Pagehelper的 使用
作者：互联网
跟着我最后实现出来的效果图:
前端页面jsp：
1 <%--
2 Created by IntelliJ IDEA.
3 User: Administrator
4 Date: 2020/12/10
5 Time: 20:34
6 To change this template use File | Settings | File Templates.
7 --%>
8 <%@ page contentType="text/html;charset=UTF-8" language="java" %>
9 <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
10 <%@taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
11 <html>
12 <head>
13 <link href="${pageContext.request.contextPath}/static/css/bootstrap.css" rel="stylesheet">
14
15 <title>主页</title>
16 </head>
17 <body>
18 <div id="showDiv" align="center">
19 <h1>${userSession.userName},欢迎登陆!</h1>
20
21
22 <form action="/jsp/user/queryAll" method="get">
23 用户名查询<input type="text" id="userName" name="userName" value="${userName}"/>
24 用户角色:<select id="userRole" name="userRole">
25 <option value="0" selected="selected">--请选择--</option>
26 <c:forEach items="${roleList}" var="role">
27 <option ${role.id==userRole?"selected=selected":""} value="${role.id}">${role.roleName}</option>
28 </c:forEach>
29 </select>
30 <input id="but" type="button" value="查询">
31 </form>
32
33
34 <div id="showTable">
35 <a href="/jsp/user/insertdo">添加用户</a>
36 <table border="1px">
37 <tr>
38 <td>用户编码</td>
39 <td>用户名称</td>
40 <td>性别</td>
41 <td>生日</td>
42 <td>电话</td>
43 <td>用户角色</td>
44 <td>操作</td>
45 </tr>
46 <c:forEach items="${pageInfo.list}" var="user">
47 <tr>
48 <td>${user.userCode}</td>
49 <td>${user.userName}</td>
50 <td>
51 <c:if test="${user.gender==1}">
52 男
53 </c:if>
54 <c:if test="${user.gender==2}">
55 女
56 </c:if>
57 </td>
58
59 <td><fmt:formatDate value="${user.birthday}" pattern="yyyy-MM-dd"/></td>
60
61 <td>${user.phone}</td>
62 <td>
63 <c:if test="${user.userRole==1}">
64 系统管理员
65 </c:if>
66 <c:if test="${user.userRole==2}">
67 经理
68 </c:if>
69 <c:if test="${user.userRole==3}">
70 普通员工
71 </c:if>
72
73 </td>
74 <td>
75 <a class="userView" href="${pageContext.request.contextPath}/jsp/user/view/${user.id}">查看</a>
76 <a href="${pageContext.request.contextPath}/jsp/user/updateById?id=${user.id}">修改</a>
77 <a class="userDel" userId="${user.id}" href="javascript:void (0)">删除</a>
78 </td>
79 </tr>
80 </c:forEach>
81 </table>
82 <div>
83 <nav aria-label="Page navigation example">
84 <ul class="pagination justify-content-center">
85 <%--上一页的判断 如果是第一页则上一页和首页按钮消失--%>
86 <c:if test="${pageInfo.pageNum>1}">
87 <li class="page-item">
88 <a class="page-link"
89 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=1&userName=${userName}&userRole=${userRole}">首页</a>
90 </li>
91 <li class="page-item">
92 <a class="page-link"
93 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${pageInfo.prePage}&userName=${userName}&userRole=${userRole}"
94 tabindex="-1" aria-disabled="true">上一页</a>
95 </li>
96 </c:if>
97
98 <c:choose>
99 <%--判断总页数是否大于10页，
100 如果大于10页我们的最后一位数值算法是用 pageInfo.pages-9
101 如果小于10页我们的选择框只需要迭代到总页数 pageInfo.pages
102 --%>
103 <c:when test="${pageInfo.pages<=10}">
104 <c:choose>
105 <%--如果当前页小于6数字不需要往后加+1--%>
106 <c:when test="${pageInfo.pageNum<=6}">
107 <%--如果小于10页我们的选择框只需要迭代到总页数 pageInfo.pages--%>
108 <c:forEach var="num" begin="1" end="${pageInfo.pages}">
109 <c:choose>
110 <%--如果当前页被选中 加上样式 active--%>
111 <c:when test="${pageInfo.pageNum==num}">
112 <li class="page-item active">
113 <a class="page-link"
114 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${num}&userName=${userName}&userRole=${userRole}">${num}</a>
115 </li>
116 </c:when>
117 <c:otherwise>
118 <li class="page-item">
