SSH(Spring+Struts+Hibernate)框架学习之分页技术的实现

其实在Coding中，有很多东西都是因为需要这么做，然后不会做，去看别人怎么做，然后做一个比别人更华丽的“轮子”。

我这里简单介绍一下自己的分页技术的实现

首先创建一个Page.java的实体类 。

package com.lrms.entity;


/**
 * @author songyx
 *
 */
public class Page {
		private int everyPage;      //每页记录数
		private int totalCount;     //总记录数
		private int totalPage;      //总页数
		private int currentPage;    //当前页码
		private int beginIndex;     //开始的记录数
		private boolean hasPrePage; //是否有上一页
		private boolean hasNextPage;//是否有下一页

		public Page(int everyPage, int totalCount, int totalPage, int currentPage,
				int beginIndex, boolean hasPrePage, boolean hasNextPage) {
			this.everyPage = everyPage;
			this.totalCount = totalCount;
			this.totalPage = totalPage;
			this.currentPage = currentPage;
			this.beginIndex = beginIndex;
			this.hasPrePage = hasPrePage;
			this.hasNextPage = hasNextPage;
		}

		public Page(){}
		
		public int getEveryPage() {
			return everyPage;
		}

		public void setEveryPage(int everyPage) {
			this.everyPage = everyPage;
		}

		public int getTotalCount() {
			return totalCount;
		}

		public void setTotalCount(int totalCount) {
			this.totalCount = totalCount;
		}

		public int getTotalPage() {
			return totalPage;
		}

		public void setTotalPage(int totalPage) {
			this.totalPage = totalPage;
		}

		public int getCurrentPage() {
			return currentPage;
		}

		public void setCurrentPage(int currentPage) {
			this.currentPage = currentPage;
		}

		public int getBeginIndex() {
			return beginIndex;
		}

		public void setBeginIndex(int beginIndex) {
			this.beginIndex = beginIndex;
		}

		public boolean isHasPrePage() {
			return hasPrePage;
		}

		public void setHasPrePage(boolean hasPrePage) {
			this.hasPrePage = hasPrePage;
		}

		public boolean isHasNextPage() {
			return hasNextPage;
		}

		public void setHasNextPage(boolean hasNextPage) {
			this.hasNextPage = hasNextPage;
		}

}

然后创建一个PageUtil.java的工具类

package com.lrms.util;

import com.lrms.entity.Page;

public class PageUtil {
	public static Page createPage(int everyPage,int totalCount,int currentPage) {
		everyPage = getEveryPage(everyPage);
		currentPage = getCurrentPage(currentPage);
		int totalPage = getTotalPage(everyPage, totalCount);
		int beginIndex = getBeginIndex(everyPage, currentPage);
		boolean hasPrePage = getHasPrePage(currentPage);
		boolean hasNextPage = getHasNextPage(totalPage, currentPage);
		return new Page(everyPage, totalCount, totalPage, currentPage,
				beginIndex, hasPrePage,  hasNextPage);
	}
	
	public static Page createPage(Page page,int totalCount) {
		int everyPage = getEveryPage(page.getEveryPage());
		int currentPage = getCurrentPage(page.getCurrentPage());
		int totalPage = getTotalPage(everyPage, totalCount);
		int beginIndex = getBeginIndex(everyPage, currentPage);
		boolean hasPrePage = getHasPrePage(currentPage);
		boolean hasNextPage = getHasNextPage(totalPage, currentPage);
		return new Page(everyPage, totalCount, totalPage, currentPage,
				beginIndex, hasPrePage,  hasNextPage);
	}
	
	//设置每页显示记录数
	public static int getEveryPage(int everyPage) {
		return everyPage == 0 ? 10 : everyPage;
	}
	
	//设置当前页
	public static int getCurrentPage(int currentPage) {
		return currentPage == 0 ? 1 : currentPage;
	}
	
	//设置总页数,需要总记录数，每页显示多少
	public static int getTotalPage(int everyPage,int totalCount) {
		int totalPage = 0;
		if(totalCount % everyPage == 0) {
			totalPage = totalCount / everyPage;
		} else {
			totalPage = totalCount / everyPage + 1;
		}
		return totalPage;
	}
	
	//设置起始点，需要每页显示多少，当前页
	public static int getBeginIndex(int everyPage,int currentPage) {
		return (currentPage - 1) * everyPage;
	}
	
	//设置是否有上一页，需要当前页
	public static boolean getHasPrePage(int currentPage) {
		return currentPage == 1 ? false : true;
	}
	
	//设置是否有下一个，需要总页数和当前页
	public static boolean getHasNextPage(int totalPage, int currentPage) {
		return currentPage == totalPage || totalPage == 0 ? false : true;
	}
}

这两个类就足够我们用的了。我这里以一个实验室的检索为例

实验室的实体类Room

package com.lrms.entity;

/**
 * @author songyx
 *
 */
public class Room {
	private int id;
	private int stuNum;        //容纳人数
	private String name;       //名称
	private String location;   //位置
	private String remark;     //备注
	private int state;         //状态      非持久化字段，数据库里边没有这个字段
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getLocation() {
		return location;
	}
	public void setLocation(String location) {
		this.location = location;
	}
	public String getRemark() {
		return remark;
	}
	public void setRemark(String remark) {
		this.remark = remark;
	}
	public int getStuNum() {
		return stuNum;
	}
	public void setStuNum(int stuNum) {
		this.stuNum = stuNum;
	}
	public int getState() {
		return state;
	}
	public void setState(int state) {
		this.state = state;
	}
	
}

DAO层接口类

package com.lrms.dao;

import java.util.List;

import com.lrms.entity.Page;
import com.lrms.entity.Room;

/**
 * @author songyx
 *
 */
public interface RoomDAO {
	public Room findRoomById(int id);
	public List<Room> queryByPage(final Page page);
	public int roomCounts();
	public void update(Room room);
	public void delete(Room room);
	public void save(Room room);
}

DAO层实现类

package com.lrms.dao.impl;

import java.sql.SQLException;
import java.util.List;

import org.hibernate.HibernateException;
import org.hibernate.Query;
import org.hibernate.Session;
import org.springframework.orm.hibernate3.HibernateCallback;
import org.springframework.orm.hibernate3.support.HibernateDaoSupport;

import com.lrms.dao.RoomDAO;
import com.lrms.entity.Page;
import com.lrms.entity.Room;

/**
 * @author songyx
 *
 */
public class RoomDAOImpl extends HibernateDaoSupport implements RoomDAO{

	@Override
	public Room findRoomById(int id) {
		return this.getHibernateTemplate().get(Room.class, id);
	}

	@SuppressWarnings({ "unchecked", "rawtypes" })
	@Override
	public List<Room> queryByPage(Page page) {
		return (List<Room>)this.getHibernateTemplate().executeFind(new HibernateCallback(){  
            public Object doInHibernate(Session session)  
                    throws HibernateException, SQLException {  
                Query query = session.createQuery("from Room r order by r.id desc");  
                query.setFirstResult(page.getBeginIndex());  
                query.setMaxResults(page.getEveryPage());  
                return query.list();  
            }
        }); 
	}

	@Override
	public int roomCounts() {
		int rowTotal=0;
		rowTotal = ((Long)this.getHibernateTemplate().find("select count(*) from Room").get(0)).intValue();
		return rowTotal;
	}

	@Override
	public void update(Room room) {
		this.getHibernateTemplate().update(room);
	}

	@Override
	public void delete(Room room) {
		this.getHibernateTemplate().delete(room);
	}

	@Override
	public void save(Room room) {
		this.getHibernateTemplate().save(room);
	}
	
}

Service层接口类

package com.lrms.service;

import java.util.List;

import com.lrms.entity.Page;
import com.lrms.entity.Room;

