hibernate —— 一对多和多对一

案例：

Employee.java

hibernate —— 一对多和多对一

package com.huarui.test;

import java.util.Set;

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

import com.huarui.entity.Department;
import com.huarui.entity.Employee;
import com.huarui.utils.SessionFactoryUtil;

public class TestEmployee {

   @Test
   public void delete() {
       // 创建session
       Session session = SessionFactoryUtil.getSessionFactory().openSession();
       Department department = (Department) session.get(Department.class, 1);

       // 开启事务
               session.beginTransaction();
               // 保存对象
               try {
                   session.delete(department);
                   // 提交事务
                   session.getTransaction().commit();
               } catch (Exception e) {
                   e.printStackTrace();
                   session.getTransaction().rollback();
               } finally {
                   // 关闭session
                   session.close();
               }
   }

   @Test
   public void save1() {
       // 创建session
       Session session = SessionFactoryUtil.getSessionFactory().openSession();
       // 创建对象
       Department department = new Department();
       department.setDepName("财务部");

       Employee employee = new Employee();
       employee.setEmpName("王子豪");

       Employee employee1 = new Employee();
       employee1.setEmpName("冯小刚");

       Employee employee2 = new Employee();
       employee2.setEmpName("杨紫琼");
       // 建立联系
       employee.setDepartment(department);
       employee1.setDepartment(department);
       employee2.setDepartment(department);
       // 开启事务
       session.beginTransaction();
       // 保存对象
       try {
           // 执行保存
           session.save(department);
           session.save(employee);
           session.save(employee1);
           session.save(employee2);
           // 提交事务
           session.getTransaction().commit();
       } catch (Exception e) {
           e.printStackTrace();
           session.getTransaction().rollback();
       } finally {
           // 关闭session
           session.close();
       }
   }

   @Test
   public void get1() {
       // 创建session
       Session session = SessionFactoryUtil.getSessionFactory().openSession();
       Department department = (Department) session.get(Department.class, 1);
       System.out.println(department.getDepName());

       Set<Employee> employees = department.getEmployee();
       for (Employee employee : employees) {
           System.out.println(employee.getEmpName());
       }

   }

   @Test
   public void save2() {
       // 创建session
       Session session = SessionFactoryUtil.getSessionFactory().openSession();
       // 创建部门
       Department department = new Department();
       department.setDepName("企划部");

       // 增加员工信息
       Employee employee = new Employee();
       employee.setEmpName("王羲之");
       Employee employee1 = new Employee();
       employee1.setEmpName("叶良车");
       Employee employee2 = new Employee();
       employee2.setEmpName("王大爷");

       // 建立联系
       department.getEmployee().add(employee);
       department.getEmployee().add(employee2);
       department.getEmployee().add(employee1);
       // 开启事务
       session.beginTransaction();
       // 保存对象
       try {
           // 执行保存
           session.save(department);
           // session.save(employee);
           // session.save(employee1);
           // session.save(employee2);
           // 提交事务
           session.getTransaction().commit();
       } catch (Exception e) {
           e.printStackTrace();
           session.getTransaction().rollback();
       } finally {
           // 关闭session
           session.close();
       }
   }
}

hibernate —— 一对多和多对一

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