关于在SSM框架下使用PageHelper
Posted loki-dong
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很长一段时间里，我学习编程很少总结代码。后来代码总结也只是写在一个电脑里的文件夹，觉得与互联网脱轨了，哈哈哈，所以现在也准备写一写博客，记录自己，提高水平。
这是我的第一篇，也是关于SSM框架下使用PageHelper。
这里不具体写我做的项目课题的全部内容，主要专注于PageHelper部分
工程结构如下图：
首先在pom.xml（parking_dao模块下）引入PageHelper依赖
1 <?xml version="1.0" encoding="UTF-8"?> 2 <project xmlns="http://maven.apache.org/POM/4.0.0" 3 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 4 xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> 5 <parent> 6 <artifactId>parking</artifactId> 7 <groupId>com.dong</groupId> 8 <version>1.0-SNAPSHOT</version> 9 </parent> 10 <modelVersion>4.0.0</modelVersion> 11 12 <artifactId>parking_dao</artifactId> 13 <dependencies> 14 <dependency> 15 <groupId>mysql</groupId> 16 <artifactId>mysql-connector-java</artifactId> 17 <version>5.1.47</version> 18 </dependency> 19 <dependency> 20 <groupId>org.mybatis</groupId> 21 <artifactId>mybatis</artifactId> 22 <version>3.4.6</version> 23 </dependency> 24 25 <dependency> 26 <groupId>org.springframework</groupId> 27 <artifactId>spring-core</artifactId> 28 <version>$spring.version</version> 29 </dependency> 30 <dependency> 31 <groupId>org.springframework</groupId> 32 <artifactId>spring-context</artifactId> 33 <version>$spring.version</version> 34 </dependency> 35 <dependency> 36 <groupId>org.springframework</groupId> 37 <artifactId>spring-beans</artifactId> 38 <version>$spring.version</version> 39 </dependency> 40 <dependency> 41 <groupId>org.mybatis</groupId> 42 <artifactId>mybatis-spring</artifactId> 43 <version>1.3.1</version> 44 </dependency> 45 <dependency> 46 <groupId>org.springframework</groupId> 47 <artifactId>spring-jdbc</artifactId> 48 <version>$spring.version</version> 49 </dependency> 50 <dependency> 51 <groupId>com.github.pagehelper</groupId> 52 <artifactId>pagehelper</artifactId> 53 <version>5.1.2</version> 54 </dependency> 55 </dependencies> 56 57 </project>
最主要的是：
<dependency>
<groupId>com.github.pagehelper</groupId>
<artifactId>pagehelper</artifactId>
<version>5.1.2</version>
</dependency>
随后需要在spring配置（spring-dao）文件里配置PageHelper
1 <beans xmlns="http://www.springframework.org/schema/beans" 2 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 3 xmlns:context="http://www.springframework.org/schema/context" 4 xsi:schemaLocation="http://www.springframework.org/schema/beans 5 http://www.springframework.org/schema/beans/spring-beans.xsd 6 http://www.springframework.org/schema/context 7 http://www.springframework.org/schema/context/spring-context.xsd"> 8 9 <context:component-scan base-package="com.dong.parking.dao"/> 10 11 <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> 12 <property name="driverClassName" value="com.mysql.jdbc.Driver"/> 13 <property name="url" 14 value="jdbc:mysql://localhost:3306/car_park?useUnicode=true&characterEncoding=utf-8&useSSL=false"/> 15 <property name="username" value="root"/> 16 <property name="password" value="root"/> 17 </bean> 18 19 <bean id="sessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> 20 <property name="typeAliasesPackage" value="com.dong.parking.entity"/> 21 <property name="dataSource" ref="dataSource"/> 22 <!--配置PageHelper--> 23 <property name="plugins"> 24 <array> 25 <bean class="com.github.pagehelper.PageInterceptor"> 26 <property name="properties"> 27 <value> 28 offsetAsPageNum=true 29 rowBoundsWithCount=true 30 pageSizeZero=true 31 reasonable=true 32 </value> 33 </property> 34 </bean> 35 </array> 36 </property> 37 </bean> 38 <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> 39 <property name="sqlSessionFactoryBeanName" value="sessionFactory"/> 40 <property name="basePackage" value="com.dong.parking.dao"/> 41 </bean> 42 </beans>
最主要的为：
1 <bean id="sessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean"> 2 <property name="typeAliasesPackage" value="com.dong.parking.entity"/> 3 <property name="dataSource" ref="dataSource"/> 4 <!--配置PageHelper--> 5 <property name="plugins"> 6 <array> 7 <bean class="com.github.pagehelper.PageInterceptor"> 8 <property name="properties"> 9 <value> 10 offsetAsPageNum=true 11 rowBoundsWithCount=true 12 pageSizeZero=true 13 reasonable=true 14 </value> 15 </property> 16 </bean> 17 </array> 18 </property> 19 </bean>
