关于显示所有菜品出现500的问题!
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 | <!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 > |
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 | 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); } } |
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 | <%@ 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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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.
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 | 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 ; } } |
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 | <!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 > |
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 | 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); } } |
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 | <%@ 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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