查询逻辑有问题
自己看的头晕，还是求助吧
问题描述：查询时输入不存在的数字还会查出来数据，SearchGoodsByIdServlet.java中的ifelse走不到else。条件有问题吗是。
还有jsp界面的textbox是不是要加check啊，或者这种练习意思到了就行，没必要加。
Goods.java
package com.imooc.goods;
public class Goods {
private Integer goodsId;
private String goodsName;
private String goodsType;
private Float price;
private String description;
public Goods() {
}
public Goods(Integer goodsId, String goodsName, String goodsType, Float price, String description) {
super();
this.goodsId = goodsId;
this.goodsName = goodsName;
this.goodsType = goodsType;
this.price = price;
this.description = description;
}
public Integer getgoodsId() {
return goodsId;
}
public void setgoodsId(Integer goodsId) {
this.goodsId = goodsId;
}
public String getGoodsName() {
return goodsName;
}
public void setGoodsName(String goodsName) {
this.goodsName = goodsName;
}
public String getGoodsType() {
return goodsType;
}
public void setGoodsType(String goodsType) {
this.goodsType = goodsType;
}
public Float getPrice() {
return price;
}
public void setPrice(Float price) {
this.price = price;
}
public String getDescription() {
return description;
}
public void setDescription(String description) {
this.description = description;
}
}GoodsAddServlet.java
package com.imooc.goods;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class CreateServlet
*/
@WebServlet("/create")
public class GoodsAddServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public GoodsAddServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
String goodsId = request.getParameter("goodsId");
String goodsName = request.getParameter("goodsName");
String goodsType = request.getParameter("goodsType");
String price = request.getParameter("price");
String description = request.getParameter("description");
Goods good = new Goods(Integer.parseInt(goodsId),goodsName,goodsType,Float.parseFloat(price),description);
ServletContext context = request.getServletContext();
List<Goods> goods = (List)context.getAttribute("goods");
goods.add(good);
context.setAttribute("goods", goods);
request.getRequestDispatcher("/goods.jsp").forward(request, response);
}
}GoodsListServlet.java
package com.imooc.goods;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class ListServlet
*/
@WebServlet("/list")
public class GoodsListServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public GoodsListServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
ServletContext context = request.getServletContext();
if (context.getAttribute("goods") == null) {
List<Goods> list = new ArrayList<Goods>();
Goods goods = new Goods(1001, "IPhone", "手机", 5499f, "可以打电话");
list.add(goods);
list.add(new Goods(1002, "Samsung", "手机", 6499f, "可以玩游戏"));
context.setAttribute("goods", list);
}
request.getRequestDispatcher("/goods.jsp").forward(request, response);
}
}SearchGoodsByIdServlet.java
package com.imooc.goods;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
* Servlet implementation class SearchServlet
*/
@WebServlet("/search")
public class SearchGoodsByIdServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public SearchGoodsByIdServlet() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String searchId = request.getParameter("id");
response.setContentType("text/html;charset=utf-8");
ServletContext context = request.getServletContext();
List<Goods> goods = (List)context.getAttribute("goods");
for(Goods good : goods) {
Integer goodsId = (Integer)good.getgoodsId();
if(Integer.parseInt(searchId) == goodsId) {
context.setAttribute("searchGoods", good);
}else{
response.getWriter().println("商品id不存在");
}
}
request.getRequestDispatcher("/searchById.jsp").forward(request, response);
}
}goods.jsp
<%@ page contentType="text/html; charset=utf-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c"%>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>商品列表</title>
<link href="css/bootstrap.css" type="text/css" rel="stylesheet">
</link>
<script type="text/javascript" src="js/jquery-1.11.1.min.js"></script>
<script type="text/javascript" src="js/bootstrap.js"></script>
<style type="text/css">
.pagination {
margin: 0px
}
.pagination>li>a, .pagination>li>span {
margin: 0 5px;
border: 1px solid #dddddd;
}
.glyphicon {
margin-right: 3px;
}
.form-control[readonly] {
cursor: pointer;
background-color: white;
}
#dlgPhoto .modal-body {
text-align: center;
}
.preview {
max-width: 500px;
}
</style>
<script>
