为什么我写的和老师的代码一样,页面却不显示数据呢,
来源:3-4 列表显示页面跳转的代码实现
qq_慕UI0173712
2019-08-16 13:40:22
这是category_list.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %> <!DOCTYPE html> <html> <!-- Mirrored from admindesigns.com/demos/absolute/1.1/admin_forms-validation.html by HTTrack Website Copier/3.x [XR&CO'2014], Thu, 06 Aug 2015 02:56:15 GMT --> <head> <!-- Meta, title, CSS, favicons, etc. --> <meta charset="utf-8"> <title> 商城--分类列表 </title> <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath }/assets/skin/default_skin/css/theme.css"> <link rel="stylesheet" type="text/css" href="${pageContext.request.contextPath }/assets/admin-tools/admin-forms/css/admin-forms.css"> <link rel="shortcut icon" href="${pageContext.request.contextPath }/assets/img/favicon.ico"> </head> <body class="admin-validation-page" data-spy="scroll" data-target="#nav-spy" data-offset="200"> <div id="main"> <%@ include file="header.jsp" %> <%@ include file="left.jsp" %> <section id="content_wrapper"> <section id="content" class="table-layout animated fadeIn"> <div class="tray tray-center"> <div class="content-header"> <h2> 分类列表 </h2> <p class="lead"></p> </div> <div class="admin-form theme-primary mw1000 center-block" style="padding-bottom: 175px;"> <div class="panel heading-border"> <div class="panel-menu"> <div class="row"> <div class="hidden-xs hidden-sm col-md-3"> <div class="btn-group"> <button type="button" class="btn btn-default light"> <i class="fa fa-refresh"></i> </button> <button type="button" class="btn btn-default light"> <i class="fa fa-trash"></i> </button> <button type="button" class="btn btn-default light"> <i class="fa fa-plus" onclick="javascript:window.location.href='/employee/to_add';"></i> </button> </div> </div> <div class="col-xs-12 col-md-9 text-right"> <div class="btn-group"> <button type="button" class="btn btn-default light"> <i class="fa fa-chevron-left"></i> </button> <button type="button" class="btn btn-default light"> <i class="fa fa-chevron-right"></i> </button> </div> </div> </div> </div> <div class="panel-body pn"> <table id="message-table" class="table admin-form theme-warning tc-checkbox-1"> <thead> <tr class=""> <th class="hidden-xs">名称</th> <th class="hidden-xs">描述</th> <th>操作</th> </tr> </thead> <tbody> <c:forEach var=" category " items="${list }"> <tr class="message-unread"> <td>${category.cname }</td> <td>${category.cdesc}</td> <td> <a href="#">编辑</a> <a href="#">删除</a> </td> </tr> </c:forEach> </tbody> </table> </div> </div> </div> </div> </section> </section> </div> <style> /* demo page styles */ body { min-height: 2300px; } .content-header b, .admin-form .panel.heading-border:before, .admin-form .panel .heading-border:before { transition: all 0.7s ease; } /* responsive demo styles */ @media (max-width: 800px) { .admin-form .panel-body { padding: 18px 12px; } } </style> <style> .ui-datepicker select.ui-datepicker-month, .ui-datepicker select.ui-datepicker-year { width: 48%; margin-top: 0; margin-bottom: 0; line-height: 25px; text-indent: 3px; color: #888; border-color: #DDD; background-color: #FDFDFD; -webkit-appearance: none; /*Optionally disable dropdown arrow*/ } </style> <script src=" ${pageContext.request.contextPath } /vendor/jquery/jquery-1.11.1.min.js"></script> <script src=" ${pageContext.request.contextPath } /vendor/jquery/jquery_ui/jquery-ui.min.js"></script> <script src=" ${pageContext.request.contextPath }/ assets/admin-tools/admin-forms/js/jquery.validate.min.js"></script> <script src=" ${pageContext.request.contextPath } /assets/admin-tools/admin-forms/js/additional-methods.min.js"></script> <script src=" ${pageContext.request.contextPath } /assets/admin-tools/admin-forms/js/jquery-ui-datepicker.min.js"></script> <script src=" ${pageContext.request.contextPath }/ assets/js/utility/utility.js"></script> <script src=" ${pageContext.request.contextPath } /assets/js/demo/demo.js"></script> <script src=" ${pageContext.request.contextPath }/ assets/js/main.js"></script> <script type="text/javascript" src=" ${pageContext.request.contextPath } /js/pages.js"></script> <script type="text/javascript" src=" ${pageContext.request.contextPath } /js/items.js"></script> </body> </html>
这是CategoryDaoImpl.java
package com.winking.dao.impl; import java.sql.Connection; import java.sql.PreparedStatement; import java.sql.ResultSet; import java.util.ArrayList; import java.util.List; import com.winking.dao.CategoryDao; import com.winking.domain.Category; import com.winking.utils.JDBCUtils; public class CategoryDaoImpl implements CategoryDao { @Override public List<Category> findAll() { System.out.println("CategoryDao的findAll方法执行了..."); Connection conn =null; PreparedStatement pstmt=null; ResultSet rs=null; List<Category> list = null; try { //1.获得连接 conn=JDBCUtils.getConnection(); //2.编写SQL String sql ="select * from category"; //3.预编译SQL pstmt= conn.prepareStatement(sql); //4.设置参数 //5.执行SQL rs=pstmt.executeQuery(); //6.结果处理 list= new ArrayList<Category>(); while(rs.next()) { Category category= new Category(); category.setCid(rs.getInt("cid")); category.setCname(rs.getString("cname")); category.setCdesc(rs.getString("cdes")); list.add(category); } }catch(Exception e) { e.printStackTrace(); }finally { //7.释放资源 JDBCUtils.release(rs, pstmt,conn); } return list; } }
3回答
同学你好!
同学这里var后面的空格也会被定义为这个变量的名字里面,这样变量的名字就是:
空格+category+空格。所以通过category就获取不到值了,同学将前后的空格去掉就可以了
如果我的回答解决了你的疑惑,请采纳,祝学习愉快~
qq_慕UI0173712
提问者
2019-08-16
好帮手慕柯南
2019-08-16
同学你好!
数据库中有数据吗?
是否将查询到的数据返回页面
idea或者浏览器的控制台是否报错。
如果我的回答解决了你的疑惑,请采纳,祝学习愉快~
相似问题