Hibernate -- 映射组成关系

示例代码：

Address.java

package cn.itcast.compopent;

/**
 * 组件
 */
public class Address {
	
	private String street;
	private String city;
	private String province;
	private String zipcode;
	
	//表示Address所属的整体类
	private Customer customer;
	
	public Customer getCustomer() {
		return customer;
	}

	public void setCustomer(Customer customer) {
		this.customer = customer;
	}

	public Address() {
	}	
	
	public Address(String street, String city, String province, String zipcode) {
		this.street = street;
		this.city = city;
		this.province = province;
		this.zipcode = zipcode;
	}
	
	public String getStreet() {
		return street;
	}
	public void setStreet(String street) {
		this.street = street;
	}
	public String getCity() {
		return city;
	}
	public void setCity(String city) {
		this.city = city;
	}
	public String getProvince() {
		return province;
	}
	public void setProvince(String province) {
		this.province = province;
	}
	public String getZipcode() {
		return zipcode;
	}
	public void setZipcode(String zipcode) {
		this.zipcode = zipcode;
	}
}

Customer.java

package cn.itcast.compopent;

/**
 * 一的一端
 */
@SuppressWarnings("serial")
public class Customer implements java.io.Serializable {

	private Integer id;
	private String name;
	private Address homeAddress;
	private Address comAddress;

	public Address getHomeAddress() {
		return homeAddress;
	}

	public void setHomeAddress(Address homeAddress) {
		this.homeAddress = homeAddress;
	}

	public Address getComAddress() {
		return comAddress;
	}

	public void setComAddress(Address comAddress) {
		this.comAddress = comAddress;
	}

	public Integer getId() {
		return id;
	}

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

	public String getName() {
		return name;
	}

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

}

Customer.hbm.xml

<?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="cn.itcast.compopent.Customer" table="customers02">
      <id name="id" type="integer">
        <column name="id"/>
        <generator class="increment"/>
      </id>
      <property name="name" type="string">
          <column name="name"/>
      </property>
      
      <!-- 配置组件映射
           component标签:表示 Address类是Customer类的组成部分,在hibernate中称之为组件
       -->
      <component name="homeAddress" class="cn.itcast.compopent.Address">
         <!-- 该配置表示Address是Customer类的一部分 -->
         <parent name="customer"/>
         <property name="street" type="string">
           <column name="home_street"></column>
         </property>
         
         <property name="city" type="string">
           <column name="home_city"></column>
         </property>
         
         <property name="province" type="string">
           <column name="home_province"></column>
         </property>
         
         <property name="zipcode" type="string">
           <column name="home_zipcode"></column>
         </property>
      </component>
      
       <component name="comAddress" class="cn.itcast.compopent.Address">
          <parent name="customer"/>
         <property name="street" type="string">
           <column name="com_street"></column>
         </property>
         
         <property name="city" type="string">
           <column name="com_city"></column>
         </property>
         
         <property name="province" type="string">
           <column name="com_province"></column>
         </property>
         
         <property name="zipcode" type="string">
           <column name="com_zipcode"></column>
         </property>
      </component>
   </class>
 </hibernate-mapping>

hibernate.cfg.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
	"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
	"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
   <session-factory>
      <property name="hibernate.connection.username">root</property>
      <property name="hibernate.connection.password">root</property>
      <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
      <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/test</property>
      
      <!-- 配置数据库的方言,让hibernate知道连接的是哪个数据库-->
      <property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
   
      <!-- 配置利用javaBean和映射文件生成数据库中的表
           hibernate.hbm2ddl.auto值
              * create:执行时，先查找该表是否存在,如存在先删除表，在创建表
              * none:不能创建表,只能往表中插入数据,如表不存在抛出异常,默认值
              * update:执行时，
                          情况一:
                                先查找该表是否存在,如果表存在,直接插入,如果表不存在,先创建表，再插入数据.
                          情况二:
                                先查找该表是否存在,如果表存在,但表的结构不一样,要修改表的结构
       -->
      <property name="hibernate.hbm2ddl.auto">update</property>
      
      <!-- 显示hibernate生成的sql语句 -->
      <property name="hibernate.show_sql">true</property>
   
      <!-- 显示格式化得sql语句 -->
      <property name="hibernate.format_sql">true</property>
      
   </session-factory>
</hibernate-configuration>			

App.java

package cn.itcast.compopent;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;
import org.junit.Test;

public class App {
	private static  SessionFactory sf=null;
	
	static{
		   Configuration config=new Configuration();
	       config.configure("cn/itcast/compopent/hibernate.cfg.xml");
	       config.addClass(Customer.class);
	       sf=config.buildSessionFactory();
	}
	
    /*
     * 知识点1:测试插入
     */
	@Test
	public  void saveCustomer(){
		   Session session=sf.openSession();
		   Transaction tx=session.beginTransaction();
		   
		   Customer c=new Customer();
		   c.setName("高秀敏");
		   
		   Address homeAddress=new Address("上地三街","北京","北京","100000");
		   Address comAddress=new Address("深圳街","长春","吉林省","100006");
		   
		   c.setHomeAddress(homeAddress);
		   c.setComAddress(comAddress);
		   
		   session.save(c);
		   
		   tx.commit();
		   session.close();
	}
	
	//知识点2:测试查询
	@Test
	public  void getCustomer(){
		   Session session=sf.openSession();
		   Transaction tx=session.beginTransaction();
		   
		   Customer c=(Customer)session.get(Customer.class, 2);
		   System.out.println(c.getId()+"   "+c.getName());
		   if(c.getHomeAddress()!=null){
			   System.out.println(c.getHomeAddress().getCity()+"  "+c.getHomeAddress().getProvince());
		   }
		   
		   if(c.getComAddress()!=null){
			   System.out.println(c.getComAddress().getCity()+"  "+c.getComAddress().getProvince());
		   }
		   tx.commit();
		   session.close();
	}
	
	//知识点3:测试更新
	@Test
	public  void updateCustomer(){
		   Session session=sf.openSession();
		   Transaction tx=session.beginTransaction();
		   
		   Customer c=(Customer)session.get(Customer.class, 2);
           c.setName("楚留香");
           
		   tx.commit();
		   session.close();
	}
	
	
	
	//知识点4:测试特殊的更新
	@Test
	public  void updateOtherCustomer(){
		   Session session=sf.openSession();
		   Transaction tx=session.beginTransaction();
		   
		   Customer c=(Customer)session.get(Customer.class, 2);
		   System.out.println(c.getId()+"   "+c.getName());
		   
		   Address ha=c.getHomeAddress();
		   if(ha==null){
			   System.out.println("homeAddress为空");
		       ha=new Address("上地七街","海淀区","北京","100000");
		       c.setHomeAddress(ha);
		   }
		   
		   
		   tx.commit();
		   session.close();
	}
	
}