关于显示所有菜品出现500的问题!
<!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>菜品查询选项页面</title> <style type="text/css"> </style> </head> <body> <center> <p><a href="/manu/ShowFoodServlet">查询所有菜品信息</a></p> <p><a href="selectFoodByName.html">菜名查询</a></p> </center> </body> </html>
package servlet;
import java.io.IOException;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import domain.Food;
import utils.FoodDaoImpl;
/**
* 显示所有菜品servlet
*/
@WebServlet("/ShowFoodServlet")
public class ShowFoodServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//实例化取全部数据方法
FoodDaoImpl foodDaoImpl=new FoodDaoImpl();
//调用方法取出所有食物,存储到Food类的List列表里
List<Food>list=foodDaoImpl.getAllFood();
//存储到request的属性中
request.setAttribute("list", list);
request.getRequestDispatcher("/showFoodList.jsp").forward(request, response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
}<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>菜品信息展示</title>
<style type="text/css">
</style>
</head>
<body>
<center>
<h1>菜品查询</h1>
<table border="1px" cellspacing="0px" cellpadding="0px" width="800px">
<thead>
<tr>
<th>菜品ID</th>
<th>菜名</th>
<th>口味</th>
<th>菜品图片</th>
<th>价格</th>
<th>菜品描述</th>
</tr>
</thead>
<tbody>
<%
//直接读取从servlet传过来的request数据
List<Food> foodList = (List<Food>)request.getAttribute("list");
//判断如果这个list不为空,则循环输出所有数据,如果为空则提示.
for(Food food:foodList){
String id =food.getId ;
String name = food.getName;
String taste = food.getTaste;
String path = food.getPath;
String price = food.getPrice;
String info = food.getInfo;
%>
<tr>
<td><%=id %></td>
<td><%= %></td>
<td><%= %></td>
<td><img src="<%= %>"></td>
<td><%= %></td>
<td><%= %></td>
</tr>
<%
}
%>
</tbody>
</table>
</center>
</body>
</html>点查询所有菜单后出现500错误!菜品可以正常添加,显示所有菜品的方法是return db;
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4回答
龍彦宏
2019-01-22 11:11:20
再補充一下,现在做完搜索菜品也是500出错,不知道哪里出了问题.补上代码.
package utils;
import java.util.ArrayList;
import java.util.List;
import domain.Food;
/**
* 菜品处理类
*/
public class FoodDaoImpl {
//存放菜品List集合
private static final List<Food> db = new ArrayList<Food>();
//添加菜品
public void addFood(Food food){
db.add(food);
}
//显示所有菜品
public List<Food>getAllFood(){
return db;
}
//根据菜品名称查询菜品信息
public List<Food >getFoodByName(String foodName){
List<Food > foodList = new ArrayList<>();//创建一个list集合接收数据
Food getFood = null;
for(Food food : db){
if(food.getName().equals(foodName)){
getFood = food;
foodList.add(getFood);
}
}
return foodList ;
}
}<!DOCTYPE html> <html> <head> <base href="<%=basePath%>"> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>菜名查询</title> <style type="text/css"> </style> </head> <body> <center> <h1>菜名查询</h1> <form action="/manu/SelectServlet" method="post"> <input type="hidden" name="type" value="2"> <table width="400px" border="1px" cellspacing="0px" cellpadding="0px"> <tr> <td>菜名</td> <td><input type="text" name="name"></td> </tr> <tr> <td colspan="2" style="text-align:center"><input type="submit" value="查询"></td> </tr> </table> </form> </center> </body> </html>
package servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import domain.Food;
import utils.FoodDaoImpl;
/**
* 通过名称查询菜品名称
*/
@WebServlet("/SelectServlet")
public class SelectServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//从表单获取查询名称
String foodName = request.getParameter("name");
//实例化调取命令查询对应食物集合
FoodDaoImpl foodDaoImpl = new FoodDaoImpl();
Food food = (Food) foodDaoImpl.getFoodByName(foodName);
request.setAttribute("food",food);
request.getRequestDispatcher("/showFoodList2.jsp").forward(request, response);
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
}<%@ page import="java.util.List" %>
<%@ page import="domain.Food" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>菜品信息展示</title>
<style type="text/css">
</style>
</head>
<body>
<center>
<h1>菜品查询</h1>
<table border="1px" cellspacing="0px" cellpadding="0px" width="800px">
<thead>
<tr>
<th>菜品ID</th>
<th>菜名</th>
<th>口味</th>
<th>菜品图片</th>
<th>价格</th>
<th>菜品描述</th>
</tr>
</thead>
<tbody>
<%
List<Food> foodList = (List<Food>) request.getAttribute("list");
Food food = (Food)request.getAttribute("food");
if(food!=null){%>
<tr>
<td><%=food.getId()%></td>
<td><%=food.getName()%></td>
<td><%=food.getTaste()%></td>
<td><img src="<%=food.getPath()%>"></td>
<td><%=food.getPrice()%></td>
<td><%=food.getDescription()%></td>
</tr>
<% }else{
for (Food food1 : foodList) {%>
<tr>
<td><%=food1.getId()%></td>
<td><%=food1.getName()%></td>
<td><%=food1.getTaste()%></td>
<td><img src="<%=food1.getPath()%>"></td>
<td><%=food1.getPrice()%></td>
<td><%=food1.getDescription()%></td>
</tr>
<%}
}%>
</tbody>
</table>
</center>
</body>
</html>老师...我觉得自己做这个太困难了,没有教程对这种增删改查的,可否把后面的修改和删除的方法都铁给我...这块太耽误时间了,我得赶紧学后面的了.
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