Hibernate关联映射—组件映射

组件映射(User-Name)

关联属性是个复杂类型的持久化类，但不是实体既：数据库中没有表与该属性对应，但该类的属性要持久保存。

•<component name="name" class="Name">
•<property name="firstName" column="first_name"/>
•<property name="middleName" column="middle_name"/>
•<property name="lastName" column="last_name"/>
•</component>
当组件映射的属性不能和表中的字段简单对应的时候可以选择实现：

org.hibenrate.usertype.UserType或org.hibernate.usertype.CompositeUserType

1、首先创建domain类：

package com.zhaosoft.domain;

import java.util.Date;

public class User {

private int id;

private Name name;

private Date birthday;

private int ver; //版本号，悲观锁

public int getVer() {

return ver;

}

public void setVer(int ver) {

this.ver = ver;

}

public int getId() {

return id;

}

public void setId(int id) {

this.id = id;

}

public Date getBirthday() {

return birthday;

}

public void setBirthday(Date birthday) {

this.birthday = birthday;

}

public Name getName() {

return name;

}

public void setName(Name name) {

this.name = name;

}

}

2、实现组件映射对应的类：

package com.zhaosoft.domain;

public class Name {

private String firstName;

private String middleName;

private String lastName;

public String getMiddleName() {

return middleName;

}

public void setMiddleName(String middleName) {

this.middleName = middleName;

}

public String getFirstName() {

return firstName;

}

public void setFirstName(String firstName) {

this.firstName = firstName;

}

public String getLastName() {

return lastName;

}

public void setLastName(String lastName) {

this.lastName = lastName;

}

}

3、映射关系：

<?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.zhaosoft.domain">

<!-- 当discriminator-value值为0时，为普通员工 -->

<class name="User">

<cache usage="read-only"/>

<id name="id">

<!-- 表示主键为自动增长 -->

<generator class="hilo"/>

</id>

<!--版本号-->

<version name="ver"/>

<property name="birthday" type="date"/>

<!-- 组件映射 -->

<component name="name" class="Name">

<property name="firstName" column="first_name"/>

<property name="middleName" column="middle_name"/>

<property name="lastName" column="last_name"/>

</component>

</class>

<query name="getUserByID">

<![CDATA[from User ]]>

</query>

</hibernate-mapping>