欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

Hibernate 的查询语言 HQL 与高级查询

程序员文章站 2022-06-02 16:20:58
...

Hibernate  的查询语言 HQL  与高级查询

数据库操作实现类的开发

import java.util.List;
import org.hibernate.Query;
import org.hibernate.SQLQuery;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.sf.dao.IDepartmentDao;
import org.sf.entity.Department;
import org.sf.util.HibernateSessionFactory;
public class DepartmentDaoImpl implements IDepartmentDao {
	/**
	 *  取得所有的系院信息集合
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public List<Department> getAllDepartmentList(){
		List<Department> list = null;
		Session session = HibernateSessionFactory.getSession();
		Query q=session.createQuery("from Department");
		list = q.list();
		session.close();
		return list;
	}
	/**
	 *  通过id 取得某个系院信息
	 * @param id
	 * @return
	 */
	public Department getDepartmentById(int id){
		Department department = null;
		Session session = HibernateSessionFactory.getSession();
		Query q =session.createQuery("from Department where id=:id").setParameter("id",
				id);
		department=(Department)q.uniqueResult();
		session.close();
		return department;
	}
	/**
	 *  添加系院信息
	 * @param department
	 * @return
	 */
	public Department addDepartment(Department department){
		Session session = HibernateSessionFactory.getSession();
		Transaction tran = session.beginTransaction();
		session.save(department);
		tran.commit();
		session.close();
		return department;
	}
	/**
	 *  修改选定的系院信息
	 * @param department
	 */
	public void editDepartment(Department department){
		Session session = HibernateSessionFactory.getSession();	
		Transaction tran = session.beginTransaction();
		Department depEdit = (Department) session.load(Department.class,
				department.getId());
		depEdit.setBm(department.getBm());
		depEdit.setMc(department.getMc());
		depEdit.setTell(department.getTell());
		depEdit.setLeader(department.getLeader());
		session.update(depEdit);
		tran.commit();
		session.close();
	}
	/**
	 *  通过id 删除系院信息
	 * @param id
	 * @return
	 */
	public int delDepartmentById(int id){
		int i = 0;
		Session session = HibernateSessionFactory.getSession();
		Transaction tran = session.beginTransaction();
		SQLQuery q = (SQLQuery) session.createSQLQuery("delete from department where
				id=:id").setParameter("id", id);
				q.executeUpdate();
				tran.commit();
				session.close();
				return i;
	}
}

  制作 IStudentDao  接口及 及 StudentDaoImpl 

 

import java.util.List;
import org.sf.entity.Student;
/**
 *  学生数据库操作接口
 * @author  宋锋
 * @date 2013-04-25
 */
public interface IStudentDao {
	/**
	 *  取得所有的学生信息
	 * @return
	 */
	public List<Student> getAllStudentList();
	/**
	 *  通过 id  取得某个学生信息
	 * @param id
	 * @return
	 */
	public Student getStuentById(int id);
	/**
	 *  通过学号和密码取得学生信息,用于登录
	 * @param stunumber
	 * @param stupwd
	 * @return
	 */
	public Student getStudentByStunumberAndStupwd(String stunumber, String stupwd);
	/**
	 *  取得学生的总数信息
	 * @return
	 */
	public int getStudentCount();
	/**
	 *  取得学生分页信息
	 * @param pageNum
	 * @param pageSize
	 * @return
	 */
	public List<Student> getStudentPageList(int pageNum, int pageSize);
	/**
	 *  通过系院 id  取得学生信息
	 * @param depid
	 * @return
	 */
	public List<Student> getStudentListByDepid(int depid);
	/**
	 *  添加学生信息
	 * @param student
	 * @return
	 */
	public Student addStudent(Student student);
	/**
	 *  修改选定的学生信息
	 * @param student
	 */
	public void editStudent(Student student);
	/**
	 *  删除学生信息
	 * @param id
	 * @return
	 */
	public int delStudentById(int id);
}

