按条件动态搜索

我在用QueryDSL with Spring Data Jpa我想执行一些动态搜索。

我遵循这个Answer https://stackoverflow.com/a/23896303/3756879没关系BooleanBuilder但就我而言，我必须加入。

那么，如果我有 3 个连接，我该如何做到这一点player, player_team, team我有关于球员姓名和球队名称的可选参数吗？

 ________       ___________________       _______
| player |    | player_team         |    | team  |
|------  |    |----------------     |    |-------|
| id     |    | player_team_id (pk) |    | id    |
| name   |    | player_id (fk)      |    | name  |
  ------      | team_id (fk)        |     -------
                -----------      

播放器.java

@Entity
@Table(...)
public class Player implements java.io.Serializable {

    private Integer idPlayer ;
    private String namePlayer;
    private Set<PlayerTeam> player_teams = new HashSet<PlayerTeam>(0);  
    ...
}

团队.java

@Entity
@Table(...)
public class Team implements java.io.Serializable {

    private Integer idTeam ;
    private String nameTeam;
    private Set<PlayerTeam> player_teams = new HashSet<PlayerTeam>(0);  
    ...
}  

玩家团队.java

@Entity
@Table(...)
public class PlayerTeam implements java.io.Serializable {

    private Integer idPlayerTeam ;
    private Team team;
    private Player paleyr;
    ...
} 

对于每个域，我都有这样的存储库：

public interface PlayerRespository extends JpaRepository<Player, Integer>, QueryDslPredicateExecutor<Player> {

}

如果您不将额外的属性放入 PlayerTeam 中，则不应将其建模为实体。关于条件

player.namePlayer.eq(...)

and

new JPASubQuery().from(playerTeam)
    .where(playerTeam.player.eq(player), palyerTeam.team.name.eq(...))
    .exists()