自身双向一对多关联其实是双向一对多（如Customer<----->Order）的特殊情况，以Category为例：
(1)Category类的类框图：
(2)CATEGORIES表的结构：
(3)持久化类Category：
package Bean;
import java.util.Set;
publicclassCategory {
private Longid;
private Stringname;
private CategoryparentCategory;
private Set<Category>childCategories;
public Category(Stringname,Category parent,Set<Category> childs) {
this.name=name;
this.parentCategory=parent;
this.childCategories=childs;
}
public CategorygetParentCategory() {
returnparentCategory;
}
publicvoidsetParentCategory(Category parentCategory) {
this.parentCategory =parentCategory;
}
public Set<Category>getChildCategories() {
returnchildCategories;
}
publicvoidsetChildCategories(Set<Category> childCategories) {
this.childCategories =childCategories;
}
public Long getId() {
returnid;
}
publicvoid setId(Long id) {
this.id = id;
}
public String getName() {
returnname;
}
publicvoid setName(String name) {
this.name = name;
}
}
(4)对象关系映射文件：Category.hbm.xml
<?xmlversion="1.0"encoding="UTF-8"?>
<!DOCTYPEhibernate-mapping
PUBLIC"-//Hibernate/HibernateMapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<classname="Bean.Category"table="categories">
<idname="id"type="long">
<generatorclass="increment"></generator>
</id>
<propertyname="name"column="name"type="string"></property>
<many-to-onename="parentCategory"column="category_id"cascade="all" class="Bean.Category"></many-to-one>
<setname="childCategories"cascade="all"inverse="true">
<keycolumn="category_id"></key>
<one-to-manyclass="Bean.Category"/>
</set>
</class>
</hibernate-mapping>
说明： <many-to-onename="parentCategory"column="category_id"cascade="all"class="Bean.Category">
</many-to-one>中的
column="category_id"指定表中的外键字段名，因为每个子Category只对应一个父Category，所以category_id的类型与所参照表的主
键的类型相同（此处即本表的id）。
(5)在主配置文件中加入映射文件Category.hbm.xml
<mapping
resource="Category.hbm.xml"/>
(6)级联保存Category对象：
package test;
import java.util.HashSet;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import Bean.Category;
public classTestCategory {
private static SessionFactoryfactory;
static {
factory =new Configuration().configure().buildSessionFactory();
}
public staticvoid main(String[] args) {
Session session = factory.openSession();
Transaction tx =
null;
try {
tx= session.beginTransaction();
Category category1=new Category("category1",null,newHashSet<Category>());
Category category2=new Category("category2", category1,new
HashSet<Category>());
Category category3=new Category("category3", category1,new
HashSet<Category>());
category1.getChildCategories().add(category2);
category1.getChildCategories().add(category3);
session.save(category1);
tx.commit();
}catch(Exception e) {
if (tx !=null)
tx.rollback();
e.printStackTrace();
}finally{
session.close();
}
}
}
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