hibernate annotation 继承关系映射

@Entity
@org.hibernate.annotations.Entity(polymorphism = PolymorphismType.IMPLICIT)
@Table(name = "article")
@Inheritance(strategy = InheritanceType.JOINED)
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
@NamedQueries( {
		@NamedQuery(name = "SelectAricle", query = "select new Aricle(id,title,subTitle,hits,addTime,tag) from Aricle"),
		@NamedQuery(name = "CountSelectAricle", query = "select count(*) from Aricle"),
		@NamedQuery(name = "findAriclebyId", query = "select new Aricle(id,title,subTitle,hits,addTime,tag) from Aricle where id=?"),
		@NamedQuery(name = "SelectAricleWithCategory", query = "select new Aricle(id,title,subTitle,hits,addTime,category) from Aricle aricle"),
		@NamedQuery(name = "SelectAricleWithCategoryId", query = "select new Aricle(id,title,subTitle,hits,addTime,category.id) from Aricle aricle")

})
public class Aricle extends IdEntity<Integer> {

	private static final long serialVersionUID = -8056490229900614401L;
	private String title;
	private String subTitle;
	private Date addTime;
	private Category category;
	private Set<BlogTags> blogTags = new LinkedHashSet<BlogTags>();
	private Integer hits;
	private String tag;//沉字段
	private Set<Comments> comments=new LinkedHashSet<Comments>();
	public String getTitle() {
		return title;
	}

	public Aricle() {
		super();
	}
	public Aricle(Integer id, String title, String subTitle){
		super.setId(id);
		this.title = title;
		this.subTitle = subTitle;
	}
	public Aricle(Integer id, String title, String subTitle, Integer hits, Date addTime,String tag) {
		super.setId(id);
		this.title = title;
		this.subTitle = subTitle;
		this.addTime = addTime;
		this.hits = hits;
		this.tag=tag;
	}

	public Aricle(Integer id, String title, String subTitle, Integer hits, Date addTime, Category category) {
		super.setId(id);
		this.title = title;
		this.subTitle = subTitle;
		this.addTime = addTime;
		this.category = category;
		this.hits = hits;
	}

	public Aricle(Integer id, String title, String subTitle, Integer hits, Date addTime, Integer categoryId) {
		super.setId(id);
		this.title = title;
		this.subTitle = subTitle;
		this.hits = hits;
		this.addTime = addTime;
		Category category = new Category();
		category.setId(categoryId);
		//category.setName(name);
		this.category = category;
	}

	public Aricle(Integer id, String title, String subTitle, Integer hits, Date addTime, Integer categoryId, String name) {
		super.setId(id);
		this.title = title;
		this.subTitle = subTitle;
		this.hits = hits;
		this.addTime = addTime;
		Category category = new Category();
		category.setId(categoryId);
		category.setName(name);
		this.category = category;
	}

	public Aricle(Integer id, String title, String subTitle, Integer hits, Date addTime, Integer categoryId,
			String name, Set<BlogTags> blogTags) {
		super.setId(id);
		this.title = title;
		this.subTitle = subTitle;
		this.hits = hits;
		this.addTime = addTime;
		Category category = new Category();
		category.setId(categoryId);
		category.setName(name);
		this.category = category;
		this.blogTags = blogTags;
	}

	public void setTitle(String title) {
		this.title = title;
	}

	@Column(nullable = true, columnDefinition = "varchar(145) default ''")
	public String getSubTitle() {
		return subTitle;
	}

	public void setSubTitle(String subTitle) {
		this.subTitle = subTitle;
	}

	@Temporal(TemporalType.TIMESTAMP)
	public Date getAddTime() {
		return addTime;
	}

	@Transient
	public String getAddTimeStr() {
		if (getAddTime() == null)
			return "";
		return DateFormatUtils.MIN_FORMAT.format(getAddTime());
	}

