[转]hibernate 集合类(Collections)照射(二)- List

[转]hibernate 集合类(Collections)映射(二)- List

二、List集合映射

 

1. 实体类:

 

实体类还是采用DepartmentEmployee,详见我写的多对一(many-to-one)文章,在它们的基础上进行修改如下所示:

 

将原Department实体类中的Set替换成List,如下所示:

 

Java代码

package com.reiyen.hibernate.domain;  

 

public class Department {  

 

    private int id;  

    private String name;  

    private List<Employee> emps;  

       //SetterGetter方法  

} 

 

package com.reiyen.hibernate.domain;

 

public class Department {

 

    private int id;

    private String name;

    private List<Employee> emps;

       //SetterGetter方法

}在原Employee实体类中增加了重写的toString()方法,方法如下:

 

Java代码

@Override 

    public String toString() {  

        return "id=" + this.id + " name=" + this.name;  

    } 

 

@Override

    public String toString() {

       return "id=" + this.id + " name=" + this.name;

    } 2. 配置文件:

 

修改Department.hbm.xml配置文件,其它的还是保持以前的不变,修改的Department.hbm.xml配置文件如下:

 

Xml代码

<?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.reiyen.hibernate.domain"> 

    <class name="Department" > 

        <id name="id" > 

            <generator class="native" /> 

        </id> 

        <property name="name" /> 

        <!--    

        <set name="emps"> 

        <key column="depart_id" /> 

        <one-to-many class="Employee"/> 

        </set>--> 

        <list name="emps"> 

        <key column="depart_id" /> 

        <!-- list-index:用来记录加入list集合的元素的顺序 ,会一定程度影响性能,所以可以使用bag替代list--> 

        <list-index column="order_col" /> 

        <one-to-many class="Employee"/> 

        </list> 

    </class> 

</hibernate-mapping> 

 

<?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.reiyen.hibernate.domain">

    <class name="Department" >

       <id name="id" >

           <generator class="native" />

       </id>

       <property name="name" />

       <!-- 

       <set name="emps">

       <key column="depart_id" />

       <one-to-many class="Employee"/>

       </set>-->

       <list name="emps">

       <key column="depart_id" />

       <!-- list-index:用来记录加入list集合的元素的顺序 ,会一定程度影响性能,所以可以使用bag替代list-->

       <list-index column="order_col" />

       <one-to-many class="Employee"/>

       </list>

    </class>

</hibernate-mapping> 3.测试类(只是对many-to-one中的测试类进行了少量的修改),如下所示: