hibernate 映射 組件映射

應用場景：

     從對象建模的角度來看，如果兩個對象之間是一種聚集——是整體的一部分（part-of）的關係，聚集是一種強健的關聯形式：它對於對象的生命週期有一些額外的語義。在這種情況下，我們有一種更強健的形式：複合（composition），在這裏部分的生命週期完全依賴於整體的生命週期。對象建模專家和UML設計師聲稱，就實際的java實現而言，在這個複合和其他更弱形式的關聯之間是沒有區分的。但是在ORM的上下文種，則有一個很大德區別：複合的關係經常是一個備選的值類型。

示例實體：

      User Address一個 User有一個家庭地址（homeAddress）和一個賬單地址（billingAddress）。User是實體，而Address是值類型。他們是聚集關係。

一、XML的實現

package com.ccay.test.componentMapping_xml;

public class User {
	private long userId;
	private String firstname;
	private String lastname;
	private Address homeAddress;
	private Address billingAddress;
	
	public Address getHomeAddress() {
		return homeAddress;
	}
	public void setHomeAddress(Address homeAddress) {
		this.homeAddress = homeAddress;
	}
	public Address getBillingAddress() {
		return billingAddress;
	}
	public void setBillingAddress(Address billingAddress) {
		this.billingAddress = billingAddress;
	}

	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;
	}
	public long getUserId() {
		return userId;
	}
	public void setUserId(long userId) {
		this.userId = userId;
	}
}

package com.ccay.test.componentMapping_xml;

public class Address {
	private User user;
	private String street;
	private String zipcode
	private String city;
	public User getUser() {
		return user;
	}
	public void setUser(User user) {
		this.user = user;
	}
	public String getStreet() {
		return street;
	}
	public void setStreet(String street) {
		this.street = street;
	}
	public String getZipcode() {
		return zipcode;
	}
	public void setZipcode(String zipcode) {
		this.zipcode = zipcode;
	}
	public String getCity() {
		return city;
	}
	public void setCity(String city) {
		this.city = city;
	}
}

package com.ccay.test.componentMapping_xml;

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

import com.ccay.test.HibernateSessionFactory;

public class Test {
	@org.junit.Test
	public void testDDL(){
		Session session = HibernateSessionFactory.getSession();
		Transaction transaction = session.beginTransaction();
		
		Address homeAddress = new Address();
		homeAddress.setCity("china");
		homeAddress.setStreet("zhongshan");
		homeAddress.setZipcode("010");
		
		Address billingAddress = new Address();
		billingAddress.setCity("china");
		billingAddress.setStreet("zhongshan2");
		billingAddress.setZipcode("0102");
		
		User user= new User();
		user.setFirstname("firstName");
		user.setLastname("lastName");
		user.setHomeAddress(homeAddress);
		user.setBillingAddress(billingAddress);
		session.save(user);
		transaction.commit();
		HibernateSessionFactory.closeSession();
	}
}

HBM.XML映射文件

<?xml version="1.0" encoding="utf-8"?>
<!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.ccay.test.componentMapping_xml.User" table="COM_MAP_USER" >
        <id name="userId" type="long">
            <column name="USER_ID"/>
            <generator class="native" />
        </id>
        <property name="firstname" type="string">
            <column name="FIRSTNAME" length="40" />
        </property>
        <property name="lastname" type="string">
            <column name="LASTNAME" length="50" />
        </property>
        <component name="homeAddress" class="com.ccay.test.componentMapping_xml.Address">
        	<!-- 可加入後退指針 -->
         <parent name="user"/>
        	<property name="street" type="string" column="HOME_STREET" not-null="true"/>
        	<property name="city" type="string" column="HOME_CITY" not-null="true"/>
        	<property name="zipcode" type="string" column="HOME_ZIPCODE" not-null="true"/>
        </component>
         <component name="billingAddress" class="com.ccay.test.componentMapping_xml.Address">
         	<parent name="user"/>
        	<property name="street" type="string" column="BILLING_STREET" not-null="true"/>
        	<property name="city" type="string" column="BILLING_CITY" not-null="true"/>
        	<property name="zipcode" type="string" column="BILLING_ZIPCODE" not-null="true"/>
        </component>
    </class>
</hibernate-mapping>

hibernate自動 DDL

    create table COM_MAP_USER (
        USER_ID bigint not null auto_increment,
        FIRSTNAME varchar(40),
        LASTNAME varchar(50),
        HOME_STREET varchar(255) not null,
        HOME_CITY varchar(255) not null,
        HOME_ZIPCODE varchar(255) not null,
        BILLING_STREET varchar(255) not null,
        BILLING_CITY varchar(255) not null,
        BILLING_ZIPCODE varchar(255) not null,
        primary key (USER_ID)
    )

powerDesigner 逆向工程如圖

二、註解的實現

package com.ccay.test.componentMapping_JAPAnnotation;

import javax.annotation.Generated;
import javax.persistence.AttributeOverride;
import javax.persistence.AttributeOverrides;
import javax.persistence.Column;
import javax.persistence.Embedded;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

@Entity
@Table(name = "COM_MAP_USER")
public class User {
	@Id
	@GeneratedValue
	private long userId;
	private String firstname;
	private String lastname;
	@Embedded
	@AttributeOverrides({//可以覆蓋屬性值，重命名列名
		@AttributeOverride(name="street",column = @Column(name="HOME_STREET")),
		@AttributeOverride(name="zipcode",column = @Column(name="HOME_ZIPCODE")),
		@AttributeOverride(name="city",column = @Column(name="HOME_CITY"))
	})
	private Address homeAddress;
	@Embedded
	private Address billingAddress;
	
	public Address getHomeAddress() {
		return homeAddress;
	}
	public void setHomeAddress(Address homeAddress) {
		this.homeAddress = homeAddress;
	}
	public Address getBillingAddress() {
		return billingAddress;
	}
	public void setBillingAddress(Address billingAddress) {
		this.billingAddress = billingAddress;
	}

	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;
	}
	public long getUserId() {
		return userId;
	}
	public void setUserId(long userId) {
		this.userId = userId;
	}
}

 

package com.ccay.test.componentMapping_JAPAnnotation;

import javax.persistence.Column;
import javax.persistence.Embeddable;

import org.hibernate.annotations.Parent;

@Embeddable
public class Address {
	@Parent//JPA中沒有 所以用 org.hibernate.annotations.Parent
	private User user;
	@Column(name="ADDRESS_STREET",nullable=false)
	private String street;
	@Column(name="ADDRESS_ZIPCODE",nullable=false)
	private String zipcode;
	@Column(name="ADDRESS_CITY",nullable=false)
	private String city;
	
	public User getUser() {
		return user;
	}
	public void setUser(User user) {
		this.user = user;
	}
	public String getStreet() {
		return street;
	}
	public void setStreet(String street) {
		this.street = street;
	}
	public String getZipcode() {
		return zipcode;
	}
	public void setZipcode(String zipcode) {
		this.zipcode = zipcode;
	}
	public String getCity() {
		return city;
	}
	public void setCity(String city) {
		this.city = city;
	}
}

hibernate 自動DDL

    create table COM_MAP_USER (
        userId bigint not null auto_increment,
        ADDRESS_CITY varchar(255) not null,
        ADDRESS_STREET varchar(255) not null,
        ADDRESS_ZIPCODE varchar(255) not null,
        firstname varchar(255),
        HOME_CITY varchar(255),
        HOME_STREET varchar(255),
        HOME_ZIPCODE varchar(255),
        lastname varchar(255),
        primary key (userId)
    )

逆向工程