记一次 SSM 分页

1.实体层(entity,pojo,domain)

package com.entity;

import java.io.Serializable;

      private int totalCount;      //总记录数

      private int totalPageCount;  //总页数

      private int startPos;        //开始位置，从0开始

      private boolean hasFrist;    //是否有首页

      private boolean hasPre;      //是否有前一页

      private boolean hasNext;     //是否有后一页

      private boolean hasLast;     //是否有尾页

      /**
       * 通过构造函数，传入总记录数和当前页
       * @param pageNow
       * @param totalCount
       */
      public CountPage(int pageNow, int totalCount) {
          super();
          this.pageNow = pageNow;
          this.totalCount = totalCount;
      }
      //获取总页数
      public int getTotalPageCount() {
          totalPageCount=getTotalCount()/getPageSize();
          return (totalCount/pageSize==1) ? totalPageCount:totalPageCount+1;
      }

      public void setTotalPageCount(int totalPageCount) {
          this.totalPageCount = totalPageCount;
      }

      public int getPageNow() {
          return pageNow;
      }

      public void setPageNow(int pageNow) {
          this.pageNow = pageNow;
      }

      public int getPageSize() {
          return pageSize;
      }

      public void setPageSize(int pageSize) {
          this.pageSize = pageSize;
      }

      public int getTotalCount() {
          return totalCount;
      }

      public void setTotalCount(int totalCount) {
          this.totalCount = totalCount;
      }
      //取得选择记录的初始位置
      public int getStartPos() {
          return (pageNow-1)*pageSize;
      }

      public void setStartPos(int startPos) {
          this.startPos = startPos;
      }
      //判断是否有第一页
      public boolean isHasFrist() {
          return (pageNow==1) ? false:true;
      }

      public void setHasFrist(boolean hasFrist) {
          this.hasFrist = hasFrist;
      }
      //如果有首页就有前一页
      public boolean isHasPre() {
          return isHasFrist() ? true:false;
      }

      public void setHasPre(boolean hasPre) {
          this.hasPre = hasPre;
      }
      //如果有尾页就有下一页
      public boolean isHasNext() {
          return isHasNext() ? true:false;
      }

      public void setHasNext(boolean hasNext) {
          this.hasNext = hasNext;
      }
      //判断是否有尾页
      public boolean isHasLast() {
          return (pageNow==getTotalCount()) ? false:true;
      }

      public void setHasLast(boolean hasLast) {
          this.hasLast = hasLast;
      }

}

2.DAO层

package com.dao;

import java.util.List;

import com.entity.MyAccount;

public interface MyAccountMapper {

    /*  查询所有   传值（当前页，每页显示多少条数据） */
    List<MyAccount> findAll(Integer pageNow,Integer pageSize);
    /*  查询总数  */
    Integer myAccountCount();

}

3.xxxmapper.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.dao.MyAccountMapper" >
            <!-- 查询所有 并用 limit 进行 分页 -->
            <select id="findAll" resultType="com.entity.MyAccount">
                    select * from account limit #{0},#{1}
            </select>
            <!-- 查询总数 -->
            <select id="accountCount" resultType="Integer">
                    select COUNT(*) from account
            </select>
</mapper>

4.服务层(service)

package com.service;

import java.util.List;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import com.dao.MyAccountMapper;
import com.entity.MyAccount;

@Transactional
@Service
public class AccountService {

    @Autowired
    MyAccountMapper accountMapper = null;

    /**
     * 查询 所有 账户
     */
    public List<MyAccount> findAll(Integer pageNow,Integer pageSize){
         System.out.println("业务查询  >>> 查询我的所有账户");
         List<MyAccount> list = accountMapper.findAll(pageNow, pageSize);
         System.out.println("查询到的结果是 >>> " + list.toString());
        return list;
    }

    /**
     * 查询 总页数
     */
    public Integer myAccountCount(){
         System.out.println("业务查询  >>> 查询所有账户数量");
         return accountMapper.myAccountCount();
    }
}

5.控制层(Controller)

package com.web;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

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

import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;

import com.entity.CountPage;
import com.entity.MyAccount;
import com.service.AccountService;

@Controller
public class AccountController {

    @Resource
    AccountService accountService = null;

    /**
     *    查询所有账户
     */
    @RequestMapping(value = "/account")
    public String findAll(Model model,HttpServletRequest request){

        //获取当前页数
        String pageNow=request.getParameter("pageNow");
        //获取总页数
        int totalCount=(int)accountService.myAccountCount();
        //初始化 CountPage 对象 page
        CountPage page=null;
        //new 一个 集合  把数据 放进集合里
        List<MyAccount> list=new ArrayList<MyAccount>();
        if (pageNow!=null) {
            page=new CountPage(Integer.parseInt(pageNow), totalCount);
            list=this.accountService.findAll(page.getStartPos(),page.getPageSize());
        }else {
            page=new CountPage(1, totalCount);
            list=this.accountService.findAll(page.getStartPos(),page.getPageSize());
        }
        //把数据放到 model 中并转发到 jsp 页面
        model.addAttribute("list", list);
        model.addAttribute("page", page);
        return "myaccount";
    }
}

6.页面代码(JSP)

<div class="pager">
          <font size="2">共 ${page.totalPageCount} 页</font> <font size="2">第
            ${page.pageNow} 页</font> <a href="account?pageNow=1">首页</a>
        <c:choose>
            <c:when test="${page.pageNow - 1 > 0}">
                <a href="account?pageNow=${page.pageNow - 1}">上一页</a>
            </c:when>
            <c:when test="${page.pageNow - 1 <= 0}">
                <a href="account?pageNow=1">上一页</a>
            </c:when>
        </c:choose>
        <c:choose>
            <c:when test="${page.totalPageCount==0}">
                <a href="account?pageNow=${page.pageNow}">下一页</a>
            </c:when>
            <c:when test="${page.pageNow + 1 < page.totalPageCount}">
                <a href="account?pageNow=${page.pageNow + 1}">下一页</a>
            </c:when>
            <c:when test="${page.pageNow + 1 >= page.totalPageCount}">
                <a href="account?pageNow=${page.totalPageCount}">下一页</a>
            </c:when>
        </c:choose>
        <c:choose>
            <c:when test="${page.totalPageCount==0}">
                <a href="account?pageNow=${page.pageNow}">尾页</a>
            </c:when>
            <c:otherwise>
                <a href="account?pageNow=${page.totalPageCount}">尾页</a>
            </c:otherwise>
        </c:choose>
       </div>

注：其中 <a href="account?pageNow=1">首页</a>  ( account  是 控制层(Controller) @RequestMapping(value = "/account") 的值)