【hibernate实例】单项多对一增加查找

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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();  
          
    }  
}  