数据库操作类的开发

import java.util.List;
import org.hibernate.Query;
import org.hibernate.SQLQuery;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.sf.entity.Student;
import org.sf.util.HibernateSessionFactory;
import org.sf.dao.IStudentDao;
/**
 *  学生数据库操作实现类
 * @author  宋锋
 * @date 2013-04-25
 */
public class StudentDaoImpl implements IStudentDao {
	/**
	 *  取得所有的学生信息
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public List<Student> getAllStudentList(){
		List<Student> list = null;
		Session session = HibernateSessionFactory.getSession();
		Query q = session.createQuery("from Student");
		list = q.list();
		session.close();
		return list;
	}
	/**
	 *  通过id 取得某个学生信息
	 * @param id
	 * @return
	 */
	public Student getStuentById(int id){
		Student student = null;
		Session session = HibernateSessionFactory.getSession();
		Query q = session.createQuery("from Student where id=?");
		q.setInteger(0, id);
		student = (Student)q.uniqueResult();
		session.close();
		return student;
	}
	/**
	 *  通过学号和密码取得学生信息,用于登录
	 * @param stunumber
	 * @param stupwd
	 * @return
	 */
	public Student getStudentByStunumberAndStupwd(String stunumber, String stupwd){
		Student student = null;
		Session session = HibernateSessionFactory.getSession();
		Query q = session.createQuery("from Student where stunumber=? and stupwd=?");
		q.setString(0, stunumber);
		q.setString(1, stupwd);
		student = (Student)q.uniqueResult();
		session.close();
		return student;
	}
	
	/**
	 *  取得学生的总数信息
	 * @return
	 */
	public int getStudentCount(){
		int count = 0;
		Session session = HibernateSessionFactory.getSession();
		Query q = session.createQuery("select count(s) from Student s");
		Number number = (Number)q.uniqueResult();
		count = number.intValue();
		session.close();
		return count;
	}
	/**
	 *  取得学生分页信息
	 * @param pageNum
	 * @param pageSize
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public List<Student> getStudentPageList(int pageNum, int pageSize){
		List<Student> list = null;
		Session session = HibernateSessionFactory.getSession();
		Query q = session.createQuery("from Student");
		q.setFirstResult((pageNum-1)*pageSize);
		q.setMaxResults(pageSize);
		list = q.list();
		session.close();
		return list;
	}
	/**
	 *  通过 系院id 取得学生信息
	 * @param depid
	 * @return
	 */
	@SuppressWarnings("unchecked")
	public List<Student> getStudentListByDepid(int depid){
		List<Student> list = null;
		Session session = HibernateSessionFactory.getSession();
		Query q= session.createQuery("from Student where department.id=?");
		q.setInteger(0, depid);
		list = q.list();
		session.close();
		return list;
	}
	/**
	 *  添加学生信息
	 * @param student
	 * @return
	 */
	public Student addStudent(Student student){
		Session session = HibernateSessionFactory.getSession();
		Transaction tran = session.beginTransaction();
		session.save(student);
		tran.commit();
		session.close();
		return student;
	}
	/**
	 *  修改选定的学生信息
	 * @param student
	 */
	public void editStudent(Student student){
		Session session = HibernateSessionFactory.getSession();
		Transaction tran = session.beginTransaction();
		Student stuEdit = (Student)session.load(Student.class, student.getId());
		stuEdit.setStunumber(student.getStunumber());
		stuEdit.setStuname(student.getStuname());
		stuEdit.setStupwd(student.getStupwd());
		stuEdit.setDepartment(student.getDepartment());
		session.update(stuEdit);
		tran.commit();
		session.close();
	}
	/**
	 *  删除学生信息
	 * @param id
	 * @return
	 */
	public int delStudentById(int id){
		int i = 0;
		Session session = HibernateSessionFactory.getSession();
		Transaction tran = session.beginTransaction();
		SQLQuery sq= session.createSQLQuery("delete from student where id=:id");
		sq.setParameter("id", id);
		i = sq.executeUpdate();
		tran.commit();
		session.close();
		return i;
	}
}

修改 Student.hbm.xml 中 中的 的 many-to-one 关系

<many-to-one name="department" class="org.sf.entity.Department" fetch="select" lazy="false">
<column name="depid">
<comment> 系别id</comment>
</column>
</many-to-one>

实现 students.jsp  页面

<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title> 取得并显示所有的学生</title>
</head>
<body>
<jsp:useBean id="stuDao" class="org.sf.dao.impl.StudentDaoImpl"></jsp:useBean>
<table align="center" border="1">
<tr>
<th> 学号</th>
<th> 姓名</th>
<th> 系院</th>
</tr>
<c:forEach var="stu" items="${stuDao.allStudentList}">
<tr>
<td>${stu.stunumber}</td>
<td>${stu.stuname}</td>
<td>${stu.department.mc}</td>
</tr>
</c:forEach>
</table>
</body>
</html>

Hibernate 的查询语言 HQL 与高级查询

  制作学生的分页显示 pagestudents.jsp

 

