一对多的单向练习
group方做为一的一方
user方作为多的一方
Group的类描述:
package com.anryn;
import java.util.HashSet;
import java.util.Set;
public class Group {
private int id ;
private String address ;
private Set<User> users = new HashSet<User>() ;
public Group() {
}
public Set<User> getUsers() {
return users;
}
public void setUsers(Set<User> users) {
this.users = users;
}
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
}
而对于group.hbm.xml的文件描写如下:
<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping package="com.anryn">
<class name="Group" table="t_Group">
<id name="id">
<generator class="native"/>
</id>
<property name="address"/>
<set name="users">
<key column="groupId"></key>
<one-to-many class="com.anryn.User"/>
</set>
</class>
</hibernate-mapping>
user类中只有几个一般属性
通过测试代码可知:最终生成了两张表,产生了一个外键,groupId做为user的一个外键和group相关联。
package com.anryn;
import java.util.Date;
import org.hibernate.cfg.AnnotationConfiguration;
import org.hibernate.tool.hbm2ddl.SchemaExport;
import org.junit.Test;
public class HibernateXMLTest {
@Test
public void testSchemaExport() {
new SchemaExport(new AnnotationConfiguration().configure()).create(false, true) ;
}
}
分享到:
评论