请将上一个回答中的四张表的orm对象在springboot的项目中使用java注解演示出来

好的，以下是在 Spring Boot 项目中使用 Java 注解定义四张表的 ORM 对象示例：

1. 广告表 `advert` 的 ORM 对象：

@Entity
@Table(name = "advert")
public class Advert {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(name = "name")
    private String name;

    @Column(name = "start_date")
    private Date startDate;

    @Column(name = "end_date")
    private Date endDate;

    @Column(name = "link")
    private String link;

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

    @ManyToOne
    @JoinColumn(name = "position_id")
    private AdPosition position;

    @ManyToOne
    @JoinColumn(name = "media_id")
    private MediaFile mediaFile;

    // 省略 getter 和 setter 方法
}

2. 广告位置表 `ad_position` 的 ORM 对象：

@Entity
@Table(name = "ad_position")
public class AdPosition {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(name = "name")
    private String name;

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

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

    // 省略 getter 和 setter 方法
}

3. 广告媒体表 `media_file` 的 ORM 对象：

@Entity
@Table(name = "media_file")
public class MediaFile {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @Column(name = "name")
    private String name;

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

    @Column(name = "url")
    private String url;

    @Column(name = "create_time")
    private Date createTime;

    @Column(name = "update_time")
    private Date updateTime;

    // 省略 getter 和 setter 方法
}

4. 广告点击表 `advert_click` 的 ORM 对象：

@Entity
@Table(name = "advert_click")
public class AdvertClick {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    private Long id;

    @ManyToOne
    @JoinColumn(name = "advert_id")
    private Advert advert;

    @Column(name = "click_time")
    private Date clickTime;

    @Column(name = "click_ip")
    private String clickIp;

    // 省略 getter 和 setter 方法
}

这里使用了 `@Entity` 注解来标记实体类，`@Table` 注解来指定对应的数据库表名称，`@Id` 注解来标记主键字段，`@GeneratedValue` 注解用于指定主键生成策略，`@Column` 注解用于指定字段对应的数据库列名，`@ManyToOne` 注解用于指定多对一关联关系，`@JoinColumn` 注解用于指定外键列名。