前言
最近因为工作的原因,在使用SSM框架实现一个商品信息展示的功能,商品的数据较多,不免用到分页,查了一番MyBatis分页的做法,终于是实现了,在这里记录下来分享给大家,下面来一起看看详细的介绍:
方法如下:
首先写一个分页的工具类,定义当前页数,总页数,每页显示多少等属性。
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
|
/** * 分页 工具类 */ public class Page implements Serializable { private static final long serialVersionUID = -2213069645383858323L; 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 private int startPos; // 开始位置,从0开始 private boolean hasFirst; // 是否有首页 private boolean hasPre; // 是否有前一页 private boolean hasNext; // 是否有下一页 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; } } |
接着Mapper接口中定义分类的方法
传入两个参数,分别是开始页和每页显示记录的条数。
Mapper的映射文件中的SQL分页语句
1
2
3
4
|
< select id = "findPages" resultType = "com.dh15.pojo.Goods" > select g.id,g.name,g.price,g.num,c.class_name,g.pic,g.des from tb_goods g,tb_class c where g.class_id=c.cid limit #{startPos},#{pageSize} </ select > |
接着在控制类(Controller)中查询商品,同时进行分页。
查询商品方法
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
|
/** * 查询商品信息,实现分页 * @param goods * @return * @throws Exception */ @RequestMapping ( "/queryPages" ) public String queryPages(HttpServletRequest request, Model model) throws Exception { String pageNow = request.getParameter( "pageNow" ); Page page = null ; List<Goods> goods = new ArrayList<Goods>(); int totalCount = ( int ) service.getGoodsCount( 1 ); if (pageNow != null ) { page = new Page(totalCount, Integer.parseInt(pageNow)); goods = this .service.findPages(page.getStartPos(), page.getPageSize()); } else { page = new Page(totalCount, 1 ); goods = this .service.findPages(page.getStartPos(), page.getPageSize()); } model.addAttribute( "goods_list" , goods); model.addAttribute( "page" , page); return "goods/FenYeTest" ; } |
这里需要注意一下,遍历商品时没有点击页数,所以当前页默认是空的,这里要在方法里面进行判断,如果pageNow为空,传一个1到构造函数,否则会报空指针。
最后,在jsp页面显示查询的商品列表,同时实现点击上一页,下一页,首页,尾页等常见分页中的操作
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
|
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/fmt" prefix="fmt"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> < html > < head > < meta http-equiv = "Content-Type" content = "text/html; charset=UTF-8" > < title >商品查询列表</ title > </ head > < body > < table width = "100%" border = 1 > < tr > < td >选择</ td > < td >商品名称</ td > < td >商品价格</ td > < td >生产数量</ td > < td >商品类别</ td > < td >商品图片</ td > < td >商品信息</ td > < td >操作</ td > </ tr > < c:forEach items = "${goods_list }" var = "item" > < tr > < td >${item.id}< input type = "hidden" name = "id" value = "${item.id}" /></ td > < td >${item.name }</ td > < td >${item.price }</ td > < td >${item.num }</ td > < td >${item.classInfo.class_name }</ td > < td >< img style = "width:110px;height:120px" alt = "商品图片" src = "http://localhost/pic/${item.pic }" ></ td > < td >${item.des }</ td > < td > < a href = "${pageContext.request.contextPath }/findGoodsById.action?id=${item.id}" rel = "external nofollow" >修改</ a > < a href = "${pageContext.request.contextPath }/delGoods.action?id=${item.id}" rel = "external nofollow" >删除</ a > </ td > </ tr > </ c:forEach > </ table > < div align = "center" > < font size = "2" >第 ${page.pageNow} 页</ font > < a href = "queryPages.action?pageNow=1" rel = "external nofollow" rel = "external nofollow" >首页</ a > < c:choose > < c:when test="${page.pageNow - 1 > 0}"> < a href = "queryPages.action?pageNow=${page.pageNow - 1}" rel = "external nofollow" >上一页</ a > </ c:when > < c:when test = "${page.pageNow - 1 <= 0}" > < a href = "queryPages.action?pageNow=1" rel = "external nofollow" rel = "external nofollow" >上一页</ a > </ c:when > </ c:choose > < c:choose > < c:when test = "${page.totalPageCount==0}" > < a href = "queryPages.action?pageNow=${page.pageNow}" rel = "external nofollow" rel = "external nofollow" >下一页</ a > </ c:when > < c:when test = "${page.pageNow + 1 < page.totalPageCount}" > < a href = "queryPages.action?pageNow=${page.pageNow + 1}" rel = "external nofollow" >下一页</ a > </ c:when > < c:when test="${page.pageNow + 1 >= page.totalPageCount}"> < a href = "queryPages.action?pageNow=${page.totalPageCount}" rel = "external nofollow" rel = "external nofollow" >下一页</ a > </ c:when > </ c:choose > < c:choose > < c:when test = "${page.totalPageCount==0}" > < a href = "queryPages.action?pageNow=${page.pageNow}" rel = "external nofollow" rel = "external nofollow" >尾页</ a > </ c:when > < c:otherwise > < a href = "queryPages.action?pageNow=${page.totalPageCount}" rel = "external nofollow" rel = "external nofollow" >尾页</ a > </ c:otherwise > </ c:choose > </ div > </ body > </ html > |
最终效果图:
总结
以上就是这篇文章的全部内容了,希望本文的内容对大家的学习或者工作能带来一定的帮助,如果有疑问大家可以留言交流,谢谢大家对服务器之家的支持。
原文链接:http://blog.csdn.net/weixin_36380516/article/details/73606693