SpringMvc+Maven框架下简单分页实现
SpringMvc+Maven框架下简单分页实现
分页是开发中最基本但必不可少的部分，之前在学校也没有那么多数据，一直以来对分页也没怎么重视，都是用别人现成的，最近自己尝试着写了个分页模块，顺便记录下方便之后使用。具体实现主要从以下几个部分实现：
1.分页实体类
首先我们需要一个工具类，如下内容所示：
package com.cn.hnust.pojo;
import java.io.Serializable;
/**
* 分页
*/
public class Page implements Serializable {
private static final long serialVersionUID = -3198048449643774660L;
private int pageNow = 1; // 当前页数
private int pageSize = 4; // 每页显示记录的条数
private int totalCount; // 总的记录条数
private int totalPageCount; // 总的页数
@SuppressWarnings("unused")
private int startPos; // 开始位置，从0开始
@SuppressWarnings("unused")
private boolean hasFirst;// 是否有首页
@SuppressWarnings("unused")
private boolean hasPre;// 是否有前一页
@SuppressWarnings("unused")
private boolean hasNext;// 是否有下一页
@SuppressWarnings("unused")
private boolean hasLast;// 是否有最后一页
/**
* 通过构造函数 传入 总记录数 和 当前页
* @param totalCount
* @param pageNow
*/
public Page(int totalCount, int pageNow) {
this.totalCount = totalCount;
this.pageNow = pageNow;
}
/**
* 取得总页数，总页数=总记录数/总页数
* @return
*/
public int getTotalPageCount() {
totalPageCount = getTotalCount() / getPageSize();
return (totalCount % pageSize == 0) ? 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
* @return
*/
public int getStartPos() {
return (pageNow - 1) * pageSize;
}
public void setStartPos(int startPos) {
this.startPos = startPos;
}
/**
* 是否是第一页
* @return
*/
public boolean isHasFirst() {
return (pageNow == 1) ? false : true;
}
public void setHasFirst(boolean hasFirst) {
this.hasFirst = hasFirst;
}
/**
* 是否有首页
* @return
*/
public boolean isHasPre() {
// 如果有首页就有前一页，因为有首页就不是第一页
return isHasFirst() ? true : false;
}
public void setHasPre(boolean hasPre) {
this.hasPre = hasPre;
}
/**
* 是否有下一页
* @return
*/
public boolean isHasNext() {
// 如果有尾页就有下一页，因为有尾页表明不是最后一页
return isHasLast() ? true : false;
}
public void setHasNext(boolean hasNext) {
this.hasNext = hasNext;
}
/**
* 是否有尾页
* @return
*/
public boolean isHasLast() {
// 如果不是最后一页就有尾页
return (pageNow == getTotalCount()) ? false : true;
}
public void setHasLast(boolean hasLast) {
this.hasLast = hasLast;
}
}2.Mybatis xml 文件配置
在有了上述分页实体之后，接下来就需要在Mybatis XXmapper.xml文件中配置查询语句，具体思路是：
a. 查询出所有符合条件的结果总数
b.将查到的结果总数通过分页实体的构造函数传入，然后计算出分页参数
c.根据分页参数查询结果集返回
- 查询所有符合条件的记录条数
<select id="getCounts" resultType="int" parameterType="java.util.Map">
SELECT COUNT(*) FROM book
WHERE XX=查询条件
select>- 根据分页参数查询符合条件的list
<select id="getBookByPage" resultMap="BaseResultMap">
select
"Base_Column_List" />
,
"Blob_Column_List" />
from book WHERE (1=1
"bookParams" /> 这里自己的查询条件)
order by Id DESC
limit #{startPos--起始下标},#{pageSize--每页数量}
select> 3.Controller –Service–Dao 层调用代码
- Controller 层代码
@RequestMapping("/getBookByPage")
public String getBookByPage(HttpServletRequest request, Model model,Book book, HttpSession session, Type type, Subtype sub) {
List bookList = new ArrayList();
int counts;// 分页记录总数
String pageNow = request.getParameter("pageNow");
String countString = request.getParameter("allcount");
Page page = null;
// 判断分页参数
Book bookParams = (Book) session.getAttribute("bookParams");
if (countString != null) {
counts = Integer.parseInt(countString);
book = bookParams;
} else {
counts = bookService.getCounts(book);
}
// 添加查询条件id name author publish type subtype
// System.out.println(book.getName() + "|" + book.getAuthor() + "|"
// + book.getPublish() + "|" + book.getType() + "|"
// + book.getSubtype());
Map condition = new HashMap();
condition.put("id", book.getId());
condition.put("name", book.getName());
condition.put("publish", book.getPublish());
condition.put("type", book.getType());
condition.put("subtype", book.getSubtype());
if (pageNow != null && pageNow != "") {
page = new Page(counts, Integer.parseInt(pageNow));
} else {
page = new Page(counts, 1);
}
condition.put("startPos", page.getStartPos());
condition.put("pageSize", page.getPageSize());
bookList = this.bookService.getBookByPage(condition);
// System.out.println("list.size():" + bookList.size());
model.addAttribute("bookList", bookList);
model.addAttribute("page", page);
model.addAttribute("bookParams", book);
session.setAttribute("bookParams", book);
model.addAttribute("url", "/book/getBookByPage");
// 下面判断是否从删除页面跳转过来
String deleted = (String) session.getAttribute("bookDeleted");
// System.out.println(deleted);
if (deleted != null) {
model.addAttribute("bookDeleted", deleted);
session.removeAttribute("bookDeleted");
}
model.addAttribute("subList", subList);
return "book/list";
} - Service 层代码
@Resource
private BookDao bookDao;
public int getCounts(Book book) {
// TODO Auto-generated method stub
return bookDao.getCounts(book);
}
public List getBookByPage(Map condition) {
// TODO Auto-generated method stub
return bookDao.getBookByPage(condition);
} - Dao 层代码
int getCounts(Book book);
List getBookByPage(Map condition); 4.前端jsp页面代码
前端页面page,公用jsp
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<form action='至此，分页功能已经完成，效果图如下：
