component映射

component映射

在hibernate中,component是某个实体的逻辑组成部分，它与实体的根本区别是没有oid，
component可以成为是值对象（DDD）

采用component映射的好处：它实现了对象模型的细粒度划分，层次会更分明，复用率会更高

package com.bjsxt.hibernate;

public class Contact {
	
	private String email;
	
	private String address;
	
	private String zipCode;
	
	private String contactTel;

	public String getEmail() {
		return email;
	}

	public void setEmail(String email) {
		this.email = email;
	}

	public String getAddress() {
		return address;
	}

	public void setAddress(String address) {
		this.address = address;
	}

	public String getZipCode() {
		return zipCode;
	}

	public void setZipCode(String zipCode) {
		this.zipCode = zipCode;
	}

	public String getContactTel() {
		return contactTel;
	}

	public void setContactTel(String contactTel) {
		this.contactTel = contactTel;
	}
}

package com.bjsxt.hibernate;

public class User {
	
	private int id;
	
	private String name;
	
	private Contact contact; 
	
	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 Contact getContact() {
		return contact;
	}

	public void setContact(Contact contact) {
		this.contact = contact;
	}
	
}

<?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="com.bjsxt.hibernate.User" table="t_user">
		<id name="id">
			<generator class="native"/>
		</id>
		<property name="name"/>
		<component name="contact">
			<property name="email"/>
			<property name="address"/>
			<property name="zipCode"/>
			<property name="contactTel"/>
		</component>
	</class>
</hibernate-mapping>