	@Transient
	public String getAddTimeYMD() {
		if (getAddTime() == null)
			return "";
		return DateFormatUtils.DATE_FORMAT.format(getAddTime());
	}

	@Transient
	public String getAddTimeMS() {
		if (getAddTime() == null)
			return "";
		return DateFormatUtils.format(getAddTime(), "HH:mm");
	}

	public void setAddTime(Date addTime) {
		this.addTime = addTime;
	}

	@ManyToOne(targetEntity = Category.class, cascade = { CascadeType.PERSIST, CascadeType.MERGE })
	@JoinColumn(name = "category_id", referencedColumnName = "id")
	@Fetch(FetchMode.SELECT)
	public Category getCategory() {
		return category;
	}

	public void setCategory(Category category) {
		this.category = category;
	}

	@Transient
	public String getCategoryName() {
		if (getCategory() == null)
			return "";
		return getCategory().getName();
	}

	@Transient
	/**从数据库中获取ID*/
	public Integer getCategoryId() {
		if (getCategory() == null)
			return null;
		return getCategory().getId();
	}

	@Transient
	public Integer getCategorysId() {
		if (category == null)
			return null;
		return category.getId();
	}

	@Column(insertable = false, updatable = false)
	public Integer getHits() {
		return hits;
	}

	public void setHits(Integer hits) {
		this.hits = hits;
	}

	@ManyToMany(fetch = FetchType.LAZY)
	@JoinTable(name = "tagsr_rlation", joinColumns = { @JoinColumn(name = "ArticlesID", referencedColumnName = "id") }, inverseJoinColumns = { @JoinColumn(name = "TagsID", referencedColumnName = "id") })
	//Fecth策略定义
	//集合按id排序.
	@OrderBy("nums desc")
	//集合中对象id的缓存.
	@Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
	@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
	public Set<BlogTags> getBlogTags() {
		return blogTags;
	}

	public void setBlogTags(Set<BlogTags> blogTags) {
		this.blogTags = blogTags;
	}

	@Override
	public int hashCode() {
		final int prime = 31;
		int result = 0;
		result = prime * result + ((title == null) ? 0 : title.hashCode());
		result += prime * getId();
		return result;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (!super.equals(obj))
			return false;
		if (getClass() != obj.getClass())
			return false;
		final Aricle other = (Aricle) obj;
		if (title == null) {
			if (other.title != null)
				return false;
		} else if (!title.equals(other.title))
			return false;
		if (getId() == null) {
			if (other.getId() != null)
				return false;
		} else if (!(getId() == other.getId()))
			return false;
		return true;
	}

	@Transient
	public String getTags() {
		StringBuffer sBuffer = new StringBuffer();
		for (Iterator<BlogTags> iterator = blogTags.iterator(); iterator.hasNext();) {
			sBuffer.append(iterator.next().getName()).append(",");
		}
		if (sBuffer.length() > 1)
			return sBuffer.substring(0, sBuffer.length() - 1);
		return null;
	}
	@Column(name="tags")
	public String getTag() {
		return tag;
	}

	public void setTag(String tag) {
		this.tag = tag;
	}
	@OneToMany(mappedBy = "aricle", fetch = FetchType.LAZY)
	@Cascade(org.hibernate.annotations.CascadeType.SAVE_UPDATE)
	@OrderBy("id desc")
	@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
	public Set<Comments> getComments() {
		return comments;
	}

	public void setComments(Set<Comments> comments) {
		this.comments = comments;
	}
	
}

 子类:

@Entity  
@Table(name = "article_data")
@PrimaryKeyJoinColumn(name="article_id",referencedColumnName="id")
//@DiscriminatorValue("article_data")   
public class AricleDetail  extends Aricle{
	/**
	 * 
	 */
	private static final long serialVersionUID = 2467125353876220860L;
	private String content;
	public String getContent() {
		return content;
	}
	public void setContent(String content) {
		this.content = content;
	}

}