/**
 * @author songyx
 *
 */
public interface RoomService {
	public Room findRoomById(int id);
	public List<Room> queryByPage(final Page page);
	public int roomCounts();
	public void update(Room room);
	public void delete(Room room);
	public void save(Room room);
}

Service层实现类

package com.lrms.service.impl;

import java.util.List;

import com.lrms.dao.RoomDAO;
import com.lrms.entity.Page;
import com.lrms.entity.Room;
import com.lrms.service.RoomService;

/**
 * @author songyx
 *
 */
public class RoomServiceImpl implements RoomService{
	private RoomDAO roomDao;
	
	public RoomDAO getRoomDao() {
		return roomDao;
	}

	public void setRoomDao(RoomDAO roomDao) {
		this.roomDao = roomDao;
	}

	@Override
	public Room findRoomById(int id) {
		return this.getRoomDao().findRoomById(id);
	}

	@Override
	public List<Room> queryByPage(Page page) {
		return this.getRoomDao().queryByPage(page);
	}

	@Override
	public int roomCounts() {
		return this.getRoomDao().roomCounts();
	}

	@Override
	public void update(Room room) {
		this.getRoomDao().update(room);
	}

	@Override
	public void delete(Room room) {
		this.getRoomDao().delete(room);
	}

	@Override
	public void save(Room room) {
		this.getRoomDao().save(room);
	}
	
}

Controller 中的Action写法

package com.lrms.action.room;

import java.util.List;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;

import org.apache.struts2.ServletActionContext;

import com.lrms.entity.Page;
import com.lrms.entity.Room;
import com.lrms.service.RoomService;
import com.lrms.util.PageUtil;
import com.opensymphony.xwork2.ActionSupport;

/**
 * @author songyx
 *
 */
public class ScanRoomAction extends ActionSupport{
	
	private static final long serialVersionUID = 7236063679821783012L;
	private Room room;
	private Page roomPage;
	private int currentPage;
	private RoomService roomService;
	private final int everyPage=10;
	
	public Room getRoom() {
		return room;
	}
	public void setRoom(Room room) {
		this.room = room;
	}
	public Page getRoomPage() {
		return roomPage;
	}
	public void setRoomPage(Page roomPage) {
		this.roomPage = roomPage;
	}
	public int getCurrentPage() {
		return currentPage;
	}
	public void setCurrentPage(int currentPage) {
		this.currentPage = currentPage;
	}
	public RoomService getRoomService() {
		return roomService;
	}
	public void setRoomService(RoomService roomService) {
		this.roomService = roomService;
	}
	public int getEveryPage() {
		return everyPage;
	}
	public String execute(){
		HttpServletRequest request = ServletActionContext.getRequest();
		HttpSession session=request.getSession();
		int totalCount=this.roomService.roomCounts();
		setRoomPage(PageUtil.createPage(everyPage, totalCount, 0));
		List<Room> rooms=this.roomService.queryByPage(roomPage);
		session.setAttribute("rooms", rooms);
		session.setAttribute("roomPage", roomPage);
		
		return SUCCESS;
	}
	public String nextPage(){
		//下一页
		HttpServletRequest request = ServletActionContext.getRequest();
		HttpSession session=request.getSession();
		int totalCount=this.roomService.roomCounts();
		roomPage=PageUtil.createPage(everyPage, totalCount, currentPage+1);
		List<Room> rooms=this.roomService.queryByPage(roomPage);
		session.setAttribute("rooms", rooms);
		session.setAttribute("roomPage", roomPage);
		return "NextPage";
		
	}
	public String frontPage(){
		HttpServletRequest request = ServletActionContext.getRequest();
		HttpSession session=request.getSession();
		int totalCount=this.roomService.roomCounts();
		roomPage=PageUtil.createPage(everyPage, totalCount,currentPage-1);
		List<Room> rooms=this.roomService.queryByPage(roomPage);
		session.setAttribute("rooms", rooms);
		session.setAttribute("roomPage", roomPage);
		return "frontPage";
	}
}

