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>

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 + "]";
    }
    

}

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 + "]";
    }
    
    
    
    
    

}

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>

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>

7.在项目的src下的com.util包下创建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();
    }

}

9.结果自己验证...