Category: java
get user list from DB and return response
Published on 20 Apr 2026
Explanation
Define a User entity mapped to the
database table using JPA annotations.
Code:
@Entity
@Table(name = "users")
public class User {
@Id
@GeneratedValue(strategy =
GenerationType.IDENTITY)
private Long id;
private String name;
private String email;
// getters and setters
}
Explanation
Create a repository interface extending
JpaRepository to
fetch user records from the database.
Code:
import org.springframework.data.jpa.
repository.JpaRepository;
public interface UserRepository extends
JpaRepository<User, Long> {
}
Explanation
Service layer contains business logic
and calls
repository methods like findAll().
Code:
@Service
public class UserService {
private final UserRepository
userRepository;
public UserService(UserRepository
userRepository) {
this.userRepository =
userRepository;
}
public List<User> getAllUsers() {
return userRepository.findAll();
}
}
Explanation
Expose REST API endpoint to return the
list of users as JSON response.
Code:
@RestController
@RequestMapping("/api/users")
public class UserController {
private final UserService userService;
public UserController(UserService
userService) {
this.userService = userService;
}
@GetMapping
public List<User> getUsers() {
return userService.getAllUsers();
}
}
Explanation
Example JSON response returned when
calling GET
/api/users endpoint.
Code:
[
{
"id": 1,
"name": "hackforge",
"email": "hackforge@gmail.com"
},
{
"id": 2,
"name": "academy",
"email": "academy@gmail.com"
}
]