hibernate中的一对多（双向关系）

Dept

package com.wxh.dto;

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

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.OneToMany;

@Entity
public class Dept {
  
  private int dno;
  private String dname;
  private String tel; 
  
  private Set<Emp> emps=new HashSet();
  
  public Dept() {
  } 
  
  public Dept(int dno, String dname, String tel) {
    this.dno = dno;
    this.dname = dname;
    this.tel = tel;
  }

  @Id
  public int getDno() {
    return dno;
  }
  public void setDno(int dno) {
    this.dno = dno;
  }
  public String getDname() {
    return dname;
  }
  public void setDname(String dname) {
    this.dname = dname;
  }
  public String getTel() {
    return tel;
  }
  public void setTel(String tel) {
    this.tel = tel;
  }

  @OneToMany(fetch=FetchType.LAZY,cascade={CascadeType.ALL},mappedBy="dept")
  public Set<Emp> getEmps() {
    return emps;
  }

  public void setEmps(Set<Emp> emps) {
    this.emps = emps;
  } 
}

Emp

package com.wxh.dto;

import javax.persistence.CascadeType;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.ManyToOne;

@Entity
public class Emp {
  
  private int eno;
  private String ename;
  private String job;
  private double sal;
  
  private Dept dept;  

  public Emp() {
  } 
  
  public Emp(int eno, String ename, String job, double sal) {
    super();
    this.eno = eno;
    this.ename = ename;
    this.job = job;
    this.sal = sal;
  }
  
  @Id
  public int getEno() {
    return eno;
  }

  public void setEno(int eno) {
    this.eno = eno;
  }

  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 double getSal() {
    return sal;
  }

  public void setSal(double sal) {
    this.sal = sal;
  }

  @ManyToOne(fetch=FetchType.EAGER,cascade={CascadeType.ALL})
  @JoinColumn(name="dno")
  public Dept getDept() {
    return dept;
  }

  public void setDept(Dept dept) {
    this.dept = dept;
  } 
    
}

Test

package test;

import org.hibernate.Session;

import com.wxh.dto.Dept;
import com.wxh.dto.Emp;
import com.wxh.sessionfactory.HibernateSessionFactory;

public class Test {

  public static void main(String[] args) {  
    
    Dept d=new Dept(10,"研发部","10086");
    Emp e1=new Emp(1,"张三","项目经理",12000);
    Emp e2=new Emp(2,"李四","测试经理",8000);
    Emp e3=new Emp(3,"王五","产品经理",22000);
    
    //指定员工所在部门
    e1.setDept(d);
    e2.setDept(d);
    e3.setDept(d);
    
    //将员工对象设置到集合中
    d.getEmps().add(e1);
    d.getEmps().add(e2);
    d.getEmps().add(e3);    
    
    Session session=HibernateSessionFactory.getSession();   
    session.beginTransaction(); 
    session.save(d);
    session.getTransaction().commit();    
  }
}

hibernate.cfg.xml

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
  "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
  "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
  <session-factory>
    <property name="hbm2ddl.auto">update</property>
  <property name="dialect">
    org.hibernate.dialect.Oracle9Dialect
  </property>
  <property name="connection.url">
    jdbc:oracle:thin:@127.0.0.1:1521:orcl
  </property>
  <property name="connection.username">hibernate</property>
  <property name="connection.password">m123</property>
  <property name="connection.driver_class">
    oracle.jdbc.driver.OracleDriver
  </property>
  <property name="myeclipse.connection.profile">oracle</property>
  <property name="show_sql">true</property>
  <property name="format_sql">true</property> 

  <mapping class="com.wxh.dto.Dept"/>
  <mapping class="com.wxh.dto.Emp"/>    
  </session-factory>
</hibernate-configuration>