@Data @AllArgsConstructor @NoArgsConstructor @Builder @Table(name = "advert") public class Advert { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @ApiModelProperty(value = "广告唯一id") private Integer id; @ApiModelProperty(value = "广告名称") @NotBlank(message = "广告名称不可为空", groups = {AddGroup.class, UpdateGroup.class}) private String name; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "position_id") private AdPosition position; @ManyToOne(fetch = FetchType.LAZY) @JoinColumn(name = "media_id") private MediaFile media; } @Data @AllArgsConstructor @NoArgsConstructor @Builder @Table(name = "ad_position") public class AdPosition { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer id; @ApiModelProperty(value = "位置名称") @NotBlank(message = "位置名称不可为空", groups = {AddGroup.class}) private String name; @OneToMany(mappedBy = "AdPosition", cascade = CascadeType.ALL) private List<Advert> adverts = new ArrayList<>(); } @Data @AllArgsConstructor @NoArgsConstructor @Builder @Table(name = "media_file") public class MediaFile { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Integer id; @ApiModelProperty(value = "媒体文件名称") private String fileName; @ApiModelProperty(value = "媒体文件类型") private Integer fileType; @ApiModelProperty(value = "媒体文件URL地址") private String fileUrl; @OneToMany(mappedBy = "MediaFile", cascade = CascadeType.ALL) private List<Advert> adverts = new ArrayList<>(); } public interface MyBaseMapper<T> extends Mapper<T>, MySqlMapper<T>,MyInsertListMapper<T> {} public interface AdvertMapper extends MyBaseMapper<Advert> {}如何在查询Advert表数据时，将关联的ad_position和media_file表中的数据一并查询

可以使用MyBatis的XML配置文件实现关联查询。以下是一个简单的示例，假设我们要查询Advert表中的数据，并将关联的AdPosition和MediaFile表中的数据一并查询出来。

首先，在AdvertMapper.xml中定义一个查询语句，使用左连接将Advert表和AdPosition表、MediaFile表关联起来，并使用resultMap将查询结果映射到Advert对象中：

<select id="findAdverts" resultMap="advertMap">
    SELECT a.*, p.id AS position_id, p.name AS position_name, m.id AS media_id, m.file_name, m.file_type, m.file_url
    FROM advert a
    LEFT JOIN ad_position p ON a.position_id = p.id
    LEFT JOIN media_file m ON a.media_id = m.id
</select>

<resultMap id="advertMap" type="Advert">
    <id property="id" column="id"/>
    <result property="name" column="name"/>
    <association property="position" javaType="AdPosition">
        <id property="id" column="position_id"/>
        <result property="name" column="position_name"/>
    </association>
    <association property="media" javaType="MediaFile">
        <id property="id" column="media_id"/>
        <result property="fileName" column="file_name"/>
        <result property="fileType" column="file_type"/>
        <result property="fileUrl" column="file_url"/>
    </association>
</resultMap>

接下来，在AdvertMapper接口中定义一个findAdverts方法，用于调用上面定义的查询语句：

List<Advert> findAdverts();

最后，在需要使用的地方调用findAdverts方法即可查询出Advert表中的数据，并将关联的AdPosition和MediaFile表中的数据一并查询出来。