JAVA分页原理（三）——使用Hibernate实现

最新推荐文章于 2021-02-24 01:31:21 发布

原创最新推荐文章于 2021-02-24 01:31:21 发布 · 306 阅读

1 ·

CC 4.0 BY-SA版权

本文介绍了一个基于Hibernate技术的Java应用案例，实现了一个简单的分页查询功能，并通过前端页面的交互展示了下拉加载更多数据的效果。

hibernate.cfg.xml：

<!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">com.mysql.jdbc.Driver</property>
		<property name="connection.url">jdbc:mysql://127.0.0.1:3306/demo</property>
		<property name="connection.username">root</property>
		<property name="connection.password">1234</property>
		
		<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
		
		<!-- 是否在控制台打印sql语句，true打印，false不打印 -->
		<property name="show_sql">true</property>
		<!-- 将sql语句格式化再打印 ,格式化了反而不好阅读 <property name="hibernate.format_sql">true</property> -->
  
  		<mapping class="com.imooc.page.model.Student"/>
	</session-factory>
</hibernate-configuration>

Student.java

package com.imooc.page.model;

import java.io.Serializable;
import java.util.Map;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;

import org.hibernate.annotations.GenericGenerator;



@Entity
@Table(name = "t_student")
public class Student implements Serializable {

	private static final long serialVersionUID = -7476381137287496245L;
	
	private int id;
	
	private String stuName;

	private int age;
	
	private int gender;
	
	private String address;
	
	public Student() {
		super();
	}

	public Student(int id, String stuName, int age, int gender, String address) {
		super();
		this.id = id;
		this.stuName = stuName;
		this.age = age;
		this.gender = gender;
		this.address = address;
	}

	public Student(Map<String,Object> map){
		this.id = (int)map.get("id");
		this.stuName = (String)map.get("stu_name");
		this.age = (int)map.get("age");
		this.gender = (int)map.get("gender");
		this.address = (String)map.get("address");
	}
	
	@Id
	@GeneratedValue(generator = "increment")
	@GenericGenerator(name = "increment",strategy = "increment")
	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}

	@Column(name = "stu_name")
	public String getStuName() {
		return stuName;
	}

	public void setStuName(String stuName) {
		this.stuName = stuName;
	}

	@Column(name = "age")
	public int getAge() {
		return age;
	}

	public void setAge(int age) {
		this.age = age;
	}

	@Column(name = "gender")
	public int getGender() {
		return gender;
	}

	public void setGender(int gender) {
		this.gender = gender;
	}

	@Column(name = "address")
	public String getAddress() {
		return address;
	}

	public void setAddress(String address) {
		this.address = address;
	}

	@Override
	public String toString() {
		return "Student [id=" + id + ", stuName=" + stuName + ", age=" + age + ", gender=" + gender + ", address="
				+ address + "]";
	}

}

package com.imooc.page;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;
import org.hibernate.cfg.Configuration;
import org.hibernate.service.ServiceRegistry;

public class HibernateSessionFactory {

	private static final ThreadLocal<Session> threadLocal = new ThreadLocal<Session>();
	private static org.hibernate.SessionFactory sessionFactory;
	
	private static Configuration configuration = new Configuration();
	private static ServiceRegistry serviceRegistry;
	
	static{
		try{
			configuration.configure();
//			serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
			sessionFactory = configuration.buildSessionFactory();
		}catch(Exception e){
			System.err.println("%%%% Error Creating SessionFactory %%%%");
			e.printStackTrace();
		}
	}
	private HibernateSessionFactory(){
		
	}
	
	public static Session getSession() throws HibernateException{
		Session session = (Session)threadLocal.get();
		
		if(session==null||!session.isOpen()){
			if(sessionFactory==null){
				rebuildSessionFactory();
			}
			session = (sessionFactory!=null)?sessionFactory.openSession():null;
			threadLocal.set(session);
		}
		return session;
	}
	
	public static void rebuildSessionFactory(){
		try{
			configuration.configure();
//			serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
			sessionFactory = configuration.buildSessionFactory();
		}catch(Exception e){
			System.err.println("%%%% Error Creating SessionFactory %%%%");
			e.printStackTrace();
		}
	}
	
	public static void closeSession() throws HibernateException{
		Session session = (Session)threadLocal.get();
		threadLocal.set(null);
		
		if(session!=null){
			session.close();
		}
	}
}

HibernateStudentDaoImpl.java

package com.imooc.page.dao;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

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

import com.imooc.page.Constant;
import com.imooc.page.HibernateSessionFactory;
import com.imooc.page.model.Pager;
import com.imooc.page.model.Student;

public class HibernateStudentDaoImpl implements StudentDao {

	@SuppressWarnings("unchecked")
	@Override
	public Pager<Student> findStudent(Student searchModel, int pageNum, int pageSize) {
		Pager<Student> result = null;
		//存放查询参数
		Map<String,Object> paramMap = new HashMap<String,Object>();
		String stuName = searchModel.getStuName();
		int gender = searchModel.getGender();
		
		StringBuilder hql = new StringBuilder("from Student where 1=1");
		StringBuilder countHql = new StringBuilder("select count(id) from Student where 1=1");
		if(stuName !=null&&!stuName.equals("")){
			hql.append(" and stuName like :stuName");
			countHql.append(" and stuName like :stuName");
			paramMap.put("stuName", "%"+stuName+"%");
		}
		if(gender==Constant.GENDER_FEMALE||gender==Constant.GENDER_MALE){
			hql.append(" and gender = :gender");
			countHql.append(" and gender = :gender");
			paramMap.put("gender",gender);
		}
		// 起始索引
		int fromIndex = pageSize * (pageNum - 1);
		
		//存放所有查询出的学生对象
		List<Student> studentList = new ArrayList<Student>();
		
		Session session = null;
		try {
			session = HibernateSessionFactory.getSession();
			//获取query对象
			Query hqlQuery = session.createQuery(hql.toString());
			Query countHqlQuery = session.createQuery(countHql.toString());
			
			//设置查询参数
			setQueryParams(hqlQuery,paramMap);
			setQueryParams(countHqlQuery,paramMap);
			//从第几条记录开始查询
			hqlQuery.setFirstResult(fromIndex);
			
			//每页显示多少条记录
			hqlQuery.setMaxResults(pageSize);
			//获取查询结果
			studentList = hqlQuery.list();
			//获取总记录条数
			List<?> countResult = countHqlQuery.list();
			int totalRecord = ((Number)countResult.get(0)).intValue();
		
			// 获取总页数
			int totalPage = totalRecord / pageSize;
			if (totalRecord % pageSize != 0) {
				totalPage = totalPage + 1;
			}
			//组装pager对象
			result = new Pager<>(pageSize, pageNum, totalRecord, totalPage, studentList);
		} catch (Exception e) {
			throw new RuntimeException("查询所有数据异常！",e);
		}finally{
			if(session != null){
				HibernateSessionFactory.closeSession();
			}
		}
		return result;
	}

	/**
	 * 设置查询的参数
	 * @param query
	 * @param paramMap
	 * @return
	 */
	private Query setQueryParams(Query query,Map<String,Object> paramMap){
		if(paramMap!=null&&!paramMap.isEmpty()){
			for(Map.Entry<String, Object> param:paramMap.entrySet()){
				query.setParameter(param.getKey(), param.getValue());
			}
		}
		return query;
	}

}

HibernateStudentServiceImpl.java

package com.imooc.page.service;

import com.imooc.page.dao.HibernateStudentDaoImpl;
import com.imooc.page.dao.StudentDao;
import com.imooc.page.model.Pager;
import com.imooc.page.model.Student;

public class HibernateStudentServiceImpl implements StudentService {

	private StudentDao studentDao;
	
	public HibernateStudentServiceImpl(){
		//创建service实现类时，初始化dao对象
		studentDao = new HibernateStudentDaoImpl();
	}
	@Override
	public Pager<Student> findStudent(Student searchModel, int pageNum, int pageSize) {
		Pager<Student> result = studentDao.findStudent(searchModel, pageNum, pageSize);
		return result;
	}
	public StudentDao getStudentDao() {
		return studentDao;
	}
	public void setStudentDao(StudentDao studentDao) {
		this.studentDao = studentDao;
	}

}

HibernateServlet.java

package com.imooc.page.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class HibernateServlet extends HttpServlet {
	
	private static final long serialVersionUID = -4873699362194465829L;
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.getRequestDispatcher("hibernateStudent.jsp").forward(request, response);
	}

}

HibernateDataServlet.java:

package com.imooc.page.servlet;

import java.io.IOException;
import java.io.Writer;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.alibaba.fastjson.JSON;
import com.imooc.page.Constant;
import com.imooc.page.model.Pager;
import com.imooc.page.model.Student;
import com.imooc.page.service.HibernateStudentServiceImpl;
import com.imooc.page.service.StudentService;


public class HibernateDataServlet extends HttpServlet {
	
	private static final long serialVersionUID = -4873699362194465829L;
	private StudentService studentService = new HibernateStudentServiceImpl();
	
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		doPost(request, response);
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		//接收request里的参数
		String stuName = request.getParameter("stuName");
		
		int gender = Constant.DEFAULT_GENDER;
		String genderStr = request.getParameter("gender");
		if(genderStr!=null&&!"".equals(genderStr.trim())){
			gender = Integer.parseInt(genderStr);
		}
		String pageNumStr = request.getParameter("pageNum");
		int pageNum = Constant.DEFAULT_PAGE_NUM;
		
		if(pageNumStr!=null&&!"".equals(pageNumStr.trim())){
			pageNum = Integer.parseInt(pageNumStr);
		}
		
		int pageSize = Constant.DEFAULT_PAGE_SIZE;
		String pageSizeStr = request.getParameter("pageSize");
		if(pageSizeStr!=null&&!"".equals(pageSizeStr.trim())){
			pageSize = Integer.parseInt(pageSizeStr);
		}
		//组装查询条件
		Student searchModel = new Student();
		searchModel.setStuName(stuName);
		searchModel.setGender(gender);
		//调用service获取查询结果
		Pager<Student> result = studentService.findStudent(searchModel, pageNum, pageSize);
		//不使用缓存
		response.setHeader("Cache-Control", "no-cache");
		response.setHeader("Pragma", "no-cache");
		//设置超时时间为0
		response.addDateHeader("Expires", 0);
		//设置编码格式为utf-8
		response.setContentType("text/html;charset=utf-8");
		//获取查询数据的json格式
		String responseStr = JSON.toJSONString(result);
		
		Writer writer = response.getWriter();
		writer.write(responseStr);
		writer.flush();
	}

}

hibernateStudent.jsp

<%@ page language="java" import="java.util.*"
	contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>学生信息</title>
</head>
<%
	//获取请求上下文
	String context = request.getContextPath();
%>
<link href="../css/pagination.css" rel="stylesheet" type="text/css"/>
<script type="text/javascript" src="../js/jquery-1.11.3.js"></script>
<script type="text/javascript" src="../js/jquery.pagination.js"></script>
<script type="text/javascript">
//第一步：页面渲染完之后，请求后台，获取学生数据，加载学生信息
//第二步：完成学生查询功能
//第三步：下拉加载更多数据的功能

var url = "<%=context%>/hibernate/HibernateDataServlet"; //请求获取数据的url
var totalPage = 1;//一共有多少条数据
var pageSize = 30;//每页显示多少条数据
var currentPage = 1;//当前第几页数据，默认为1
var isLoading = false;//标识是否正在加载更多的数据
//页面渲染完之后执行的代码
$(function(){
	//绑定事件，监听滚动条下拉的动作
	bindScrollEvent();
	//请求后台，加载学生信息
	 queryStudent(1);
});

function queryForm(){
	//绑定事件，监听滚动条下拉的动作
	bindScrollEvent();
	//清空学生的数据
	$("#studentDataBody").html("");
	//清空学生为空的提示信息
	$("#emptyInfo").html("");
	//查询学生
	queryStudent(1);
}
//请求后台，加载学生信息
function queryStudent(pageNum){
	if(pageNum>totalPage){
		$("#emptyInfo").html("没有更多的学生数据了……");
		$(window).unbind("scroll");
	}
	if(isLoading){
		return;
	}else{
		isLoading = true;//修改状态为正在加载数据
	}
	var stuName = $("#stu_name").val();//获取学生姓名
	var gender = $("#gender").val();//获取学生姓名
	//进行post请求
	$.post(url,{"pageSize":pageSize,"pageNum":pageNum,"stuName":stuName,"gender":gender},function(data){
		//加载学生信息 
		totalPage = data.totalPage;//一共有多少条数据
		currentPage = data.currentPage;//获取当前第几页数据
		var studentList = data.dataList;//学生记录信息
		if(totalPage==0){
			$("#emptyInfo").html("没有更多的学生数据了……");
		}
		//加载学生的数据
		showStudentData(studentList);
		isLoading = false;
	},"json")
}
//加载学生的数据
function showStudentData(studentList){
	var studentDataHtml = "";
	$.each(studentList,function(idx,obj){
		studentDataHtml += "<tr>";
		studentDataHtml += "<td>"+obj.stuName+"</td>";//获取学生姓名的值
		if(obj.gender==1){
			studentDataHtml += "<td>男</td>";//获取学生性别的值
		}else{
			studentDataHtml += "<td>女</td>";//获取学生性别的值
		}
		studentDataHtml += "<td>"+obj.age+"</td>";//获取学生年龄的值
		studentDataHtml += "<td>"+obj.address+"</td>";//获取学生家庭住址的值
		studentDataHtml += "</tr>";
	});
	$("#studentDataBody").append(studentDataHtml);
}

function bindScrollEvent(){
	//添加滚动监听事件
	$(window).scroll(function(){
		var docHeight = $(document).height();//获取整个页面的高度
		var winHeight = $(window).height();//获取当前窗体的高度
		var winScrollHeight = $(window).scrollTop();//获取滚动条滚动的距离
		if(docHeight-30<=winHeight+winScrollHeight){//滚动条到底
			//加载更多的学生数据
			queryStudent(currentPage+1);
		}
	});
}
</script>
<body>
	<div style="margin-left: 100px; margin-top: 100px;">
		<div>
			<font color="red">${errorMsg }</font>
		</div>
		<div>
			<form action="#" id="stuForm"
				method="post">
				姓名 <input type="text" name="stuName" id="stu_name"  value="${stuName }"
					style="width: 120px;"> &nbsp; 性别 <select name="gender"
					id="gender" style="width: 80px">
					<option value="0">全部</option>
					<option value="1">男</option>
					<option value="2">女</option>
				</select> &nbsp;&nbsp; 
				<input type="button" value="查询" onclick="queryForm()">
			</form>
		</div>
		<br> 学生信息列表：<br> <br>
			<table border="1px" cellspacing="0px"
				style="border-collapse: collapse" id="studentTable">
				<thead>
					<tr height="30">
						<th width="130">姓名</th>
						<th width="130">性别</th>
						<th width="130">年龄</th>
						<th width="130">家庭地址</th>
					</tr>
				</thead>
				<tbody id="studentDataBody">
				</tbody>
			</table>
			<div id="emptyInfo"></div>
			<br>
	</div>
</body>
</html>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>pager</display-name>
  <servlet>
  	<servlet-name>SublistServlet</servlet-name>
  	<servlet-class>com.imooc.page.servlet.SublistServlet</servlet-class>
  </servlet>
  
  <servlet-mapping>
  	<servlet-name>SublistServlet</servlet-name>
  	<url-pattern>/sublist/SublistServlet</url-pattern>
  </servlet-mapping>
  
   <servlet>
  	<servlet-name>JdbcSqlServlet</servlet-name>
  	<servlet-class>com.imooc.page.servlet.JdbcSqlServlet</servlet-class>
  </servlet>
  
  <servlet-mapping>
  	<servlet-name>JdbcSqlServlet</servlet-name>
  	<url-pattern>/jdbcSql/JdbcSqlServlet</url-pattern>
  </servlet-mapping>
  
  <servlet>
  	<servlet-name>HibernateServlet</servlet-name>
  	<servlet-class>com.imooc.page.servlet.HibernateServlet</servlet-class>
  </servlet>
  
  <servlet-mapping>
  	<servlet-name>HibernateServlet</servlet-name>
  	<url-pattern>/hibernate/HibernateServlet</url-pattern>
  </servlet-mapping>
  
  <servlet>
  	<servlet-name>HibernateDataServlet</servlet-name>
  	<servlet-class>com.imooc.page.servlet.HibernateDataServlet</servlet-class>
  </servlet>
  
  <servlet-mapping>
  	<servlet-name>HibernateDataServlet</servlet-name>
  	<url-pattern>/hibernate/HibernateDataServlet</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
</web-app>

这样，就实现了下拉加载更多数据的功能。