關於在SSM框架下使用PageHelper

首先，如果各位在這塊配置和代碼有什么問題歡迎說出來，我也會盡自己最大的能力幫大家解答

 這些代碼我都是寫在一個小項目里的，項目的github地址為：https://github.com/Albert-Best-Dong/parking，還希望哪個大佬給我這個小課題指點指點

jdk1.8,spring 4.3.18,mybatis 3.4.6,其實直接直接看pom文件就好了。

很長一段時間里，我學習編程很少總結代碼。后來代碼總結也只是寫在一個電腦里的文件夾，覺得與互聯網脫軌了，哈哈哈，所以現在也准備寫一寫博客，記錄自己，提高水平。

這是我的第一篇，也是關於SSM框架下使用PageHelper。

這里不具體寫我做的項目課題的全部內容，主要專注於PageHelper部分

工程結構如下圖：

首先在pom.xml（parking_dao模塊下）引入PageHelper依賴

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <parent>
        <artifactId>parking</artifactId>
        <groupId>com.dong</groupId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <modelVersion>4.0.0</modelVersion>

    <artifactId>parking_dao</artifactId>
    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.6</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis-spring</artifactId>
            <version>1.3.1</version>
        </dependency>
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-jdbc</artifactId>
            <version>${spring.version}</version>
        </dependency>
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>5.1.2</version>
        </dependency>
    </dependencies>

</project>

 

最主要的是：

<dependency>
    <groupId>com.github.pagehelper</groupId>
    <artifactId>pagehelper</artifactId>
    <version>5.1.2</version>
</dependency>
隨后需要在spring配置（spring-dao）文件里配置PageHelper

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
    http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/context
    http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.dong.parking.dao"/>

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
        <property name="url"
                  value="jdbc:mysql://localhost:3306/car_park?useUnicode=true&amp;characterEncoding=utf-8&amp;useSSL=false"/>
        <property name="username" value="root"/>
        <property name="password" value="root"/>
    </bean>

    <bean id="sessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="typeAliasesPackage" value="com.dong.parking.entity"/>
        <property name="dataSource" ref="dataSource"/>
        <!--配置PageHelper-->
        <property name="plugins">
            <array>
                <bean class="com.github.pagehelper.PageInterceptor">
                    <property name="properties">
                        <value>
                            offsetAsPageNum=true
                            rowBoundsWithCount=true
                            pageSizeZero=true
                            reasonable=true
                        </value>
                    </property>
                </bean>
            </array>
        </property>
    </bean>
    <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <property name="sqlSessionFactoryBeanName" value="sessionFactory"/>
        <property name="basePackage" value="com.dong.parking.dao"/>
    </bean>
</beans>

最主要的為：

<bean id="sessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
        <property name="typeAliasesPackage" value="com.dong.parking.entity"/>
        <property name="dataSource" ref="dataSource"/>
        <!--配置PageHelper-->
        <property name="plugins">
            <array>
                <bean class="com.github.pagehelper.PageInterceptor">
                    <property name="properties">
                        <value>
                            offsetAsPageNum=true
                            rowBoundsWithCount=true
                            pageSizeZero=true
                            reasonable=true
                        </value>
                    </property>
                </bean>
            </array>
        </property>
    </bean>

Ok，關於配置已經好了，現在進入parking，結構如下，以紅框標識的為例

ParkSpaceController代碼如下

package com.dong.parking.controller;

import com.dong.parking.biz.ParkSpaceBiz;
import com.dong.parking.entity.ParkSpace;
import com.dong.parking.entity.User;
import com.dong.parking.global.Constant;
import com.github.pagehelper.Page;
import com.github.pagehelper.PageHelper;
import com.github.pagehelper.PageInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import javax.servlet.http.HttpSession;
import java.util.List;
import java.util.Map;

@Controller("parkSpaceController")
@RequestMapping("/parkSpace")
public class ParkSpaceController {
    @Autowired
    private ParkSpaceBiz parkSpaceBiz;

    @RequestMapping(value = "/list")
    public String list(Map<String, Object> map, @RequestParam(value = "status", required = false) Integer status,
                       @RequestParam(defaultValue = "1", required = true, value = "pageNo") Integer pageNo) {
        List<ParkSpace> list = null;
        Integer pageSize = 2;
        PageHelper.startPage(pageNo, pageSize);
        if (status == null)
            list = parkSpaceBiz.findAll();
        else
            list = parkSpaceBiz.findByStatus(status);


        PageInfo<ParkSpace> pageInfo = new PageInfo<ParkSpace>(list);
        map.put("pageInfo", pageInfo);
        return "park_space_list";
    }

    @RequestMapping("/to_update")
    public String toUpdate(Map<String, Object> map, @RequestParam int id) {
        map.put("floor", Constant.getFloor());
        map.put("area", Constant.getArea());
        map.put("parkSpace", parkSpaceBiz.findById(id));
        return "park_space_update";
    }

    @RequestMapping("/update")
    public String update(ParkSpace parkSpace, HttpSession session) {
        User user = (User) session.getAttribute("user");
        parkSpace.setUpdateBy(user.getSn());
        parkSpaceBiz.edit(parkSpace);
        return "redirect:list";
    }


    @RequestMapping("/to_add")
    public String toAdd(Map<String, Object> map) {
        map.put("floor", Constant.getFloor());
        map.put("area", Constant.getArea());
        map.put("parkSpace", new ParkSpace());
        return "park_space_add";
    }

    @RequestMapping("/add")
    public String add(ParkSpace parkSpace, HttpSession session) {
        User user = (User) session.getAttribute("user");
        parkSpace.setCreateBy(user.getSn());
        parkSpace.setUpdateBy(user.getSn());
        parkSpaceBiz.add(parkSpace);
        return "redirect:list";
    }


    @RequestMapping(value = "/remove", params = "id")
    public String remove(int id) {
        parkSpaceBiz.remove(id);
        return "redirect:list";
    }
}

我們關注一下list方法

   @RequestMapping(value = "/list")
    public String list(Map<String, Object> map, @RequestParam(value = "status", required = false) Integer status,
                       @RequestParam(defaultValue = "1", required = true, value = "pageNo") Integer pageNo) {
        List<ParkSpace> list = null;
        Integer pageSize = 2;
        PageHelper.startPage(pageNo, pageSize);
        if (status == null)
            list = parkSpaceBiz.findAll();
        else
            list = parkSpaceBiz.findByStatus(status);


        PageInfo<ParkSpace> pageInfo = new PageInfo<ParkSpace>(list);
        map.put("pageInfo", pageInfo);
        return "park_space_list";
    }

這里的形參pageNo為前台傳來的值。這里的步驟可歸結如下

步驟1：PageHelper.startPage(pageNo,pageSize)，設置每頁顯示的個數和頁數

步驟2：List<Bean> list = beanService.find(),獲得bean的結合(這里以Bean代表一般的實體類)

步驟3：PageInfo<Bean> pageInfo = new PageInfo<Bean>(list);   將list集合封裝到pageInfo對象。

步驟4：map.put("pageInfo",pageInfo);將pageInfo對象回給前台

 

好了，現在咱們來到前台頁面，park_space_list.jsp代碼如下

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<jsp:include page="top.jsp"/>

<section id="content" class="table-layout animated fadeIn">
    <div class="tray tray-center">
        <div class="content-header">
            <h2> 員工列表 </h2>
            <p class="lead"></p>
        </div>
        <div class="admin-form theme-primary mw1000 center-block" style="padding-bottom: 175px;">
            <div class="panel  heading-border">
                <div class="panel-menu">
                    <div class="row">
                        <div class="hidden-xs hidden-sm col-md-3">
                            <div class="btn-group">
                                <button type="button" class="btn btn-default light">
                                    <i class="fa fa-refresh"></i>
                                </button>
                                <button type="button" class="btn btn-default light">
                                    <i class="fa fa-trash"></i>
                                </button>
                                <button type="button" class="btn btn-default light">
                                    <i class="fa fa-plus"
                                       onclick="javascript:window.location.href='/parkSpace/to_add';"></i>
                                </button>
                            </div>
                        </div>
                        <div class="col-xs-12 col-md-9 text-right">
                            <div class="btn-group">
                                <button type="button" class="btn btn-default light">
                                    <i class="fa fa-chevron-left"></i>
                                </button>