Hibernate 的查询语言 HQL 与高级查询

<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>
<%@page import="org.sf.dao.impl.StudentDaoImpl"%>
<%@page import="org.sf.dao.IStudentDao"%>
<%@page import="org.sf.entity.Student"%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title> 分页显示学生信息</title>
</head>
<body>
<table align="center" border="1">
<tr>
<th> 学号</th>
<th> 姓名</th>
<th> 系院</th>
</tr>
<%
String strPageNum = request.getParameter("pageNum");
int pageNum = 1; // 当前 页面
int pageSize = 3; // 每页的记录条数
int pageSum = 0; // 总页面数
if(strPageNum!=null) // 如果取到了数据,则为调用而来
{
pageNum = Integer.parseInt(strPageNum);
}
IStudentDao stuDao = new StudentDaoImpl();
List<Student> list = stuDao.getStudentPageList(pageNum, pageSize);
 iCount = stuDao.getStudentCount(); // 记录总数
// 计算总页面数
pageSum = iCount/pageSize;
if(iCount%pageSize!=0){
pageSum+=1;
}
if(list.size()>0){
for(Student stu:list){
%>
<tr>
<td><%=stu.getStunumber() %></td>
<td><%=stu.getStuname() %></td>
<td><%=stu.getDepartment().getMc() %></td>
</tr>
<%
}
}
%>
<tr><td colspan="3" align="center">
<%
out.print(" 第["+pageNum+"] 页,共["+pageSum+"] 页");
if(pageNum<2){
%>
上 上1 页
<%
}else{
%>
<a href="pagestudents.jsp?pageNum=<%=pageNum-1 %>" > 上1 页</a>
<%
}
%>
  
<%
if(pageNum>=pageSum){
%>
上 上1 页
<%
}else{
%>
<a href="pagestudents.jsp?pageNum=<%=pageNum+1 %>" > 下1 页</a>
<%
}
%>
</td></tr>
</table>
</body>
</html>

  制作通过系院查询学生信息的 depstudents.jsp
Hibernate 的查询语言 HQL 与高级查询

在 WebRoot 下创建 depstudent.jsp 页面, 当进入页面时显示全部的学生信息,
点击选择系院信息后,显示该系院中的学生信息,

<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>
<%@page import="org.sf.entity.Student"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title> 取得并显示所有的学生</title>
</head>
<body>
<jsp:useBean id="stuDao" class="org.sf.dao.impl.StudentDaoImpl"></jsp:useBean>
<jsp:useBean id="depDao" class="org.sf.dao.impl.DepartmentDaoImpl"></jsp:useBean>
<%
String strDepid = request.getParameter("depid");
List<Student> list= null;
if(strDepid==null || strDepid.equals("") || strDepid.equals("0")){ // 查询所有的数据
list = stuDao.getAllStudentList();
}else{
int depid = Integer.parseInt(strDepid);
request.setAttribute("depid", depid);
list = stuDao.getStudentListByDepid(depid);
}
%>
<table align="center" border="1">
<tr>
<td colspan="3" align="center">
<form action="depstudents.jsp">
系院信息:
<select id="depid" name="depid">
<option value="0">-- 请选择--</option>
<c:forEach var="dep" items="${depDao.allDepartmentList}">
<c:choose>
<c:when test="${depid==dep.id}">
<option value="${dep.id}" selected="selected">${dep.mc}</option>
</c:when>
<c:otherwise>
<option value="${dep.id}">${dep.mc}</option>
</c:otherwise>
</c:choose>
</c:forEach>
</select>
<input type="submit" value=" 查询学生 " />
</form>
</td>
</tr>
<tr>
<th> 学号</th>
<th> 姓名</th>
<th> 系院</th>
</tr>
<%
if(list!=null){
for(Student stu:list){
%>
<tr>
<td><%=stu.getStunumber() %></td>
<td><%=stu.getStuname() %></td>
<td><%=stu.getDepartment().getMc() %></td>
</tr>
<%
}
}
%>
</table>
</body>
</html>

下面关于所用到的数据库,实体映射请参考上一篇文章  实体映射

Hibernate 的查询语言 HQL 与高级查询Hibernate 的查询语言 HQL 与高级查询
Hibernate 的查询语言 HQL 与高级查询

Hibernate 的查询语言 HQL 与高级查询

Hibernate 的查询语言 HQL 与高级查询

Hibernate 的查询语言 HQL 与高级查询