119 <a class="page-link"
120 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${num}&userName=${userName}&userRole=${userRole}">${num}</a>
121 </li>
122 </c:otherwise>
123 </c:choose>
124 </c:forEach>
125 </c:when>
126 <c:otherwise>
127 <c:choose>
128 <%--这里也是计算下次最后页的数值，11<=7+4 --%>
129 <c:when test="${pageInfo.pages<=(pageInfo.pageNum+4)}">
130 <%--总页数大于10的情况--%>
131 <c:forEach var="num" begin="1" end="${pageInfo.pages}">
132 <c:choose>
133 <c:when test="${pageInfo.pageNum==num}">
134 <li class="page-item active">
135 <a class="page-link"
136 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${num}&userName=${userName}&userRole=${userRole}">${num}</a>
137 </li>
138 </c:when>
139 <c:otherwise>
140 <li class="page-item">
141 <a class="page-link"
142 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${num}&userName=${userName}&userRole=${userRole}">${num}</a>
143 </li>
144 </c:otherwise>
145 </c:choose>
146 </c:forEach>
147 </c:when>
148 <c:otherwise>
149
150 <%--保证每次都是10个选择框--%>
151 <c:forEach var="num" begin="${pageInfo.pageNum-5}" end="${pageInfo.pageNum+4}">
152 <c:choose>
153 <c:when test="${pageInfo.pageNum==mun}">
154 <li class="page-item active">
155 <a class="page-link"
156 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${mun}&userName=${userName}&userRole=${userRole}"
157 tabindex="-1" aria-disabled="true">${mun}</a>
158 </li>
159 </c:when>
160 <c:otherwise>
161 <li class="page-item">
162 <a class="page-link"
163 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${num}&userName=${userName}&userRole=${userRole}"
164 tabindex="-1" aria-disabled="true">${num}</a>
165 </li>
166 </c:otherwise>
167 </c:choose>
168 </c:forEach>
169 </c:otherwise>
170 </c:choose>
171 </c:otherwise>
172 </c:choose>
173 </c:when>
174
175 <c:otherwise>
176 <c:choose>
177 <c:when test="${pageInfo.pageNum<=6}">
178 <c:forEach var="num" begin="1" end="10">
179 <c:choose>
180 <c:when test="${pageInfo.pageNum==num}">
181 <li class="page-item active">
182 <a class="page-link"
183 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${num}&userName=${userName}&userRole=${userRole}">${num}</a>
184 </li>
185 </c:when>
186 <c:otherwise>
187 <li class="page-item">
188 <a class="page-link"
189 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${num}&userName=${userName}&userRole=${userRole}">${num}</a>
190 </li>
191 </c:otherwise>
192 </c:choose>
193 </c:forEach>
194 </c:when>
195 <c:otherwise>
196 <c:choose>
197 <c:when test="${pageInfo.pages<=(pageInfo.pageNum+4)}">
198 <%--总页数大于10的情况,如果大于10页我们的最后一位数值算法是用 pageInfo.pages-9--%>
199 <c:forEach var="num" begin="${pageInfo.pages-9}" end="${pageInfo.pages}">
200 <c:choose>
201 <c:when test="${pageInfo.pageNum==num}">
202 <li class="page-item active">
203 <a class="page-link"
204 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${num}&userName=${userName}&userRole=${userRole}">${num}</a>
205 </li>
206 </c:when>
207 <c:otherwise>
208 <li class="page-item">
209 <a class="page-link"
210 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${num}&userName=${userName}&userRole=${userRole}">${num}</a>
211 </li>
212 </c:otherwise>
213 </c:choose>
214 </c:forEach>
215 </c:when>
216 <c:otherwise>
217 <c:forEach var="num" begin="${pageInfo.pageNum-5}"
218 end="${pageInfo.pageNum+4}">
219 <c:choose>
220 <c:when test="${pageInfo.pageNum==mun}">
221 <li class="page-item active">
222 <a class="page-link"
223 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${mun}&userName=${userName}&userRole=${userRole}"
