菜品添加功能实现了,修改删除和查询有问题

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1.老师我接收数据的方法写在一个java类里,这样有什么问题吗?
2.菜品修改功能点击修改之后,页面跳转到一个白页,是是因为共用这个接收数据的方法有问题吗?还是FoodDaolpml这个类里面的bd集合不是同一个,所以修改的时候里面没有所以出现白页?或者是其他什么原因?
3.点击删除和根据菜品名称查询,页面重定向都不成功,跳转到一个白页
package com.imooc.food.utiles;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import com.imooc.food.Food;
public class UploadFileData {
 /**
  * 文件的数据接收类
  * @throws IOException 
  */
 public static Food UploadFile(HttpServletRequest request) throws IOException{
  String url=null;
  //定义一个Map集合用于保存接收到的数据
  Map<String ,String>map =new HashMap<String ,String>();
  //创建一个磁盘文件项工厂对象
  DiskFileItemFactory diskFileItemFactory =new DiskFileItemFactory();
  //创建一个核心解析类
  ServletFileUpload servletFileUpload =new ServletFileUpload(diskFileItemFactory);
  //解析request请求,返回的是List集合,集合中存放的是FileItem对象
  List<FileItem> list;
  try {
   list = servletFileUpload.parseRequest(request);
   //遍历集合,获得每个FileItem,判断是表单项还是文件上传项
   for (FileItem fileItem : list) {
    if (fileItem.isFormField()) {
     String name=fileItem.getFieldName();
     String value =fileItem.getString("UTF-8");
     System.out.println(name +"    " +value);
     map.put(name,value);
    }else{
     //文件上传项
     //文件上传功能
     //获得上传文件的名称
     String FileName =fileItem.getName();
     //通过工具类获得唯一文件名
     String uuidFileName = UploadUtils.getUUIDFileName(FileName);
     //获得文件上传数据
     InputStream is = fileItem.getInputStream();
     //获得文件上传的路径
     String path =request.getServletContext().getRealPath("/upload");
     //将输入流对接到输出流
     url =path + "\\"  + uuidFileName;
      
     OutputStream os = new FileOutputStream(url);
      
     int len = 0;
     byte[] b = new byte[1024];
     while((len = is.read(b))!= -1){
      os.write(b, 0, len);
     }
     is.close();
     os.close();
    }
   }
  } catch (FileUploadException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  System.out.println(map);
  Food food=new Food();
  food.setId(map.get("id"));
  food.setName(map.get("foodName"));
  food.setPrice(map.get("price"));
  food.setDescribe(map.get("describe"));
  food.setTaste(map.get("taste"));
  food.setFoodAdress(url);
  return food;
  }
}
  
 
package com.imooc.food.servlet;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
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 org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.FileUploadException;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
import com.imooc.food.Food;
import com.imooc.food.FoodDaolmpl;
import com.imooc.food.utiles.UploadFileData;
import com.imooc.food.utiles.UploadUtils;
/**
 * 菜品添加的Servlet
 */
@WebServlet("/FoodAddServlet")
public class FoodAddServlet extends HttpServlet {
 protected void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  // 数据的接收
  Food food = UploadFileData.UploadFile(request);
  FoodDaolmpl.addFood(food);
  // 添加成功,跳转到查询页面
  response.sendRedirect(request.getContextPath() + "/showFoodList.jsp");
 }
 /**
  * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
  *      response)
  */
 protected void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  // TODO Auto-generated method stub
  doGet(request, response);
 }
}
 
 
package com.imooc.food.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 com.imooc.food.Food;
import com.imooc.food.FoodDaolmpl;
import com.imooc.food.utiles.UploadFileData;
/**
 * Servlet implementation class FoodUpdateServlet
 */
@WebServlet("/FoodUpdateServlet")
public class FoodUpdateServlet extends HttpServlet {
  
 protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  Food food=UploadFileData.UploadFile(request); 
  FoodDaolmpl.updateFood(food);
   
  //修改成功,跳转到查询页面
  response.sendRedirect(request.getContextPath()+"/showFoodList.jsp");
 }
 /**
  * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
  */
 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  // TODO Auto-generated method stub
  doGet(request, response);
 }
}

package com.imooc.food.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 com.imooc.food.Food;
import com.imooc.food.FoodDaolmpl;

/**
* Servlet implementation class SelectServlet
*/
@WebServlet("/SelectServlet")
public class SelectServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  String name =request.getParameter("foodName");
  Food food =FoodDaolmpl.getFoodByName(name);
  request.setAttribute("food", food);

  //查询成功,返回到查询界面
  response.sendRedirect(request.getContextPath()+"/showFoodList.jsp");
}

/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}

}

package com.imooc.food.servlet;

import com.imooc.food.Food;
import com.imooc.food.FoodDaolmpl;

/**
* Servlet implementation class FoodDeleteServlet
*/
@WebServlet("/FoodDeleteServlet")
public class FoodDeleteServlet extends HttpServlet {

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
  String id =request.getParameter("id");
  for (Food food : FoodDaolmpl.getAllFood()) {
   if(food.getName().equals("id")){
    FoodDaolmpl.deleteFoodById(id);
    request.getRequestDispatcher("/showFoodList.jsp").forward(request, response);
   }else{
    request.getRequestDispatcher("/showFoodList.jsp").forward(request, response);
   }
  }
}

}

造梦大师 2019-03-27

源自：项目：登录注册功能 5-2 作业题

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2回答

提问者造梦大师 2019-03-28 15:11:39

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
 <%@ page import="com.imooc.food.*"%> 
 <%
    String path = request.getContextPath(); //path是project的名字
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<base href="<%=basePath%>">
<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>
    <%
     for(Food food:FoodDaolmpl.getAllFood()){
    %>
     <tr>
      <td><%=food.getId() %></td>
      <td><%=food.getName() %></td>
      <td><%=food.getTaste() %></td>
      <td><img src="<%=basePath%>upload/<%=food.getFoodAdress().substring(food.getFoodAdress().lastIndexOf("\\")+1) %>" /></td>
      <td><%=food.getPrice() %></td>
      <td><%=food.getDescribe() %></td>
     </tr>
    <%
     }
    %>
   </tbody>
  </table>
 </center>
</body>
</html>

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chrismorgen #1

你好同学，我在这个问答中回复你了，http://class.imooc.com/course/qadetail/103318，祝学习愉快~

2019-03-28 18:23:39

chrismorgen 2019-03-28 14:50:47

1、你这么写是没有问题的。

2、同学重定向之后是指showFoodList.jsp页面为空白页吗？建议同学使用转发试试，如果问题没有解决，建议你将showFoodList.jsp页面的代码也粘贴上来，只有产看了你具体的逻辑才能找出原因，祝学习愉快~

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提问者造梦大师 #1

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@ page import="com.imooc.food.*"%> <% String path = request.getContextPath(); //path是project的名字 String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <base href="<%=basePath%>"> <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> <% for(Food food:FoodDaolmpl.getAllFood()){ %> <tr> <td><%=food.getId() %></td> <td><%=food.getName() %></td> <td><%=food.getTaste() %></td> <td><img src="<%=basePath%>upload/<%=food.getFoodAdress().substring(food.getFoodAdress().lastIndexOf("\\")+1) %>" /></td> <td><%=food.getPrice() %></td> <td><%=food.getDescribe() %></td> </tr> <% } %> </tbody> </table> </center> </body> </html>

2019-03-28 15:11:11