其中通过用户首次查询执行action中的execute方法。方法中首先查询出查询结果的总记录数

int totalCount=this.roomService.roomCounts();

然后创建page对象，我们这里默认的everyPage=10，也就是每页显示的记录数是10，然后通过page对象自动创建page的其他属性值。

然后我们通过page进行查询，就可根据不同的页码、不同的查询条件，得到不同的查询结果。

显示结果的jsp页面源码

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<%
	String path = request.getContextPath();
	int i=0;
%>
<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>实验室管理</title>
    <meta content="IE=edge,chrome=1" http-equiv="X-UA-Compatible">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta name="description" content="">
    <meta name="author" content="">

    <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/lib/bootstrap/css/bootstrap.css">
    <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath}/stylesheets/theme.css">
    <link rel="stylesheet" href="${pageContext.request.contextPath}/lib/font-awesome/css/font-awesome.css">

    <script src="${pageContext.request.contextPath}/lib/jquery-1.8.1.min.js" type="text/javascript"></script>
	<script src="${pageContext.request.contextPath}/javascripts/layer/layer.js" type="text/javascript"></script>
    <!-- Demo page code -->
    
    <style type="text/css">
        #line-chart {
            height:300px;
            width:800px;
            margin: 0px auto;
            margin-top: 1em;
        }
        .brand { font-family: georgia, serif; }
        .brand .first {
            color: #ccc;
            font-style: italic;
        }
        .brand .second {
            color: #fff;
            font-weight: bold;
        }
    </style>
	<script type="text/javascript">
		window.id=0;
		function addRoom(){
			window.location.href='${pageContext.request.contextPath}/admin/addroom.jsp';
		}
		function confirm(id){
			window.id=id;
		}
		function deleteTc()
		{
			$.post("roomservice!delete.action",{'id':window.id},function(result){
				if(result.stateCode==1){
					layer.msg(result.message, {icon: 4});
					window.location.href='scanroom';
				}else{
					layer.msg(result.message, {icon: 2});
				}
			},"json");
		}
	</script>
    <!-- Le HTML5 shim, for IE6-8 support of HTML5 elements -->
    <!--[if lt IE 9]>
      <script src="http://html5shim.googlecode.com/svn/trunk/html5.js"></script>
    <![endif]-->

    <!-- Le fav and touch icons -->
    <link rel="shortcut icon" href="${pageContext.request.contextPath}/assets/ico/favicon.ico">
    <link rel="apple-touch-icon-precomposed" sizes="144x144" href="${pageContext.request.contextPath}/assets/ico/apple-touch-icon-144-precomposed.png">
    <link rel="apple-touch-icon-precomposed" sizes="114x114" href="${pageContext.request.contextPath}/assets/ico/apple-touch-icon-114-precomposed.png">
    <link rel="apple-touch-icon-precomposed" sizes="72x72" href="${pageContext.request.contextPath}/assets/ico/apple-touch-icon-72-precomposed.png">
    <link rel="apple-touch-icon-precomposed" href="${pageContext.request.contextPath}/assets/ico/apple-touch-icon-57-precomposed.png">
  </head>

  <!--[if lt IE 7 ]> <body class="ie ie6"> <![endif]-->
  <!--[if IE 7 ]> <body class="ie ie7"> <![endif]-->
  <!--[if IE 8 ]> <body class="ie ie8"> <![endif]-->
  <!--[if IE 9 ]> <body class="ie ie9"> <![endif]-->
  <!--[if (gt IE 9)|!(IE)]><!--> 
  <body> 
  <!--<![endif]-->
    
    <div class="navbar">
        <div class="navbar-inner">
            <div class="container-fluid">
                <ul class="nav pull-right">
                    
