Detailed description of the shopping cart program compiled using the JSP Session mechanism

A program written using the JSP Session mechanism can be a shopping cart program with powerful functions. Is it very attractive? Let's get started with our program.

Product class constructed in one of the JSP Session mechanism shopping cart

◆ Write a Goods class, define the attributes of the product, return the methods of the product attributes, and compare the product objects.

◆ Goods. java

 
 

  
  
package com.viita.Shop;  
  
  
 
  
  
public class Goods implements Comparable {  
  
  
 
 
 

◆ Initialize member variables

 
 

  
  
Private StringId=Null; // Product Id
  
  
Private StringName=Null; // Product name
  
  
Private floatPrice=0. 00F; // price of the product
  
  
Private intNumber=0; // Number of items
  
  
Public Goods (String Id, String name, float price, int number ){
  
  
This. Id= Id;
  
  
This. name= Name;
  
  
This. price= Price;
  
  
This. number= Number;
  
  
 
  
  
}
  
  
Public String getId () // return the Id of the purchased item
  
  
{
  
  
Return this. Id;
  
  
}
  
  
Public String getName () // return the name of the purchased item
  
  
{
  
  
Return this. name;
  
  
}
  
  
Public float getPrice () // returns the price of the purchased item
  
  
{
  
  
Return this. price;
  
  
}
  
  
Public int getNumber () // returns the number of purchased items
  
  
{
  
  
Return this. number;
  
  
}
  
  
Public int compareTo (Object m ){
  
  
// TODO Auto-generated method stub
  
  
 
  
  
GoodsN= (Goods) m;
  
  
IntComRs=Id. CompareTo (n. Id );
  
  
Return comRs;
  
  
 
  
  
}
  
  
 
  
  
}
  
  
 
 
 

JSP Session mechanism shopping cart II shopping cart implementation

◆ Create Goods (product) object goods and create an ArrayList object ay

◆ Add () the item object to the ArrayList object ay using the ArrayList object Method

◆ Because the ArrayList object has a method to add and delete members, multiple product storage can be managed on the ArrayList object.

◆ Store the ArrayList object ay in the session object to implement the shopping cart function.

◆ Shopcar. jsp

 
 

  
  
<%@ page language="java" import=" java.sql.*,com.viita.Shop.*,java.util.*" pageEncoding="GBK"%> 
  
  
<%  
  
  
 
 
 

◆ Set the encoding format

 
 

  
  
request.setCharacterEncoding("GBK");  
  
  
 
 
 

◆ Obtain parameter information

 
 

  
  
String id = request.getParameter("id");  
  
  
String name = request.getParameter("name");  
  
  
int number = java.lang.Integer.parseInt(request.getParameter("number"));  
  
  
float price= java.lang.Float.parseFloat(request.getParameter("price")); 
 
 

◆ Create product objects and ArrayList objects

 
 

  
  
Goods goods = new Goods(id,name,price,number);  
  
  
ArrayList ay = null; 
 
 

◆ If the session has never been written, add the created item object to the ArrayList object and write it to the session.

 
 

  
  
if((ArrayList)session.getAttribute("car")==null)  
  
  
{  
  
  
ay = new ArrayList();  
  
  
ay.add(goods);  
  
  
session.setAttribute("car",ay);  
  
  
response.sendRedirect("order_index.jsp");  
  
  
} 
 
 

◆ If it has been written, add the product object to the ArrayList object and write it to the session.

 
 

  
  
else  
  
  
{  
  
  
ay=(ArrayList)session.getAttribute("car"); 
 
 

◆ If the ArrayList object is empty, it is directly added to the ArrayList object.

 
 

  
  
if(ay.isEmpty())  
  
  
{  
  
  
ay.add(goods);  
  
  
session.setAttribute("car",ay);  
  
  
response.sendRedirect("order_index.jsp");  
  
  
} 
 
 

◆ If the ArrayList object is not empty, determine whether the purchased product already exists in the vehicle.

 
 

  
  
Else
  
  
{
  
  
IteratorIt=Ay. Iterator ();
  
  
For (intI=0; I<Ay. size(); I ++) // There is another Traversal method below
  
  
{
  
  
GoodsShop= (Goods) it. next ();
 
 

◆ If the purchased product already exists, print the input prompt.

 
 

  
  
If (shop. compareTo (goods) = 0)
  
  
{
  
  
Out. println ("<Script>Alert ('you have purchased this item! '); Window. close (); Script>");
  
  
}
 
 

◆ If the purchased item does not exist, add the item to the ArrayList object and write it to the session.

 
 

  
  
else  
  
  
{  
  
  
ay.add(goods);  
  
  
session.setAttribute("car",ay);  
  
  
response.sendRedirect("order_index.jsp");  
  
  
}  
  
  
}  
  
  
}  
  
  
}   
  
  
%> 
 
 

JSP Session mechanism shopping cart 3 Delete items

◆ Delete the items in the shopping cart

◆ RemoveGoods. jsp

 
 

  
  
<%@ page language="java" import="java.sql.*,com.viita.Shop.*,java.util.*" pageEncoding="GBK"%> 
  
  
<%  
 
 

◆ Set the encoding format

 
 

  
  
request.setCharacterEncoding("gb2313"); 
 
 

◆ Obtain parameter information

 
 

  
  
String id = request.getParameter("id");  
  
  
String name = request.getParameter("name");  
  
  
float price = java.lang.Float.parseFloat(request.getParameter("price"));  
  
  
int number = java.lang.Integer.parseInt(request.getParameter("number")); 
 
 

◆ Create a commodity object that meets the condition parameters to be deleted

 
 

  
  
Goods goods = new Goods(id,name,price,number); 
 
 

◆ Get the ArrayList object stored in the session

 
 

  
  
ArrayList ay = (ArrayList)session.getAttribute("car");  
  
  
Iterator it = ay.iterator(); 
 
 

◆ Traverse the ArrayList object and compare the elements in the ArrayList object with the created items that meet the parameter conditions to be deleted

 
 

  
  
for(int i = ay.size();it.hasNext();i--)  
  
  
{  
  
  
Goods shop = (Goods)it.next(); 
 
 

◆ Check whether ArrayList objects have the same elements as the items to be deleted.

 
 

  
  
if(shop.compareTo(goods)==0)  
  
  
{  
  
  
int index = ay.indexOf(shop);  
 
 

◆ If the ArrayList object is already empty, jump

 
 

  
  
if(ay.isEmpty())  
  
  
{  
  
  
response.sendRedirect("order_index.jsp");  
  
  
} 
 
 

◆ If the ArrayList object is not empty, the elements that match the condition of the item to be deleted are removed from it, and the session is rewritten.

 
 

  
  
Else
  
  
{
  
  
Ay. remove (index );
  
  
Session. setAttribute ("car", ay );
  
  
Response. sendRedirect ("order_index.jsp ");
  
  
}
  
  
}
  
  
Else
  
  
{
  
  
Out. print ("program exception ");
  
  
}
  
  
}
  
  
%> 
 
 

Does the JSP Session mechanism's shopping cart make your eyes shine suddenly? Let's get started. We look forward to your attempt to use the JSP Session mechanism.

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