$(function() {
$("#btnAdd").click(function() {
$('#dlgForm').modal()
});
})
</script>
</head>
<body>
<div class="container">
<div class="row">
<h1 style="text-align: center">IMOOC商品信息表</h1>
<div class="panel panel-default">
<div class="clearfix panel-heading ">
<div>
<label class="form-inline">
<div class="form-group" style="width: 850px;">
<button class="btn btn-primary" id="btnAdd">新增</button>
</div>
<div class="form-group pull-right">
<form action="/goods/search" method="post">
<input type="text" class="form-control" id="searchById"
name="id" placeholder="根据商品id进行查询">
<button type="submit" class="btn btn-primary">查询</button>
</form>
</div>
</label>
</div>
<table class="table table-bordered table-hover">
<thead>
<tr>
<th>序号</th>
<th>商品编号</th>
<th>商品名称</th>
<th>商品类别</th>
<th>价格</th>
<th>备注</th>
<th> </th>
</tr>
</thead>
<tbody>
<c:forEach items="${applicationScope.goods }" var="good"
varStatus="idx">
<tr>
<td>${idx.index + 1 }</td>
<td>${good.goodsId }</td>
<td>${good.goodsName }</td>
<td>${good.goodsType }</td>
<td style="color: red; font-weight: bold">￥<fmt:formatNumber
value="${good.price }" pattern="0,000.00"></fmt:formatNumber>
</td>
<td>${good.description }
</tr>
</c:forEach>
</tbody>
</table>
</div>
</div>
</div>
<!-- 表单 -->
<div class="modal fade" tabindex="-1" role="dialog" id="dlgForm">
<div class="modal-dialog" role="document">
<div class="modal-content">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal"
aria-label="Close">
<span aria-hidden="true">×</span>
</button>
<h4 class="modal-title">新增商品</h4>
</div>
<div class="modal-body">
<form action="/goods/create" method="post">
<div class="form-group">
<label>商品编号</label> <input type="text" name="goodsId"
class="form-control" id="empno" placeholder="请输入商品编号">
</div>
<div class="form-group">
<label>商品名称</label> <input type="text" name="goodsName"
class="form-control" id="ename" placeholder="请输入商品名称">
</div>
<div class="form-group">
<label>商品类别</label> <select id="gname" name="goodsType"
class="form-control">
<option value="服装">服装</option>
<option value="家用">家用电器</option>
<option value="生活">生活用品</option>
</select>
</div>
<div class="form-group">
<label>价格</label> <input type="text" name="price"
class="form-control" id="sal" placeholder="请输入价格">
</div>
<div class="form-group">
<label>备注</label> <input type="text" name="description"
class="form-control" id="sal" placeholder="请输入备注">
</div>
<div class="form-group" style="text-align: center;">
<button type="submit" class="btn btn-primary">保存</button>
</div>
</form>
</div>
</div>
<!-- /.modal-content -->
</div>
<!-- /.modal-dialog -->
</div>
<!-- /.modal -->
</body>
</html>searchById.jsp
<%@ page contentType="text/html; charset=utf-8"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width,initial-scale=1">
<title>商品信息</title>
<link href="css/bootstrap.css" type="text/css" rel="stylesheet">
</link>
<script type="text/javascript" src="js/jquery-1.11.1.min.js"></script>
<script type="text/javascript" src="js/bootstrap.js"></script>
<style type="text/css">
.pagination {
margin: 0px
}
.pagination>li>a, .pagination>li>span {
margin: 0 5px;
border: 1px solid #dddddd;
}
.glyphicon {
margin-right: 3px;
}
.form-control[readonly] {
cursor: pointer;
background-color: white;
}
#dlgPhoto .modal-body {
text-align: center;
}
.preview {
max-width: 500px;
}
</style>
</head>
<body>
<button class="btn btn-primary"
style="margin-left: 30px; margin-top: 40px;"
onclick="javascript:history.back(-1);">返回</button>
<div class="container">
<div class="row">
<h1 style="text-align: center">IMOOC商品信息表</h1>
<table class="table table-bordered table-hover">
<thead>
<tr>
<th>商品编号</th>
<th>商品名称</th>
<th>商品类别</th>
<th>价格</th>
<th>备注</th>
</tr>
</thead>
<tbody>
<tr>
<td>${applicationScope.searchGoods.goodsId }</td>
<td>${applicationScope.searchGoods.goodsName }</td>
<td>${applicationScope.searchGoods.goodsType }</td>
<td style="color: red; font-weight: bold">￥<fmt:formatNumber
value="${applicationScope.searchGoods.price }"
pattern="0,000.00"></fmt:formatNumber>
<td>${applicationScope.searchGoods.description }</td>
</tr>
</tbody>
</table>
</div>
</div>
</div>
</body>
</html>22
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1回答
同学你好，建议同学在遍历之前定义商品变量，表示查询到的商品信息。在遍历完成后判断一下商品变量是否为null。
在jsp界面中判断一下作用域中商品信息是否为null，如果为null，表示没有查询到商品，如果不为null，则展示商品信息。
查看代码如下：
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