Hibernate关联映射之_一对多

domain：

 package org.zln.hibernate.domain;

 import java.util.Set;

 /**
  * 部门Domain对象
  * Created by sherry on 000018/6/18 21:38.
  */
 public class Department {
     private int id;
     private String name;

     private Set<Employee> employeeSet;

     @Override
     public String toString() {
         return "Department{" +
                 "id=" + id +
                 ", name='" + name + '\'' +
                 '}';
     }

     public Set<Employee> getEmployeeSet() {
         return employeeSet;
     }

     public void setEmployeeSet(Set<Employee> employeeSet) {
         this.employeeSet = employeeSet;
     }

     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;
     }

 }

映射文件

 <?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="org.zln.hibernate.domain">

     <class name="Department" table="department">
         <id name="id" column="id">
             <generator class="native"/>
         </id>
         <property name="name" column="name"/>
         <!--一对多-->
         <set name="employeeSet">
             <!--主键作为条件查询员工表的外键-->
             <key column="department_id"/>
             <!--集合中存储元素的类型-->
             <one-to-many class="Employee" />
         </set>

     </class>

 </hibernate-mapping>

Dao

     public Department getDepartment(Department department){
         Department target = null;
         Session session = null;
         try {
             session = HibernateUtils.getSession();
             target = (Department) session.get(Department.class,department.getId());
             Hibernate.initialize(target.getEmployeeSet());
         }finally {
             if (session != null){
                 session.close();
             }
         }
         return target;
     }

在查询部门的时候，根据配置的一对多的关系，会将部门对应的员工信息也查询出来映射到Set中

     /**
      * 新增部门及其员工
      * @param department
      * @param employeeSet
      */
     public void addDepartment(Department department,Set<Employee> employeeSet){
         Session session = null;
         Transaction transaction = null;
         try {
             session = HibernateUtils.getSession();
             transaction = session.beginTransaction();

             department.setEmployeeSet(employeeSet);

             /*保存部门*/
             session.save(department);
             /*保存员工*/
             for (Employee employee:employeeSet){
                 session.save(employee);
             }
             transaction.commit();
         }finally {
             if (session != null){
                 session.close();
             }
         }
     }

保存的员工会自带其部门外键