Spring Boot，如何对桥表的多对多关系进行条件查询？

Question

我有三个实体包括桥实体：

团队实体：

       public class Team {
        
            @Id
            @GeneratedValue(strategy = GenerationType.IDENTITY)
            @Column(name = "TEAM_ID")
            private Integer id;
        
            @Column(name = "teamname", length = 128, nullable = false, unique = true)
            private String teamname;
            @Column(name = "delete_date", length = 128, nullable = true)
            private Date delete_date;
        
            @Column(name = "description", nullable = true, length = 240)
            private String description;
        
            @Column(name = "active", length = 64, nullable = false)
            private int active;
            @OneToMany(mappedBy = "team", fetch = FetchType.LAZY)
            private Set<TeamUsers> team_users = new HashSet<TeamUsers>();

---getter setter constructur
    }

用户实体：

   @Entity
    @Table(name = "tblUsers")
    public class User {
    
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private Integer id;
        @Column(name = "Username", length = 128, nullable = false, unique = true)
        private String username;
        @Column(name = "FirstName", nullable = false, length = 45)
        private String firstName;
        @Column(name = "LastName", nullable = false, length = 45)
        private String lastName;
        @Column(name = "Password", length = 64, nullable = false)
        private String password;
        @Column(name = "Email", length = 128, nullable = false, unique = true)
        private String email;
        @Column(name = "Phone", length = 64, nullable = false, unique = true)
        private String phoneNumber;
    
    
        @OneToMany(mappedBy = "user", fetch = FetchType.LAZY)
    
        private Set<TeamUsers> team_users = new HashSet<TeamUsers>();

---getter setter constructur

    }

TeamUsers - 具有额外列的桥接实体（活动）：

@Entity
@Table(name = "team_users")

public class TeamUsers implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Integer id;

    @ManyToOne(fetch = FetchType.LAZY, optional = false, cascade = CascadeType.ALL)
    @JoinColumn(name = "TEAM_ID")
    private Team team;

    @ManyToOne(fetch = FetchType.LAZY, optional = false, cascade = CascadeType.ALL)
    @JoinColumn(name = "USER_ID")
    private User user;

    @Column(name = "active")
    private Integer active;

---getter setter constructur
}

在团队存储库中我有代码：

package com.crmbackend.allService.teamService.repo;

import java.util.List;

import org.springframework.data.jpa.repository.Query;
import org.springframework.data.repository.PagingAndSortingRepository;

import com.crmbackend.entity.Team;

public interface TeamRepository extends PagingAndSortingRepository<Team, Integer> {

    @Query("select t from Team t")
    public List<Team> getAllTeamAndDetails();

}

如果我在 Junit Test 中调用 getAllTeamAndDetails() 方法，结果是所有团队信息： 它基本上告诉我我有多少个团队，以及团队用户反对谁属于哪个团队。

现在，我的问题是我想获取所有团队信息和团队用户信息， 但在桥接表中只有它们的 active = 1。

这意味着如果团队用户记录的活动 = 0，则该用户不应显示在结果中。

这个查询应该是什么样子或者最好的方法是什么？

谢谢

Answer 1

这对于可用的普通 JPA/Hibernate 或 Spring Data JPA 工具是不可能的。为此，您必须使用 DTO。我认为这是Blaze-Persistence Entity Views 的完美用例。

我创建了该库以允许在 JPA 模型和自定义接口或抽象类定义模型之间轻松映射，例如 Spring Data Projections on steroids。这个想法是您按照自己喜欢的方式定义目标结构（域模型），并通过 JPQL 表达式将属性（getter）映射到实体模型。

使用 Blaze-Persistence Entity-Views 的用例的 DTO 模型可能如下所示：

@EntityView(Team.class)
public interface TeamDto {
    @IdMapping
    Integer getId();
    String getDescription();
    @Mapping("team_users[active = 1].user")
    Set<UserDto> getUsers();

    @EntityView(User.class)
    interface UserDto {
        @IdMapping
        Integer getId();
        String getUsername();
    }
}

查询是将实体视图应用于查询的问题，最简单的就是通过 id 进行查询。

TeamDto a = entityViewManager.find(entityManager, TeamDto.class, id);

Spring Data 集成让您可以像使用 Spring Data Projections 一样使用它：https://persistence.blazebit.com/documentation/entity-view/manual/en_US/index.html#spring-data-features

Page<TeamDto> findAll(Pageable pageable);

最好的部分是，它只会获取实际需要的状态！