Hibernate中ManyToOne,OneToMany,On

有3个表：
News：新闻表
NewsResource：新闻附件表
Resource：资源表

表关系：
1个新闻（News）对应多条新闻附件（NewsResource）
News：ID <---> NewsResource：news_id

1个新闻附件（NewsResource）对应1个资源（Resource）。
NewsResource：resource_id <---> Resource：ID

实体类如下：

@Entity  
@Table(name="news")  
public class NewsEntity implements Serializable{  
    private static final long serialVersionUID = 48L;  
  
    @Id   
    @GeneratedValue  
    @Column(name="ID")  
    private Long id;  
  
    @OneToMany(cascade=CascadeType.ALL,fetch=FetchType.LAZY,mappedBy="news")  
    private Set<NewsResourceEntity> newsResource;  
  
    //其他内容省略  
}  

NewsResource:
关于NewsResource表，有两种写法：
方法1：
这种写法用于不想和news表做级联更新，只想做级联查询的情况。news_id和resource_id都定义了2次，上面@Column用于自己表的更新，下面的@JoinColumn用于级联查询的时候的Join列。

@Entity  
@Table(name="newsresource")  
public class NewsResourceEntity implements Serializable{  
    private static final long serialVersionUID = 48L;  
  
    @Id  
    @GeneratedValue  
    @Column(name="ID")  
    private Long id;  
  
    @Column(name = "news_id")  
    private Long newsId;  
  
    @Column(name = "resource_id")  
    private Long resourceId;  
  
    @ManyToOne(cascade=CascadeType.ALL,fetch=FetchType.LAZY)  
    @JoinColumn(name="news_id", insertable = false,updatable = false)  
    private NewsEntity news;  
  
    @OneToOne(optional = false, cascade = CascadeType.MERGE)  
    @JoinColumn(name = "resource_id", referencedColumnName = "id", unique = true, insertable = false,updatable = false)  
    private ResourceEntity resource;  
  
    //其他内容省略  
}  

方法2：
这种写法就是典型的级联查询+级联更新。

@Entity  
@Table(name="newsresource")  
public class NewsResourceEntity implements Serializable{  
    private static final long serialVersionUID = 48L;  
  
    @Id   
    @GeneratedValue  
    @Column(name="ID")  
    private Long id;  
  
    @ManyToOne(cascade=CascadeType.ALL,fetch=FetchType.LAZY)  
    @JoinColumn(name="news_id")  
    private NewsEntity news;  
  
    @OneToOne(optional = false, cascade = CascadeType.MERGE)  
    @JoinColumn(name = "resource_id", referencedColumnName = "id", unique = true)  
    private ResourceEntity resource;  
  
        //其他内容省略  
}  

Resource：

@Entity  
@Table(name="resource")  
public class ResourceEntity implements Serializable {  
    private static final long serialVersionUID = 48L;  
  
    @Id   
    @GeneratedValue  
    @Column(name="ID")  
    private Long id;  
  
    @OneToOne(optional = true, cascade = CascadeType.ALL, fetch=FetchType.LAZY, mappedBy = "resource")  
    private NewsResourceEntity newsResource;  
  
        //其他内容省略  
}  

manyToOne 示例