hibernate关联关系-一对一

hibernate关联关系：一对一

 

模型：Person — IdCard

 

package Domain;

public class Person {
	
	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 IdCard getIdCard() {
		return idCard;
	}
	public void setIdCard(IdCard idCard) {
		this.idCard = idCard;
	}
	
	private int id;
	private String name;
	private IdCard idCard;
}

 

package Domain;

import java.util.Date;

public class IdCard {
	
	
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public Date getUsefulLife() {
		return usefulLife;
	}
	public void setUsefulLife(Date usefulLife) {
		this.usefulLife = usefulLife;
	}
	public Person getPerson() {
		return person;
	}
	public void setPerson(Person person) {
		this.person = person;
	}
	
	private int id;
	private Date usefulLife;
	private Person person;
}

 

 

<?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="Domain">

	<class name="Person" table="person">
		<id name="id">
			<generator class="native" />
		</id>
		<property name="name" />
		<one-to-one name="idCard"/>
	</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="Domain">

	<class name="IdCard" table="id_card">
		<id name="id">
			<generator class="foreign">
				<param name="property">person</param>
			</generator>
		</id>
		<property name="usefulLife" column="useful_Life"/>
		<one-to-one name="person" constrained="true"/>
	</class>
</hibernate-mapping>

 

package Dao.Test;

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

import Utils.hibernateUtil;
import Domain.Department;
import Domain.Employee;

public class One2ManyTest {
	public static void main(String[] args) {
		Department depart = add();
		queryDepart(depart.getId());
	}

	static Department queryDepart(int departId) {
		Session s = null;
		try {
			s = hibernateUtil.getSession();
			Department depart = (Department) s.get(Department.class, departId);
			System.out.println("emp  size: " + depart.getEmps().size());
			return depart;
		} finally {
			if (s != null)
				s.close();
		}
	}

	static Department add() {
		Session s = null;
		Transaction tx = null;
		try {
			Department depart = new Department();
			depart.setName("+Manager+");

			Employee emp1 = new Employee();
			emp1.setDepart(depart);// 对象模型：建立两个对象的关联
			emp1.setName("emp name1");
			
			Employee emp2 = new Employee();
			emp2.setDepart(depart);// 对象模型：建立两个对象的关联
			emp2.setName("emp name2");

			/*Set<Employee> emps = new HashSet<Employee>();
			emps.add(emp1);
			emps.add(emp2);
			depart.setEmps(emps);*/

			s = hibernateUtil.getSession();
			tx = s.beginTransaction();

			s.save(depart);
			s.save(emp1);
			s.save(emp2);
			System.out.println("-----------------------------------------");
			tx.commit();

			return depart;
		} finally {
			if (s != null)
				s.close();
		}
	}
}

 

package Dao.Test;

import java.util.Date;

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

import Utils.hibernateUtil;

import Domain.IdCard;
import Domain.Person;

public class One2OneQueryTest {
	public static void main(String[] args) {
		add();
		query(1);
	}
	
	static Person query(int id){
		Session s = null;
		Transaction tx = null;
		try{
			s = hibernateUtil.getSession();
			tx = s.beginTransaction();
			
			// 一对一 查询主对象
			// Person p = (Person)s.get(Person.class, id);
			// System.out.println( "p.getIdCard().getUsefulLife()：" + p.getIdCard().getUsefulLife());
			
			// 一对一 查询从对象
			IdCard idCard = (IdCard)s.get(IdCard.class, id);
			System.out.println("idCard.getPerson().getName()：" + idCard.getPerson().getName());
			
			tx.commit();
			//return p;
			return null;
		}finally{
			if(s != null){
				s.close();
			}
		}
	}
	
	
	static Person add(){
		Session s = null;
		Transaction tx = null;
		try{
			s = hibernateUtil.getSession();
			IdCard idCard = new IdCard();
			idCard.setUsefulLife(new Date());
			
			Person p = new Person();
			p.setName("Chen Huiyi");
			p.setIdCard(idCard);
			
			// 用Person对象来指定IdCard的id
			idCard.setPerson(p);
			
			tx = s.beginTransaction();
			s.save(p);
			s.save(idCard);
			tx.commit();
			return p;
		}finally{
			if(s != null){
				s.close();
			}
		}
	}	
}

  

 

评论

1 楼 csdn_zuoqiang 2010-08-03  

根据从对象查询主对象时候，只产生一条查询语句~！！！