                    <li id="fat-menu" class="dropdown">
                        <a href="#" id="drop3" role="button" class="dropdown-toggle" data-toggle="dropdown">
                            <i class="icon-user"></i> ${user.name}
                            <i class="icon-caret-down"></i>
                        </a>

                        <ul class="dropdown-menu">
                        	<s:if test="#session.user.type==3">
                        		<li><a tabindex="-1" href="adminservice!edit.action?id=<s:property value="#session.user.id" />">个人信息</a></li>
                        	</s:if>
                            <s:elseif test="#session.user.type==2">
                            	<li><a tabindex="-1" href="teacherservice!edit.action?id=<s:property value="#session.user.id" />">个人信息</a></li>
                            </s:elseif>
                            <s:elseif test="#session.user.type==1">
                            	<li><a tabindex="-1" href="studentservice!edit.action?id=<s:property value="#session.user.id" />">个人信息</a></li>
                            </s:elseif>
                            <li class="divider"></li>
                            <li><a tabindex="-1" href="Login!logout.action">注销</a></li>
                        </ul>
                    </li>
                    
                </ul>
                <a class="brand" href="index.jsp"><span class="first">实验室</span> <span class="second">预约管理系统</span></a>
            </div>
        </div>
    </div>
    

    <div class="container-fluid">
        
        <div class="row-fluid">
            <div class="span3">
                <div class="sidebar-nav">
                  <div class="nav-header" data-toggle="collapse" data-target="#dashboard-menu"><i class="icon-dashboard"></i>预约管理</div>
                    <ul id="dashboard-menu" class="nav nav-list collapse in">
                        <s:if test="#session.user.type==3">
                        	<li><a href="scancourse?type=2">未审核预约</a></li>
                        	<li><a href="scancourse?type=0">预约记录</a></li>
                        </s:if>
                        <s:if test="#session.user.type==1">
                        	<li><a href="courseservice!book.action">预约</a></li>
                        	<li><a href="scancourse?type=0">预约记录</a></li>
                        </s:if>
                        <s:if test="#session.user.type==2">
                     
                        	<li><a href="scancourse?type=0">预约记录</a></li>
                        </s:if>
                    </ul>
                <div class="nav-header" data-toggle="collapse" data-target="#accounts-menu"><i class="icon-briefcase"></i>查看课表</div>
                <ul id="accounts-menu" class="nav nav-list collapse in">
                  <li ><a href="scancourse?type=1">查看课表</a></li>
                </ul>
                <s:if test="#session.user.type!=1">
				<div class="nav-header" data-toggle="collapse" data-target="#account-menu"><i class="icon-briefcase"></i>人员管理</div>
                <ul id="account-menu" class="nav nav-list collapse in">
                  <s:if test="#session.user.type==3">
                  	<li ><a href="${pageContext.request.contextPath}/admin/addadmin.jsp">增加管理员</a></li>
                  	<li ><a href="scanadmin">管理员管理</a></li>
                  	<li ><a href="${pageContext.request.contextPath}/admin/addteacher.jsp">增加教师</a></li>
                  	<li ><a href="scanteacher">教师管理</a></li>
                  </s:if>
                  <s:if test="#session.user.type==2">
                  	<li ><a href="studentservice!edit.action">设置课代表</a></li>
                  </s:if>
                  <li ><a href="scanstudent">查看课代表</a></li>
                </ul>
                </s:if>
                 <s:if test="#session.user.type==3">
                <div class="nav-header" data-toggle="collapse" data-target="#settings-menu"><i class="icon-exclamation-sign"></i>实验室管理</div>
                <ul id="settings-menu" class="nav nav-list collapse in">
                  <li ><a href="scanroom">实验室管理</a></li>
	              <li ><a href="${pageContext.request.contextPath}/admin/addroom.jsp">添加实验室</a></li>
                </ul>
                </s:if>
            </div>
            
