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.

CustomerRepository.java

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.

CustomerRepositoryCustomAbc.java

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.

CustomerRepositoryImpl.java

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.

CustomerRepository.java

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

DomainRepository.java

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.

DomainRepositoryCustomAnyName.java

package com.mkyong.domain;

public interface DomainRepositoryCustomAnyName {

    int updateDomainDisplayFlagOnly(String domain, boolean flag);

}

2.3 Custom implementation.

DomainRepositoryImpl.java

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

DomainRepository.java

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