Ok，关于配置已经好了，现在进入parking，结构如下，以红框标识的为例
ParkSpaceController代码如下
1 package com.dong.parking.controller; 2 3 import com.dong.parking.biz.ParkSpaceBiz; 4 import com.dong.parking.entity.ParkSpace; 5 import com.dong.parking.entity.User; 6 import com.dong.parking.global.Constant; 7 import com.github.pagehelper.Page; 8 import com.github.pagehelper.PageHelper; 9 import com.github.pagehelper.PageInfo; 10 import org.springframework.beans.factory.annotation.Autowired; 11 import org.springframework.stereotype.Controller; 12 import org.springframework.web.bind.annotation.RequestMapping; 13 import org.springframework.web.bind.annotation.RequestParam; 14 15 import javax.servlet.http.HttpSession; 16 import java.util.List; 17 import java.util.Map; 18 19 @Controller("parkSpaceController") 20 @RequestMapping("/parkSpace") 21 public class ParkSpaceController 22 @Autowired 23 private ParkSpaceBiz parkSpaceBiz; 24 25 @RequestMapping(value = "/list") 26 public String list(Map<String, Object> map, @RequestParam(value = "status", required = false) Integer status, 27 @RequestParam(defaultValue = "1", required = true, value = "pageNo") Integer pageNo) 28 List<ParkSpace> list = null; 29 Integer pageSize = 2; 30 PageHelper.startPage(pageNo, pageSize); 31 if (status == null) 32 list = parkSpaceBiz.findAll(); 33 else 34 list = parkSpaceBiz.findByStatus(status); 35 36 37 PageInfo<ParkSpace> pageInfo = new PageInfo<ParkSpace>(list); 38 map.put("pageInfo", pageInfo); 39 return "park_space_list"; 40 41 42 @RequestMapping("/to_update") 43 public String toUpdate(Map<String, Object> map, @RequestParam int id) 44 map.put("floor", Constant.getFloor()); 45 map.put("area", Constant.getArea()); 46 map.put("parkSpace", parkSpaceBiz.findById(id)); 47 return "park_space_update"; 48 49 50 @RequestMapping("/update") 51 public String update(ParkSpace parkSpace, HttpSession session) 52 User user = (User) session.getAttribute("user"); 53 parkSpace.setUpdateBy(user.getSn()); 54 parkSpaceBiz.edit(parkSpace); 55 return "redirect:list"; 56 57 58 59 @RequestMapping("/to_add") 60 public String toAdd(Map<String, Object> map) 61 map.put("floor", Constant.getFloor()); 62 map.put("area", Constant.getArea()); 63 map.put("parkSpace", new ParkSpace()); 64 return "park_space_add"; 65 66 67 @RequestMapping("/add") 68 public String add(ParkSpace parkSpace, HttpSession session) 69 User user = (User) session.getAttribute("user"); 70 parkSpace.setCreateBy(user.getSn()); 71 parkSpace.setUpdateBy(user.getSn()); 72 parkSpaceBiz.add(parkSpace); 73 return "redirect:list"; 74 75 76 77 @RequestMapping(value = "/remove", params = "id") 78 public String remove(int id) 79 parkSpaceBiz.remove(id); 80 return "redirect:list"; 81 82
我们关注一下list方法
1 @RequestMapping(value = "/list") 2 public String list(Map<String, Object> map, @RequestParam(value = "status", required = false) Integer status, 3 @RequestParam(defaultValue = "1", required = true, value = "pageNo") Integer pageNo) 4 List<ParkSpace> list = null; 5 Integer pageSize = 2; 6 PageHelper.startPage(pageNo, pageSize); 7 if (status == null) 8 list = parkSpaceBiz.findAll(); 9 else 10 list = parkSpaceBiz.findByStatus(status); 11 12 13 PageInfo<ParkSpace> pageInfo = new PageInfo<ParkSpace>(list); 14 map.put("pageInfo", pageInfo); 15 return "park_space_list"; 16
这里的形参pageNo为前台传来的值。这里的步骤可归结如下
步骤1：PageHelper.startPage(pageNo,pageSize)，设置每页显示的个数和页数
步骤2：List<Bean> list = beanService.find(),获得bean的结合(这里以Bean代表一般的实体类)
步骤3：PageInfo<Bean> pageInfo = new PageInfo<Bean>(list); 将list集合封装到pageInfo对象。
步骤4：map.put("pageInfo",pageInfo);将pageInfo对象回给前台
好了，现在咱们来到前台页面，park_space_list.jsp代码如下
