建立持久化類和配置文件，可以用MyEclipse直接生成

持久化類

package entity;import java.util.Date;public class Emp implements java.io.Serializable {    // Fields    PRivate Short empno;    private Dept dept;    private String ename;    private String job;    private Short mgr;    private Date hiredate;    private Double sal;    private Double comm;    // Constructors    /** default constructor */    public Emp() {    }    /** minimal constructor */    public Emp(Short empno) {        this.empno = empno;    }    /** full constructor */    public Emp(Short empno, Dept dept, String ename, String job, Short mgr,            Date hiredate, Double sal, Double comm) {        this.empno = empno;        this.dept = dept;        this.ename = ename;        this.job = job;        this.mgr = mgr;        this.hiredate = hiredate;        this.sal = sal;        this.comm = comm;    }    // Property accessors    public Short getEmpno() {        return this.empno;    }    public void setEmpno(Short empno) {        this.empno = empno;    }    public Dept getDept() {        return this.dept;    }    public void setDept(Dept dept) {        this.dept = dept;    }    public String getEname() {        return this.ename;    }    public void setEname(String ename) {        this.ename = ename;    }    public String getJob() {        return this.job;    }    public void setJob(String job) {        this.job = job;    }    public Short getMgr() {        return this.mgr;    }    public void setMgr(Short mgr) {        this.mgr = mgr;    }    public Date getHiredate() {        return this.hiredate;    }    public void setHiredate(Date hiredate) {        this.hiredate = hiredate;    }    public Double getSal() {        return this.sal;    }    public void setSal(Double sal) {        this.sal = sal;    }    public Double getComm() {        return this.comm;    }    public void setComm(Double comm) {        this.comm = comm;    }}

package entity;import java.util.HashSet;import java.util.Set;public class Dept implements java.io.Serializable {    // Fields    private Byte deptno;    private String dname;    private String loc;    private Set emps = new HashSet(0);    // Constructors    /** default constructor */    public Dept() {    }    /** minimal constructor */    public Dept(Byte deptno) {        this.deptno = deptno;    }    /** full constructor */    public Dept(Byte deptno, String dname, String loc, Set emps) {        this.deptno = deptno;        this.dname = dname;        this.loc = loc;        this.emps = emps;    }    // Property accessors    public Byte getDeptno() {        return this.deptno;    }    public void setDeptno(Byte deptno) {        this.deptno = deptno;    }    public String getDname() {        return this.dname;    }    public void setDname(String dname) {        this.dname = dname;    }    public String getLoc() {        return this.loc;    }    public void setLoc(String loc) {        this.loc = loc;    }    public Set getEmps() {        return this.emps;    }    public void setEmps(Set emps) {        this.emps = emps;    }}

emp類配置文件

<?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="entity.Emp" table="EMP" schema="SCOTT">        <id name="empno" type="java.lang.Short">            <column name="EMPNO" precision="4" scale="0" />            <generator class="assigned" />        </id>        <many-to-one name="dept" class="entity.Dept" fetch="select">            <column name="DEPTNO" precision="2" scale="0" />        </many-to-one>        <property name="ename" type="java.lang.String">            <column name="ENAME" length="10" />        </property>        <property name="job" type="java.lang.String">            <column name="JOB" length="9" />        </property>        <property name="mgr" type="java.lang.Short">            <column name="MGR" precision="4" scale="0" />        </property>        <property name="hiredate" type="java.util.Date">            <column name="HIREDATE" length="7" />        </property>        <property name="sal" type="java.lang.Double">            <column name="SAL" precision="7" />        </property>        <property name="comm" type="java.lang.Double">            <column name="COMM" precision="7" />        </property>    </class></hibernate-mapping>

dept類配置文件

<?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="entity.Dept" table="DEPT" schema="SCOTT">        <id name="deptno" type="java.lang.Byte">            <column name="DEPTNO" precision="2" scale="0" />            <generator class="assigned" />        </id>        <property name="dname" type="java.lang.String">            <column name="DNAME" length="14" />        </property>        <property name="loc" type="java.lang.String">            <column name="LOC" length="13" />        </property>        <set name="emps" inverse="true">            <key>                <column name="DEPTNO" precision="2" scale="0" />            </key>            <one-to-many class="entity.Emp" />        </set>    </class></hibernate-mapping>

<?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="dialect">            org.hibernate.dialect.Oracle9Dialect        </property>        <property name="connection.url">            jdbc:oracle:thin:@localhost:1521:orcl        </property>        <property name="connection.username">root</property>        <property name="connection.passWord">root</property>        <property name="connection.driver_class">            oracle.jdbc.OracleDriver        </property>            <mapping resource="entity/Emp.hbm.xml" />        <mapping resource="entity/Dept.hbm.xml" />    </session-factory></hibernate-configuration>

• 根據結果獲得總亡錄數：

Querty query=session.createQuery("from Emp");List list=query.list();int count=list.size();

• 計算總頁數：

int totalPages=(count%pageSize==0)?(count/pageSize):(count/pageSize+1);

• 實現分頁：

query.setFirstResult((pageIndex-1)*pageSize); //開始記錄數query.setMaxResults(pageSize);//每頁顯示最大記錄數List resultList=query.list();  //每頁顯示的記錄集合 

查詢全部員工

/*     * 查詢員工表內容     */    public static void findEmp(){        Session session=new Configuration().configure().buildSessionFactory().openSession();        //查詢員工表按入職日期升序排，日期相同按名字降序        String hql=" from Emp e order by e.hiredate ,e.ename desc ";        Query query=session.createQuery(hql);        List<Emp> emps=query.list();        for (Emp emp : emps) {            System.out.println("員工編號："+emp.getEmpno()+"/t姓名： "+emp.getEname()+"/t入職日期："+emp.getHiredate()+"/t部門名稱："+emp.getDept().getDname());        }    }

分頁查詢

/*     * 分頁查詢     */    public static void pageDisplay(){        Session session=new Configuration().configure().buildSessionFactory().openSession();        String hql="from Emp";        //第幾頁        int pageIndex=4;        //每頁顯示記錄數        int pageSize=4;        Query query=session.createQuery(hql);        //起始記錄數        query.setFirstResult((pageIndex-1)*pageSize);        //每頁顯示最多記錄數        query.setMaxResults(pageSize);        List<Emp> emps=query.list();        for (Emp emp : emps) {            System.out.println("員工編號："+emp.getEmpno()+"/t姓名： "+emp.getEname()+"/t入職日期："+emp.getHiredate()+"/t部門名稱："+emp.getDept().getDname());        }            }

部門表中有個40部門，員工表中沒有人是40部門的，

首先向EMP表中插入一條沒有部門的記錄

insert into emp(empno,ename,job,hiredate,sal)values(8888,'張三','業務員',sysdate,800);

String hql="from Dept d inner join d.emps";

String hql="from Dept d left join d.emps";

String hql="from Dept d right join d.emps";