Java web development shopping cart function implementation, java shopping cart

Java web development shopping cart function implementation, java shopping cart

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Since it is a shopping cart, the precondition is that a series of products are required first, that is, to create an entity. Here a commodity table is created,

Display on the browser by querying

The basic display is ready. Now we are playing a major role, Servlet

When you click "add to shopping cart", the access Servlet

Shopping Cart code

1 package com. servlet; 2 3 import java. io. IOException; 4 import java. io. printWriter; 5 import java. util. hashMap; 6 import java. util. map; 7 8 import javax. servlet. servletException; 9 import javax. servlet. http. httpServlet; 10 import javax. servlet. http. httpServletRequest; 11 import javax. servlet. http. httpServletResponse; 12 13 import com. dao. goodsDAO; 14 import com. entity. goods; 15 import com. entity. goodsItem; 16 17 public class PutCarServlet extends HttpServlet {18 19 public void doGet (HttpServletRequest request, HttpServletResponse response) 20 throws ServletException, IOException {21 22 response. setContentType ("text/html"); 23 PrintWriter out = response. getWriter (); 24 25 doPost (request, response); 26} 27 28 public void doPost (HttpServletRequest request, HttpServletResponse response) 29 throws ServletException, IOException {30 31 response. setContentType ("text/html"); 32 PrintWriter out = response. getWriter (); 33 // get id 34 String id = request. getParameter ("goodsID"); 35 36 // obtain all information of the commodity object by serial number 37 GoodsDAO dao = new GoodsDAO (); 38 Goods g = dao. getGoodsByID (id); 39 // put the item into the shopping cart 40 41 // map set is the shopping cart 42 // map <key, value> item number as key item as value 43 44 // 1. determine whether a shopping cart exists. 45 // The shopping cart is placed in the session. 46 // The shopping cart is retrieved from the session. 47 Map <String, GoodsItem> gwc = (Map <String, GoodsItem>) request. getSession (). getAttribute ("gwc"); 48 // determine whether 49 if (gwc = null) {50 // create a shopping cart 51 gwc = new HashMap <String, GoodsItem> (); 52} 53 54 // Add the item to the shopping cart 55 // put (item number, item) add data to the gwc set 56 // you want to check whether the item already exists in the shopping cart 57 // to put it bluntly, match whether such item exists in the gwc set = set match whether there is such a product number key58 59 // determine whether there is a product number key 60 61 if (gwc. containsKey (id )) {62 // 63 // set quantity + 164 65 // obtain the value 66 through the key // The key is the product number value. The item contains the product object information and quantity information. 67 GoodsItem spx = gwc. get (id); 68 // obtain the original number of 69 int yldsl = spx. getCount (); 70 // In the original number + 171 gwc. get (id ). setCount (yldsl + 1); 72 73 // gwc. get (id ). setCount (gwc. get (id ). getCount () + 1); 74 75} else {76 // No 77 // create a new item quantity of 178 GoodsItem gi = new GoodsItem (g, 1 ); 79 80 // add this item to gwc81 gwc. put (id, gi); 82} 83 84 // put the cart in session85 request. getSession (). setAttribute ("gwc", gwc); 86 87 // continue shopping 88 response. sendRedirect ("index. jsp "); 89} 90 91}

Execution result: