7.hibernat实现双向一对多(多对一)

1.创建如下项目结构

2.在项目的src下创建hibernate.cfg.xml主配置文件

 <?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" >
 <hibernate-configuration>
   <session-factory>
      <property name="connection.driver_class">oracle.jdbc.driver.OracleDriver</property>
      <property name="connection.url">jdbc:oracle:thin:@127.0.0.1:1521:orcl</property>
      <property name="connection.username">scott</property>
      <property name="connection.password">tiger</property>
      <property name="dialect">org.hibernate.dialect.Oracle10gDialect</property>
      <property name="show_sql">true</property>
      <property name="format_sql">true</property>

      <mapping resource="com/entity/Dept.hbm.xml"/>
      <mapping resource="com/entity/Emp.hbm.xml"/>
   </session-factory>
 </hibernate-configuration>

hibernate.cfg.xml

3.在项目的src下的com.entity包下创建Dept.java

 package com.entity;

 import java.util.HashSet;
 import java.util.Set;

 public class Dept {
     /**
      * 部门编号
      */
     private int deptno;
     /**
      * 部门名称
      */
     private String dname;
     /**
      * 部门位置
      */
     private String loc;
     /**
      * 创建set集合
      */
     private Set<Emp> empset=new HashSet<Emp>();

     public Dept() {
     }
     public Dept(int deptno, String dname, String loc) {
         this.deptno = deptno;
         this.dname = dname;
         this.loc = loc;
     }

     public Dept(int deptno, String dname, String loc, Set<Emp> empset) {
         this.deptno = deptno;
         this.dname = dname;
         this.loc = loc;
         this.empset = empset;
     }
     public int getDeptno() {
         return deptno;
     }
     public void setDeptno(int deptno) {
         this.deptno = deptno;
     }
     public String getDname() {
         return dname;
     }
     public void setDname(String dname) {
         this.dname = dname;
     }
     public String getLoc() {
         return loc;
     }
     public void setLoc(String loc) {
         this.loc = loc;
     }

     public Set<Emp> getEmpset() {
         return empset;
     }
     public void setEmpset(Set<Emp> empset) {
         this.empset = empset;
     }
     @Override
     public String toString() {
         return "Dept [deptno=" + deptno + ", dname=" + dname + ", empset="
                 + empset + ", loc=" + loc + "]";
     }

 }

Dept.java

4.在项目的src下的com.entity包下创建Emp.java

 package com.entity;

 import java.util.Date;

 public class Emp {
     /**
      * 员工编号
      */
     private Integer empno;
     /**
      * 员工姓名
      */
     private String ename;
     /**
      * 员工工作
      */
     private String job;
     /**
      * 员工领导编号
      */
     private Integer mgr;
     /**
      * 员工雇佣日期
      */
     private Date hiredate;
     /**
      * 员工工资
      */
     private Integer sal;
     /**
      * 员工奖金
      */
     private Integer comm;
     /**
      * 部门外键
      * 引入部门对象
      */
     private Dept dept;
     public Emp() {
         super();
     }
     public Emp(Integer empno, String ename, String job, Integer mgr,
             Date hiredate, Integer sal, Integer comm, Dept dept) {
         this.empno = empno;
         this.ename = ename;
         this.job = job;
         this.mgr = mgr;
         this.hiredate = hiredate;
         this.sal = sal;
         this.comm = comm;
         this.dept = dept;
     }

     public Integer getEmpno() {
         return empno;
     }
     public void setEmpno(Integer empno) {
         this.empno = empno;
     }
     public String getEname() {
         return ename;
     }
     public void setEname(String ename) {
         this.ename = ename;
     }
     public String getJob() {
         return job;
     }
     public void setJob(String job) {
         this.job = job;
     }
     public Integer getMgr() {
         return mgr;
     }
     public void setMgr(Integer mgr) {
         this.mgr = mgr;
     }
     public Date getHiredate() {
         return hiredate;
     }
     public void setHiredate(Date hiredate) {
         this.hiredate = hiredate;
     }
     public Integer getSal() {
         return sal;
     }
     public void setSal(Integer sal) {
         this.sal = sal;
     }
     public Integer getComm() {
         return comm;
     }
     public void setComm(Integer comm) {
         this.comm = comm;
     }
     public Dept getDept() {
         return dept;
     }
     public void setDept(Dept dept) {
         this.dept = dept;
     }
     @Override
     public String toString() {
         return "Emp [comm=" + comm + ", dept=" + dept + ", empno=" + empno
                 + ", ename=" + ename + ", hiredate=" + hiredate + ", job="
                 + job + ", mgr=" + mgr + ", sal=" + sal + "]";
     }

 }

Emp.java

5.在项目的src下的com.entity包下创建Dept.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>
 <class name="com.entity.Dept" table="DEPT" schema="SCOTT" lazy="true">
   <!-- 主键配置 -->
    <id name="deptno" type="java.lang.Integer" column="DEPTNO">
       <!-- 主键由应用程序负责生成 -->
       <generator class="assigned"/>
    </id>
    <!-- 部门名称 -->
    <property name="dname" type="java.lang.String" column="DNAME"/>

    <!-- 部门位置 -->
    <property name="loc" type="java.lang.String" column="LOC"/>

    <!--
      一对多映射
      cascade级联：操作主表时同时操作从表
    cascade="save-update" 级联增和该
    cascade="delete" 级联删除
    cascade="none" 忽略关联
    cascade="all"级联增删改
    -->
    <!-- inverse="false"主动维护关联关系，false主动方，true被动方（当从表修改时，主表不修改）
    inverse="false"两条update
    inverse="true" 一条update -->
    <set name="empset" cascade="all" inverse="true" order-by="ename asc">
       <!-- 本表主键列，对应emp的外键列 -->
       <key column="DEPTNO"></key>
       <!-- 集合存储的数据类型 -->
       <one-to-many class="com.entity.Emp"/>
    </set>
 </class>
 </hibernate-mapping>

Dept.hbm.xml

6.在项目的src下的com.entity包下创建Emp.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>
    <class name="com.entity.Emp" table="EMP" schema="scott" >
       <id name="empno" type="java.lang.Integer" column="EMPNO">
          <generator class="assigned"/>
       </id>
       <property name="ename" type="java.lang.String" column="ENAME"/>
       <property name="job" type="java.lang.String" column="JOB"/>
       <property name="mgr" type="java.lang.Integer" column="MGR"/>
       <property name="hiredate" type="java.util.Date" column="HIREDATE"/>
       <property name="sal" type="java.lang.Integer" column="SAL"/>
       <property name="comm" type="java.lang.Integer" column="COMM" not-null="false" />

       <!-- 多对一映射：name是emp中外键字段引用的对象，class是对象的类型，column是数据库中对应的外键列字段名 -->
       <many-to-one name="dept" class="com.entity.Dept" column="DEPTNO"/>
    </class>
 </hibernate-mapping>

Emp.hbm.xml

7.在项目的src下的com.util包下创建HibernateUtil.java

HibernateUtil.java

8.在项目的src下的com.dao包下创建EmpDao.java

 package com.dao;

 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.List;
 import java.util.Set;
 import java.util.logging.SimpleFormatter;

 import org.hibernate.Query;
 import org.hibernate.Session;
 import org.hibernate.Transaction;

 import com.entity.Dept;
 import com.entity.Emp;
 import com.util.HibernateUtil;

 public class DeptDao {

     public static void main(String[] args) {
         System.out.println("--------------------1.保存：部门对象，插入2条，修改1条------------------");
         //saveDept();
         System.out.println("----------------2.删除部门数据级联删除员工--------------------------------------");
     //    deleteDept(4);
         System.out.println("----------------3.修改员工--------------------------------------");
         //updateEmp(2,1);
         System.out.println("-------------------4.查询某部门下的所有员工，并按姓名排序order-by-------------------------------------");
         //getEmpByDeptno(10);
         System.out.println("-------------------5.查询某部门信息--lazy=false-----------------------------------");
         //getDeptByDeptno(10);
         System.out.println("-------------------6.查询某部门信息--lazy=true-----------------------------------");
         saveEmp(10);

     }
     /**
      * -6.查询某部门信息--lazy=true懒加载  ，查的时候用load懒加载查询的方式
      * @param id
      */
     private static void saveEmp(int id) {
           Session session=HibernateUtil.getSession();
           Transaction tx=session.beginTransaction();

             //查单条load懒加载
             Dept dept=(Dept) session.load(Dept.class, id);
             Date date=null;
             try {
                 date = new SimpleDateFormat("yyyy-MM-dd").parse("2013-3-3");
             } catch (ParseException e) {
                 e.printStackTrace();
             }
             Emp emp=new Emp(6, "holly", "教员", 2, date, 2300, 200, dept);

             //添加员工信息
             session.save(emp);
             tx.commit();
             System.out.println("添加成功");

             HibernateUtil.closeSession();

     }
     /**
      * 5.查询某部门信息
      * dept类级别的lazy=false 立即加载  ，查的时候用get立即加载的方式
      * 1条查询sql
      * @param i
      */
     private static void getDeptByDeptno(int id) {
         Session session=HibernateUtil.getSession();

         //查单条
         Dept dept=(Dept) session.load(Dept.class, id);

         HibernateUtil.closeSession();

     }
     /**
      * 4.查询某部门下的所有员工，并按姓名排序order-by
      * @param i
      */
     private static void getEmpByDeptno(int id) {
         Session session=HibernateUtil.getSession();

         //查单条
         Dept dept=(Dept) session.get(Dept.class, id);
         Set<Emp> emps=dept.getEmpset();
         for (Emp emp : emps) {
             System.out.println(emp.getEname());
         }
         HibernateUtil.closeSession();

     }
   /**
    * 3.修改员工
    * @param empno
    * @param deptno
    */
     private static void updateEmp(int empno,int deptno) {
         Session session=HibernateUtil.getSession();
         //2.开启事务
         Transaction tx=session.beginTransaction();
         //查单条
         Dept dept=(Dept) session.load(Dept.class, deptno);
         Emp emp=(Emp) session.load(Emp.class, empno);
         /*
          * 监测到Emp对象的属性发生变化，所以执行
          *  update
         scott.EMP
      set
         ENAME=?,
         JOB=?,
         MGR=?,
         HIREDATE=?,
         SAL=?,
         COMM=?,
         DEPTNO=?
     where
         EMPNO=?
          */
         emp.setDept(dept);
     /*(inverse=false)主动，监测到Dept对象的属性发生变化，所以执行
         update
         scott.EMP
         set
             DEPTNO=?
         where
             EMPNO=?
       (inverse=true)被动，没有上面一条update
       */
         dept.getEmpset().add(emp);
         System.out.println("修改成功");

         tx.commit();
         HibernateUtil.closeSession();

     }

     /**
      * 2.删除
      * @param id
      */
     private static void deleteDept(int id) {
         Session session=HibernateUtil.getSession();
         //2.开启事务
         Transaction tx=session.beginTransaction();
         //查单条
         Dept dept=(Dept) session.get(Dept.class, id);
         if(dept!=null){
             session.delete(dept);
             System.out.println("删除成功");
         }else{
             System.out.println("该条数据不存在");
         }
         tx.commit();
         HibernateUtil.closeSession();

     }

     /**
      * 1.保存：1部门和2员工-----3条sql
      */
     private static void saveDept() {
         //1.开启Session
         Session session=HibernateUtil.getSession();

         //2.开启事务
         Transaction tx=session.beginTransaction();

         //3.执行操作
         //创建部门对象
         Dept dept=new Dept(3, "教职部", "安德门");
         Date date=null;
         try {
             date = new SimpleDateFormat("yyyy-MM-dd").parse("2013-3-3");
         } catch (ParseException e) {
             e.printStackTrace();
         }

         //创建员工对象
         Emp emp1=new Emp(4, "holly", "教员", 2, date, 2300, 200, dept);

         //向集合总添加员工信息（1条sql）
         dept.getEmpset().add(emp1);

         //保存Dept对象(2条插入)
         session.save(dept);

         //4.提交事务
         tx.commit();
         System.out.println("Emp保存成功");

         //5.关闭Session
         HibernateUtil.closeSession();
     }

 }

DeptDao.java

9.结果自己验证...