我是新来的春靴。我有一个mysql数据库，我使用一个查询来计算表中的行数。但它不工作，它仍然返回我的原始表数据。你能帮我查一下密码吗。
这是我的实体：

@Entity
@Table(name = "act_id_membership", schema = "activiti", catalog = "")
@IdClass(ActIdMembershipEntityPK.class)
public class ActIdMembershipEntity {
    private String userId;
    private String groupId;

    @Id
    @Column(name = "USER_ID_")
    public String getUserId() {
        return userId;
    }

    public void setUserId(String userId) {
        this.userId = userId;
    }

    @Id
    @Column(name = "GROUP_ID_")
    public String getGroupId() {
        return groupId;
    }

    public void setGroupId(String groupId) {
        this.groupId = groupId;
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        ActIdMembershipEntity that = (ActIdMembershipEntity) o;
        return Objects.equals(userId, that.userId) &&
                Objects.equals(groupId, that.groupId);
    }

    @Override
    public int hashCode() {
        return Objects.hash(userId, groupId);
    }
}

我的问题是：

@Repository
public interface MemershipRepository extends JpaRepository<ActIdMembershipEntity, String> {
    @Query ("select new com.example.activiti_restful.dtos.UserMembership(i.userId, count(i)) from ActIdMembershipEntity i where i.userId ='kermit'")
    UserMembership countMemberships(String userId);
}

更新代码：我的服务类：

@Service
public class MembershipService {
@Autowired
private MemershipRepository repository;

public long count() {
    return repository.count();
}

我的资源类：

@RestController
public class MembershipResource {
@Autowired
private MembershipService membershipService;

@GetMapping("/membership")
public long list() {return membershipService.count();}
}

我的自定义json对象类：

public class UserMembership {
    private String userId;

    private long numberOfusers;

    public UserMembership(String userId, long numberOfusers) {
        this.userId = userId;
        this.numberOfusers = numberOfusers;
    }
}

mysql表：act\u id\u成员