1 <%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> 2 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 3 4 <jsp:include page="top.jsp"/> 5 6 <section id="content" class="table-layout animated fadeIn"> 7 <div class="tray tray-center"> 8 <div class="content-header"> 9 <h2> 员工列表 </h2> 10 <p class="lead"></p> 11 </div> 12 <div class="admin-form theme-primary mw1000 center-block" style="padding-bottom: 175px;"> 13 <div class="panel heading-border"> 14 <div class="panel-menu"> 15 <div class="row"> 16 <div class="hidden-xs hidden-sm col-md-3"> 17 <div class="btn-group"> 18 <button type="button" class="btn btn-default light"> 19 <i class="fa fa-refresh"></i> 20 </button> 21 <button type="button" class="btn btn-default light"> 22 <i class="fa fa-trash"></i> 23 </button> 24 <button type="button" class="btn btn-default light"> 25 <i class="fa fa-plus" 26 onclick="javascript:window.location.href=‘/parkSpace/to_add‘;"></i> 27 </button> 28 </div> 29 </div> 30 <div class="col-xs-12 col-md-9 text-right"> 31 <div class="btn-group"> 32 <button type="button" class="btn btn-default light"> 33 <i class="fa fa-chevron-left"></i> 34 </button> 35 36 <button type="button" class="btn btn-default light"> 37 <i class="fa fa-chevron-right"></i> 38 </button> 39 </div> 40 </div> 41 </div> 42 </div> 43 <div class="panel-body pn"> 44 <table id="message-table" class="table admin-form theme-warning tc-checkbox-1"> 45 <thead> 46 <tr class=""> 47 <th class="text-center hidden-xs">Select</th> 48 <th class="hidden-xs">楼层</th> 49 <th class="hidden-xs">区域</th> 50 <th class="hidden-xs">车位号</th> 51 <th class="hidden-xs">状态</th> 52 53 <th>操作</th> 54 </tr> 55 </thead> 56 <tbody> 57 <c:forEach items="$pageInfo.list" var="space"> 58 <tr class="message-unread"> 59 <td class="hidden-xs"> 60 <label class="option block mn"> 61 <input type="checkbox" name="mobileos" value="FR"> 62 <span class="checkbox mn"></span> 63 </label> 64 </td> 65 <td>$space.floor</td> 66 <td>$space.area</td> 67 <td>$space.spaceId</td> 68 <td> 69 <c:if test="$space.status == 0">空闲</c:if> 70 <c:if test="$space.status == 1">占用</c:if> 71 <c:if test="$space.status == 2">预定</c:if> 72 </td> 73 74 <td> 75 <a href="/parkSpace/to_update?id=$space.id">编辑</a> 76 <a href="/parkSpace/remove?id=$space.id">删除</a> 77 </td> 78 </tr> 79 </c:forEach> 80 </tbody> 81 </table> 82 <p>当前 $pageInfo.pageNum 页,总$pageInfo.pages 83 页,总 $pageInfo.total 条记录 84 </p> 85 <a href="list?pageNo=$pageInfo.getFirstPage()">首页</a> 86 <c:if test="$pageInfo.hasPreviousPage "> 87 <a href="list?pageNo=$pageInfo.pageNum-1">上一页</a> 88 </c:if> 89 90 <c:if test="$pageInfo.hasNextPage "> 91 <a href="list?pageNo=$pageInfo.pageNum+1">下一页</a> 92 </c:if> 93 94 <a href="list?pageNo=$pageInfo.getLastPage()">末页</a> 95 </div> 96 </div> 97 </div> 98 </div> 99 </section> 100 101 <jsp:include page="bottom.jsp"/>
我们关注于
1 <div class="panel-body pn"> 2 <table id="message-table" class="table admin-form theme-warning tc-checkbox-1"> 3 <thead> 4 <tr class=""> 5 <th class="text-center hidden-xs">Select</th> 6 <th class="hidden-xs">楼层</th> 7 <th class="hidden-xs">区域</th> 8 <th class="hidden-xs">车位号</th> 9 <th class="hidden-xs">状态</th> 10 11 <th>操作</th> 12 </tr> 13 </thead> 14 <tbody> 15 <c:forEach items="$pageInfo.list" var="space"> 16 <tr class="message-unread"> 17 <td class="hidden-xs"> 18 <label class="option block mn"> 19 <input type="checkbox" name="mobileos" value="FR"> 20 <span class="checkbox mn"></span> 21 </label> 22 </td> 23 <td>$space.floor</td> 24 <td>$space.area</td> 25 <td>$space.spaceId</td> 26 <td> 27 <c:if test="$space.status == 0">空闲</c:if> 28 <c:if test="$space.status == 1">占用</c:if> 29 <c:if test="$space.status == 2">预定</c:if> 30 </td> 31 32 <td> 33 <a href="/parkSpace/to_update?id=$space.id">编辑</a> 34 <a href="/parkSpace/remove?id=$space.id">删除</a> 35 </td> 36 </tr> 37 </c:forEach> 38 </tbody> 39 </table> 40 <p>当前 $pageInfo.pageNum 页,总$pageInfo.pages 41 页,总 $pageInfo.total 条记录 42 </p> 43 <a href="list?pageNo=$pageInfo.getFirstPage()">首页</a> 44 <c:if test="$pageInfo.hasPreviousPage "> 45 <a href="list?pageNo=$pageInfo.pageNum-1">上一页</a> 46 </c:if> 47 48 <c:if test="$pageInfo.hasNextPage "> 49 <a href="list?pageNo=$pageInfo.pageNum+1">下一页</a> 50 </c:if> 51 52 <a href="list?pageNo=$pageInfo.getLastPage()">末页</a> 53 </div>
最终的效果如图所示：
水平有限，表述还是很不好
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