a实体 多对一 b实体

a实体中有b实体的引用 

public class User1 {

	private int id;

	private String name;

	private Department department;



	public Department getDepartment() {

		return department;

	}



	public void setDepartment(Department department) {

		this.department = department;

	}



	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 class Department {

	private Integer id;

	private String name;

	private Set<User1> users;

	

	public Set<User1> getUsers() {

		return users;

	}



	public void setUsers(Set<User1> users) {

		this.users = users;

	}



	public Department(){}

	

	public Department(String name) {

		this.name = name;

	}

	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;

	}

	

	

}

<?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="cn.itcast.hibernate.domain">



	<class name="User1" table="user1">

		<id name="id" unsaved-value="-1">

			<generator class="native" />

		</id>

		<property name="name"/>

		<many-to-one name="department" column="deptid"/>

	</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="cn.itcast.hibernate.domain">



	<class name="Department" table="Department">

		<id name="id" unsaved-value="-1">

			<generator class="native" />

		</id>

		<property name="name"/>

		<set name="users">

		  <key column="deptid"/>

		  <one-to-many class="User1"/>

		</set>

	</class>

</hibernate-mapping>

import java.util.HashSet;

import java.util.Set;



import org.hibernate.Session;

import org.hibernate.Transaction;



import cn.itcast.hibernate.HibernateUtil;

import cn.itcast.hibernate.domain.Department;

import cn.itcast.hibernate.domain.User1;



public class ManyToOneTest {



	public static void main(String[] args) {

		Session session = null;

		Transaction tx = null;

		

/*		try {

			session = HibernateUtil.getSession();

			tx = session.beginTransaction();

			

			Department department = new Department("研发部");

			

			User1 user1 = new User1();

			user1.setName("小新");

			user1.setDepartment(department);

			

			session.save(department);

			session.save(user1);

					

			tx.commit();

		} catch (HibernateException e) {

			if (tx!=null) {

				tx.rollback();

			}

			e.printStackTrace();

		}finally{

			if (session!=null) {

				session.close();				

			}

		}*/

		

/*		//获得

		try {

			session = HibernateUtil.getSession();

			

			User1 user1 = (User1)session.get(User1.class, 5);

			System.out.println(user1.getName());

			

			Department department = user1.getDepartment();

			System.out.println(department.getName());

			

			session.close();

			

		} catch (Exception e) {

			e.printStackTrace();

		}*/

		

		try {

			session = HibernateUtil.getSession();

			tx = session.beginTransaction();

			

			//新建几个用户

			User1 usera = new User1();

			usera.setName("一号");

			

			User1 userb = new User1();

			userb.setName("二号");

			

			Set<User1> users = new HashSet<User1>();

			users.add(usera);

			users.add(userb);

			

			//新建部门

			Department department = new Department("业务部");

			department.setUsers(users);



			session.save(department);

			

			session.save(usera);

			session.save(userb);

			

			

			tx.commit();

		} catch (Exception e) {

			e.printStackTrace();

		}

		

	}



}