        </div>
        <div class="span9">
            <h1 class="page-title">实验室管理</h1>
<div class="btn-toolbar">
    <s:if test="#session.user.type==3">
    <button class="btn btn-primary" onclick="addRoom();"><i class="icon-plus"></i> 增加实验室</button>
  	</s:if>
  <div class="btn-group">
  </div>
</div>
<div class="well">
    <table class="table">
      <thead>
        <tr>
          <th>#</th>
          <th>实验室名称</th>
          <th>位置</th>
          <th>容纳人数</th>
          <th>备注</th>
          <th style="width: 26px;"></th>
        </tr>
      </thead>
      <tbody>
      	<s:iterator value="#session.rooms" id="infos">
      		<tr>
	      		<td><%=++i%></td>
	      		<td><a href="roomservice!edit.action?id=<s:property value="#infos.id" />"><s:property value="#infos.name" /></a></td>
				<td><s:property value="#infos.location" /></td>
				<td><s:property value="#infos.stuNum" /></td>
	          	<td><s:property value="#infos.remark" /></td>
	          	<s:if test="#session.user.type==3">
	          	<td>
		            <a href="roomservice!edit.action?id=<s:property value="#infos.id" />"><i class="icon-pencil"></i></a>
		            <a href="#myModal" role="button" data-toggle="modal" onclick="confirm(<s:property value="#infos.id" />)"><i class="icon-remove"></i></a>
		        </td>
		        </s:if>
			</tr>
		</s:iterator>
      </tbody>
    </table>
</div>
<div class="pagination">
    <ul>
		<s:if test="#request.roomPage.hasPrePage==true">
		<li><a href="scanroom!frontPage.action?currentPage=<s:property value="roomPage.currentPage" />" class="btu">上一页</a></li>
		</s:if>
		<li><a href="#" class="btu active"><s:property value="roomPage.currentPage" /></a></li>
		<s:if test="#request.roomPage.currentPage+1<=#request.roomPage.totalPage">
		<li><a href="scanroom!nextPage.action?currentPage=<s:property value="roomPage.currentPage" />" class="btu"><s:property value="roomPage.currentPage+1" /></a></li>
		</s:if>
		<s:if test="#request.roomPage.currentPage+2<=#request.roomPage.totalPage">
		<li><a href="scanroom!nextPage.action?currentPage=<s:property value="roomPage.currentPage+1" />" class="btu"><s:property value="roomPage.currentPage+2" /></a></li>
		</s:if>
		<s:if test="#request.roomPage.currentPage+3<=#request.roomPage.totalPage">
		<li><a href="scanroom!nextPage.action?currentPage=<s:property value="roomPage.currentPage+2" />" class="btu"><s:property value="roomPage.currentPage+3" /></a></li>
		</s:if>
		<s:if test="#request.roomPage.hasNextPage==true">
		<li><a href="scanroom!nextPage.action?currentPage=<s:property value="roomPage.currentPage" />" class="btu">下一页</a></li>
		</s:if>
    </ul>
</div>

<div class="modal small hide fade" id="myModal" tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true">
    <div class="modal-header">
        <button type="button" class="close" data-dismiss="modal" aria-hidden="true">×</button>
        <h3 id="myModalLabel">警告</h3>
    </div>
    <div class="modal-body">
        <p class="error-text"><i class="icon-warning-sign modal-icon"></i>确定要删除这条信息吗?</p>
    </div>
    <div class="modal-footer">
        <button class="btn" data-dismiss="modal" aria-hidden="true">取消</button>
        <button class="btn btn-danger" data-dismiss="modal" onclick="deleteTc();">确定</button>
    </div>
</div>

        </div>
    </div>
	</div>
   <footer>
        <hr>
        <p class="pull-right">Copyright <a title="内蒙古大学" target="_blank">内蒙古大学</a></p>
        <p>&copy; 2017 <a>内蒙古大学</a></p>
    </footer>
    <script src="${pageContext.request.contextPath}/lib/bootstrap/js/bootstrap.js"></script>

  </body>
</html>

显示结果：