【hibernate实例】赵雅智_单项多对一增加查找

创建部门表department

创建雇员表employee

新建持久化类

Department.java

package www.hbsi.net.many2one;

public class Department  {
	private Integer id;
	private String name;

	public Integer getId() {
		return this.id;
	}

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

	public String getName() {
		return this.name;
	}

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

Employee.java

package www.hbsi.net.many2one;
public class Employee {
	private Integer id;
	private Department department;//反应了对象之间的关系
	private String username;
	
	public Integer getId() {
		return this.id;
	}

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

	public Department getDepartment() {
		return this.department;
	}

	public void setDepartment(Department department) {
		this.department = department;
	}

	public String getUsername() {
		return this.username;
	}

	public void setUsername(String username) {
		this.username = username;
	}

}

新建映射文件

Department.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 package="www.hbsi.net.many2one">
    <class name="Department" table="department" catalog="hibernate">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="native" />
        </id>
        <property name="name" column ="name" type="string" />
    </class>
</hibernate-mapping>

Employee.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 package="www.hbsi.net.many2one">
    <class name="Employee" table="employee">
        <id name="id" type="java.lang.Integer">
            <column name="id" />
            <generator class="native" />
        </id>
        <property name="username" type="string" column ="username" />
        <many-to-one name="department" column ="dept_id" />

    </class>
</hibernate-mapping>

更改hibernate映射问价的mapping属性

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">

<!-- Generated by MyEclipse Hibernate Tools.                   -->
<hibernate-configuration>

	<session-factory>
		<property name="dialect">
			org.hibernate.dialect.MySQLDialect
		</property>
		<property name="connection.url">
			jdbc:mysql://localhost:3306/hibernate
		</property>
		<property name="connection.username">root</property>
		<property name="connection.password">123456</property>
		<property name="connection.driver_class">
			com.mysql.jdbc.Driver
		</property>
		<property name="show_sql">true</property>
		<property name="hbm2ddl.auto">update</property>
		<mapping resource="www/hbsi/net/many2one/Department.hbm.xml" />
		<mapping resource="www/hbsi/net/many2one/Employee.hbm.xml" />

	</session-factory>

</hibernate-configuration>

创建测试类

Many2one.java

package www.hbsi.net.many2one;

import javax.persistence.Temporal;

import org.hibernate.Session;
import org.junit.Test;

import www.hbsi.net.util.HibernateSessionFactory;

public class Many2one {
	@Test
	public void add(){
		Session session = HibernateSessionFactory.getSession();
		session.beginTransaction();
		
		Department department = new Department();
		department.setName("软件系");
		
		Employee employee1 = new Employee();
		employee1.setUsername("Nacy");
		employee1.setDepartment(department);
		
		Employee employee2 = new Employee();
		employee2.setUsername("Tom");
		employee2.setDepartment(department);
		
		session .save(department);
		session .save(employee1);
		session .save(employee2);
		session.getTransaction().commit();
		HibernateSessionFactory.closeSession();
	}
}

控制台输出：

department表

employee表

查找：

Many2one.java

/**
 * 先保存部门在保存雇员
 * 一般推荐这种方法
 */
package www.hbsi.net.many2one;

import org.hibernate.Session;
import org.junit.Test;

import www.hbsi.net.util.HibernateSessionFactory;

public class Many2one {
	@Test
	public void add(){
		Session session = HibernateSessionFactory.getSession();
		session.beginTransaction();
		
		Department department = new Department();
		department.setName("软件系");
		
		Employee employee1 = new Employee();
		employee1.setUsername("Nacy");
		employee1.setDepartment(department);
		
		Employee employee2 = new Employee();
		employee2.setUsername("Tom");
		employee2.setDepartment(department);
		
		session .save(department);
		session .save(employee1);
		session .save(employee2);
		session.getTransaction().commit();
		HibernateSessionFactory.closeSession();
	}
	
	/**
	 * 通过雇员ID查找所属部门
	 */
	@Test
	public void find() {
		Session session = HibernateSessionFactory.getSession();
		session.beginTransaction();
		
		Employee employee = (Employee) session.get(Employee.class, 5);
		System.out.println(employee.getUsername()+"--"+employee.getDepartment().getName());
		
		session.getTransaction().commit();
		HibernateSessionFactory.closeSession();
		
	}
}