                                <button type="button" class="btn btn-default light">
                                    <i class="fa fa-chevron-right"></i>
                                </button>
                            </div>
                        </div>
                    </div>
                </div>
                <div class="panel-body pn">
                    <table id="message-table" class="table admin-form theme-warning tc-checkbox-1">
                        <thead>
                        <tr class="">
                            <th class="text-center hidden-xs">Select</th>
                            <th class="hidden-xs">樓層</th>
                            <th class="hidden-xs">區域</th>
                            <th class="hidden-xs">車位號</th>
                            <th class="hidden-xs">狀態</th>

                            <th>操作</th>
                        </tr>
                        </thead>
                        <tbody>
                        <c:forEach items="${pageInfo.list}" var="space">
                            <tr class="message-unread">
                                <td class="hidden-xs">
                                    <label class="option block mn">
                                        <input type="checkbox" name="mobileos" value="FR">
                                        <span class="checkbox mn"></span>
                                    </label>
                                </td>
                                <td>${space.floor}</td>
                                <td>${space.area}</td>
                                <td>${space.spaceId}</td>
                                <td>
                                    <c:if test="${space.status == 0}">空閑</c:if>
                                    <c:if test="${space.status == 1}">占用</c:if>
                                    <c:if test="${space.status == 2}">預定</c:if>
                                </td>

                                <td>
                                    <a href="/parkSpace/to_update?id=${space.id}">編輯</a>
                                    <a href="/parkSpace/remove?id=${space.id}">刪除</a>
                                </td>
                            </tr>
                        </c:forEach>
                        </tbody>
                    </table>
                    <p>當前 ${pageInfo.pageNum }頁,總${pageInfo.pages }
                        頁,總 ${pageInfo.total } 條記錄
                    </p>
                    <a href="list?pageNo=${pageInfo.getFirstPage()}">首頁</a>
                    <c:if test="${pageInfo.hasPreviousPage }">
                        <a href="list?pageNo=${pageInfo.pageNum-1}">上一頁</a>
                    </c:if>

                    <c:if test="${pageInfo.hasNextPage }">
                        <a href="list?pageNo=${pageInfo.pageNum+1}">下一頁</a>
                    </c:if>

                    <a href="list?pageNo=${pageInfo.getLastPage()}">末頁</a>
                </div>
            </div>
        </div>
    </div>
</section>

<jsp:include page="bottom.jsp"/>

我們關注於

      <div class="panel-body pn">
                    <table id="message-table" class="table admin-form theme-warning tc-checkbox-1">
                        <thead>
                        <tr class="">
                            <th class="text-center hidden-xs">Select</th>
                            <th class="hidden-xs">樓層</th>
                            <th class="hidden-xs">區域</th>
                            <th class="hidden-xs">車位號</th>
                            <th class="hidden-xs">狀態</th>

                            <th>操作</th>
                        </tr>
                        </thead>
                        <tbody>
                        <c:forEach items="${pageInfo.list}" var="space">
                            <tr class="message-unread">
                                <td class="hidden-xs">
                                    <label class="option block mn">
                                        <input type="checkbox" name="mobileos" value="FR">
                                        <span class="checkbox mn"></span>
                                    </label>
                                </td>
                                <td>${space.floor}</td>
                                <td>${space.area}</td>
                                <td>${space.spaceId}</td>
                                <td>
                                    <c:if test="${space.status == 0}">空閑</c:if>
                                    <c:if test="${space.status == 1}">占用</c:if>
                                    <c:if test="${space.status == 2}">預定</c:if>
                                </td>

                                <td>
                                    <a href="/parkSpace/to_update?id=${space.id}">編輯</a>
                                    <a href="/parkSpace/remove?id=${space.id}">刪除</a>
                                </td>
                            </tr>
                        </c:forEach>
                        </tbody>
                    </table>
                    <p>當前 ${pageInfo.pageNum }頁,總${pageInfo.pages }
                        頁,總 ${pageInfo.total } 條記錄
                    </p>
                    <a href="list?pageNo=${pageInfo.getFirstPage()}">首頁</a>
                    <c:if test="${pageInfo.hasPreviousPage }">
                        <a href="list?pageNo=${pageInfo.pageNum-1}">上一頁</a>
                    </c:if>

                    <c:if test="${pageInfo.hasNextPage }">
                        <a href="list?pageNo=${pageInfo.pageNum+1}">下一頁</a>
                    </c:if>

                    <a href="list?pageNo=${pageInfo.getLastPage()}">末頁</a>
                </div>

最終的效果如圖所示：

水平有限，表述還是很不好