao;
import com.mkyong.model.Customer;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.query.Param;
import java.util.Date;
import java.util.List;
import java.util.stream.Stream;
public interface CustomerRepository extends CrudRepository<Customer, Long> {
    List<Customer> findByEmail(String email);
    @Query("select c from Customer c where c.email = :email")
    Stream<Customer> findByEmailReturnStream(@Param("email") String email);
	// I have a complicated logic, no idea how to implement with @Query ...

1.2 Create an interface.

package com.mkyong.dao;
import com.mkyong.model.Customer;
import java.util.List;
public interface CustomerRepositoryCustomAbc {
    List<Customer> findByAVeryComplicatedQuery(Long id, String name, String address);

1.3 For implementation class, the class name is very strict, you need to follow the “core repository interface + Impl” pattern. Failed to follow this pattern will cause the “Spring property unable to find” error message.

package com.mkyong.dao;
import com.mkyong.model.Customer;
import java.util.List;
public class CustomerRepositoryImpl implements CustomerRepositoryCustomAbc {
    @Override
    public List<Customer> findByAVeryComplicatedQuery(Long id, String name, String address) {
        //...

1.4 Update CustomerRepository to extend the new CustomerRepositoryCustomAbc interface.

package com.mkyong.dao;
import com.mkyong.model.Customer;
import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.CrudRepository;
import org.springframework.data.repository.query.Param;
import java.util.Date;
import java.util.List;
import java.util.stream.Stream;
public interface CustomerRepository extends CrudRepository<Customer, Long>, CustomerRepositoryCustomAbc{
   //...

Done.

2. MongoRepository

2.1 Another example to add a new “update a particular field” method to MongoRepository

package com.mkyong.domain;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.data.mongodb.repository.Query;
import java.util.List;
public interface DomainRepository extends MongoRepository<Domain, Long> {
    Domain findByDomainAndIP(String domain, String ip);
    @Query("{domain: { $regex: ?0 } })")
    List<Domain> findCustomByRegExDomain(String domain);
	//how to update a particular field? save() is not what I want.

2.2 Custome interface.

package com.mkyong.domain;
public interface DomainRepositoryCustomAnyName {
    int updateDomainDisplayFlagOnly(String domain, boolean flag);

2.3 Custom implementation.

package com.mkyong.domain;
import com.mongodb.WriteResult;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.mongodb.core.MongoTemplate;
import org.springframework.data.mongodb.core.query.Criteria;
import org.springframework.data.mongodb.core.query.Query;
import org.springframework.data.mongodb.core.query.Update;
//Impl postfix of the name on it compared to the core repository interface
public class DomainRepositoryImpl implements DomainRepositoryCustomAnyName {
    @Autowired
    MongoTemplate mongoTemplate;
    @Override
    public int updateDomainDisplayFlagOnly(String domain, boolean flag) {
        Query query = new Query(Criteria.where("domain").is(domain));
        Update update = new Update();
        update.set("display", flag);
        WriteResult result = mongoTemplate.updateFirst(query, update, Domain.class);
        if(result!=null)
            return result.getN();
        else
            return 0;

2.4 Update DomainRepository to extend the new custom interface – DomainRepositoryCustomAnyName

package com.mkyong.domain;
import org.springframework.data.mongodb.repository.MongoRepository;
import org.springframework.data.mongodb.repository.Query;
import java.util.List;
public interface DomainRepository extends MongoRepository<Domain, Long>, DomainRepositoryCustomAnyName {
    //...

Done.

References

1. Spring Data – Custom implementations
2. Spring Boot – Spring Data MongoDB Example