Hibernate映射Set

         Hibernate映射Set

        一 POJO

     package example.start.set;

import java.util.HashSet;
import java.util.Set;

public class Person
{
 private int id;
 private String name;
 private int age;
 private Set classes = new HashSet();  
  
 public Person()
 {
 }

 public int getId()
 {
  return id;
 }

 public void setId(int id)
 {
  this.id = id;
 }

 public String getName()
 {
  return name;
 }

 public void setName(String name)
 {
  this.name = name;
 }

 public int getAge()
 {
  return age;
 }

 public void setAge(int age)
 {
  this.age = age;
 }

 public Set getClasses()
 {
  return classes;
 }

 public void setClasses(Set classes)
 {
  this.classes = classes;
 }
}
           二 映射文件

         <?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>
    <class name="example.start.set.Person" table="person">
        <id name="id" column="classid">
            <generator class="identity"/>
        </id>
        <property name="name" type="string">
            <column name="name"/>
        </property>
        <property name="age" type="integer">
            <column name="age" />
        </property>
           
       <set name="classes" table="class">
         <key column="classid" not-null="true"/>
         <element type="string" column="class_name" not-null="true"/>
       </set>
    </class>
</hibernate-mapping>

 

        三 测试类

     package example.start.set;
import java.util.HashSet;
import java.util.Set;

import org.hibernate.Session;
import org.hibernate.Transaction;

import com.HibernateSessionFactory;

public class CreateAndStorePerson
{
 
 public static void main(String[] args)
 {
  Session session = HibernateSessionFactory.getSession();
  Transaction tx = session.beginTransaction();
  
  Person yeeku = new Person();
  yeeku.setAge(22);
  yeeku.setName("哈哈Set"); 
  
  Set s = new HashSet();
  s.add("数据结构"); 
  s.add("操作系统");
    
  yeeku.setClasses(s);
    
  session.save(yeeku);
  tx.commit();
  HibernateSessionFactory.closeSession();
  
 }

}
与List类似，但是它是没有顺序的，不需要index key