224 tabindex="-1" aria-disabled="true">${mun}</a>
225 </li>
226 </c:when>
227 <c:otherwise>
228 <li class="page-item">
229 <a class="page-link"
230 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${num}&userName=${userName}&userRole=${userRole}"
231 tabindex="-1" aria-disabled="true">${num}</a>
232 </li>
233 </c:otherwise>
234 </c:choose>
235 </c:forEach>
236 </c:otherwise>
237 </c:choose>
238 </c:otherwise>
239 </c:choose>
240 </c:otherwise>
241 </c:choose>
242
243
244 <%--下一页 按钮限制 如果当前页是最后一页 则下一页和尾页按钮消失--%>
245 <c:if test="${pageInfo.pageNum<pageInfo.pages}">
246 <li class="page-item">
247 <a class="page-link"
248 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${pageInfo.nextPage}&userName=${userName}&userRole=${userRole}">下一页</a>
249 </li>
250 <li class="page-item">
251 <a class="page-link"
252 href="${pageContext.request.contextPath}/jsp/user/queryAll?pageNum=${pageInfo.pages}&userName=${userName}&userRole=${userRole}">尾页</a>
253 </li>
254 </c:if>
255 </ul>
256 </nav>
257 </div>
258 </div>
259 </div>
260 <script type="text/javascript" src="${pageContext.request.contextPath }/static/js/jquery-1.8.3.min.js"></script>
261 <script type="text/javascript" src="${pageContext.request.contextPath }/static/js/page.js"></script>
262 <script type="text/javascript" src="${pageContext.request.contextPath }/static/js/userview.js"></script>
263 <script src="${pageContext.request.contextPath}/static/js/jquery-3.5.1.js"></script>
264 <script src="${pageContext.request.contextPath}/static/js/jquery-migrate-1.0.0.js"></script>
265 <script src="${pageContext.request.contextPath}/static/js/bootstrap.js"></script>
266 </body>
267 </html>
service层代码:
1 public List<User> selectByExample(Integer pageNum,Integer pageSize,String userName,Long userRole) {
2 UserExample userExample=new UserExample();
3 UserExample.Criteria criteria = userExample.createCriteria();
4 if(userName==null){
5 userName="";
6 }
7 if(userName!=null&&!"".equals(userName)){
8 System.out.println("我进来了userName");
9 criteria.andUserNameLike("%"+userName+"%");
10 }
11 if(userRole!=null&&userRole!=0){
12 System.out.println("我进来了userRole");
13 criteria.andUserRoleEqualTo(userRole);
14 }
15 PageHelper.startPage(pageNum,pageSize);
16 List<User> users = userMapper.selectByExample(userExample);
17 System.out.println(pageNum+"--"+pageSize+"--"+userName+"--"+userRole);
18 return users;
19 }
contorller 代码:
@RequestMapping("/queryAll")
public String queryAll(Model model,Integer pageNum, Integer pageSize,String userName,Long userRole){
if(pageNum==null||pageNum.equals("")){
pageNum= Constant.PAGE_NUM;
}
if(pageSize==null){
pageSize=Constant.PAGE_SIZE;
}
/* if(userRole==null){
userRole=0L;
}*/
List<Role> roleList = userService.getRoleList();
List<User> users = userService.selectByExample(pageNum, pageSize,userName,userRole);
PageInfo<User> pageInfo=new PageInfo<>(users);
System.out.println("userRole-----="+userRole);
model.addAttribute("pageInfo",pageInfo);
model.addAttribute("userName",userName);
model.addAttribute("userRole",userRole);
model.addAttribute("roleList",roleList);
return "main";
}
这里使用了pageInfo的一个pageHelper的工具包
PageInfo<User> pageInfo=new PageInfo<User>(users);
里面有许多封装好的方法，可以直接调用 列如
1.pageInfo.pages 总页数
2.pageInfo.pageNum 当前页
3.pageInfo.nextPage 下一页
4.pageInfo.prePage 上一页
运行效果:
1.第一页的时候页面没有上一页和首页
在第二页的时候我们的上一页就显示出来了
3.多条件查询也是跟着分页来的
标签：userName,pageNum,pageSize,Pagehelper,num,userRole,使用,pageInfo 来源： https://www.cnblogs.com/KcBlog/p/14146182.html