如何使用Spring数据投影数组字段

@Entity
public class User {
    @Id
    private Long id;
    
    private String username;
    
    private String password;
    
    @ElementCollection
    private List<String> roles;
    
    // 省略构造方法、getter和setter
}

public interface UserProjection {
    @Value("#{target.roles}")
    List<String> getRoles();
}

public interface UserRepository extends JpaRepository<User, Long> {
    @Query("SELECT NEW com.example.UserProjection(u.roles) FROM User u WHERE u.username = :username")
    UserProjection findUserRolesByUsername(@Param("username") String username);
}

@Autowired
private UserRepository userRepository;

public List<String> getUserRoles(String username) {
    UserProjection userProjection = userRepository.findUserRolesByUsername(username);
    return userProjection.getRoles();
}