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Looking to fetch entities with null fields using Spring Data JPA? Whether you need all such entities or just the first one, it’s super clean with method naming conventions.

📌 1. Fetch All Where Field Is null

Suppose you have a User entity with an email field, and you want all users where email is null.

🧱 Entity Class

java

import javax.persistence.*;

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private String email;

    // Getters and Setters
}

📚 Repository Interface

java

import org.springframework.data.jpa.repository.JpaRepository;
import java.util.List;

public interface UserRepository extends JpaRepository<User, Long> {
    List<User> findAllByEmailIsNull();
}

🔧 Service Example

java

@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;

    public List<User> getUsersWithNullEmail() {
        return userRepository.findAllByEmailIsNull();
    }
}

🌐 Controller Example

java

@RestController
@RequestMapping("/api/users")
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping("/null-email")
    public List<User> getUsersWithNullEmail() {
        return userService.getUsersWithNullEmail();
    }
}

🎯 2. Fetch Just One (First Match)

Use findFirstBy...IsNull() for one result.

📚 Repository Interface

java

import java.util.Optional;

public interface UserRepository extends JpaRepository<User, Long> {
    Optional<User> findFirstByEmailIsNull();
}

🔧 Service

java

@Service
public class UserService {
    @Autowired
    private UserRepository userRepository;

    public Optional<User> getFirstUserWithNullEmail() {
        return userRepository.findFirstByEmailIsNull();
    }
}

🌐 Controller

java

@RestController
@RequestMapping("/api/users")
public class UserController {
    @Autowired
    private UserService userService;

    @GetMapping("/first-null-email")
    public Optional<User> getFirstUserWithNullEmail() {
        return userService.getFirstUserWithNullEmail();
    }
}

📝 Summary

GoalMethod NameReturn TypeGet all where field is nullfindAllBy<Field>IsNull()List<T>Get one where field is nullfindFirstBy<Field>IsNull()Optional<T>

With Spring Data JPA’s query method naming, null checks are easy—no need to write JPQL manually.