Java Online Book Mall (4) Shopping cart module 1_java

This example for you to share the shopping cart module of the specific code for your reference, the specific contents are as follows

It's not a session, it's not a cookie, it's a table

> Add Shopping items
> Modify the number of shopping items
> Delete Entry
> Bulk deletion of entries
> My shopping cart, that is, by user query entries
> Check the entries

1. Data table

Copy Code code as follows:

Insert INTO ' t_cartitem ' (' Cartitemid ', ' quantity ', ' Bid ', ' uid ', ' by ') VALUES (' b8939fc55131469cab11e3924d40185b ') , 1, ' ce01f15d435a4c51b0ad8202a318dca7 ', ' xxx ', 11;

2.CartItem

public class Cartitem {
 private String cartitemid;//primary key
 private int quantity;//number
 private book book;//entry corresponding figure Book
 private user user;//member
 
 //Add Subtotal method public
 double Getsubtotal () {/*
 * * Use BigDecimal without error
 * Requires that you must use the String type constructor
 /BigDecimal B1 = new BigDecimal (Book.getcurrprice () + "");
 BigDecimal b2 = new BigDecimal (quantity + "");
 BigDecimal B3 = b1.multiply (B2);
 return B3.doublevalue ();
 }

 Public String Getcartitemid () {return
 cartitemid;
 }

 public void Setcartitemid (String cartitemid) {
 this.cartitemid = Cartitemid;
 }

 public int getquantity () {return
 quantity;
 }

 public void setquantity (int quantity) {
 this.quantity = quantity;
 }

 Public book GetBook () {return book
 ;
 }

 public void Setbook (book book) {
 this.book = Book;
 }

 Public User GetUser () {return
 user;
 }

 public void SetUser (user user) {
 this.user = user
 }
}

Small tips: Rounding BigDecimal in Java does not have errors

Add Subtotal method public
double Getsubtotal () {/
 * * * use BigDecimal without error
 * requires that you must use a String type constructor
 . BigDecimal B1 = new BigDecimal (Book.getcurrprice () + "");
 BigDecimal b2 = new BigDecimal (quantity + "");
 BigDecimal B3 = b1.multiply (B2);
 return B3.doublevalue ();
}
 

3. Search Cart entry via user

Each entry in my Cart entry needs to display the price of the book's picture, which means that multiple table queries are required.

Public list<cartitem> Findbyuser (string uid) throws SQLException {
 String sql = ' SELECT * from T_cartitem C, t_ Book B where C.bid=b.bid and uid=? ORDER by C.orderby ";
 list<map<string,object>> maplist = qr.query (sql, New Maplisthandler (), UID);
 Return Tocartitemlist (maplist);
}

4. Add Shopping cart Entry----increase

Jsp

<div class= "Divform" >
 <form id= "Form1" action= "<c:url value= '/cartitemservlet '/>" method= "POST" >
 <input type= "hidden" name= "method" value= "Add"/> <input type= "hidden" "name="
 bid "value=" ${ Book.bid} "/>
 I want to buy: <input id=" cnt style= "Width:40px;text-align:center" type= "text" name= "Quantity" value= "1"/> pieces
 </form>
 <a id= "btn" href= "javascript:$" (' #form1 '). Submit (); " ></a>
</div>

Cartitemservlet

Public String Add (httpservletrequest req, HttpServletResponse resp)
 throws Servletexception, IOException {
 /*< c3/>* 1. Encapsulates the form data to Cartitem (bid, quantity)
 /
 Map map = Req.getparametermap ();
 Cartitem Cartitem = Commonutils.tobean (map, cartitem.class);
 Book book = Commonutils.tobean (map, book.class);
 User user = (user) req.getsession (). getattribute ("Sessionuser");
 Cartitem.setbook (book);
 Cartitem.setuser (user);
 Cartitemservice.add (cartitem);
 Return Mycart (req, resp);
}

Cartitemservice

public void Add (Cartitem cartitem) {
 try {
 * * * 1. Use UID and bid to query the database for the existence of this entry
 * *
 cartitem _cartitem = Cartitemdao.findbyuidandbid (
 cartitem.getuser (). Getuid (),
 Cartitem.getbook (). Getbid ());
 if (_cartitem = null) {//If there is no such entry, add the entry
 Cartitem.setcartitemid (Commonutils.uuid ());
 Cartitemdao.addcartitem (Cartitem);
 } else {//If this entry originally existed, modify the quantity
 //Use the original quantity and the number of new entries to make the new quantity
 int quantity = Cartitem.getquantity () + _ Cartitem.getquantity ();
 Modify the number of this old entry
 cartitemdao.updatequantity (_cartitem.getcartitemid (), quantity);
 }
 catch (Exception E) {
 throw new RuntimeException (e);
 }
}

Cartitemdao

public void Addcartitem (Cartitem cartitem) throws SQLException {
 String sql = ' INSERT into T_cartitem (Cartitemid, Quan tity, bid, UID) "+
 " values (?,?,?,?) ";
 Object[] params = {Cartitem.getcartitemid (), cartitem.getquantity (),
 Cartitem.getbook (). Getbid (), Cartitem.getuser (). Getuid ()};
 Qr.update (sql, params);

5. Shopping Cart module page javascript----check

Calculate totals

Add Click event to select All

Add the Click event to the check boxes for all entries

Add a click event to a minus sign

Add the Click event to the plus sign

Bulk Delete

list.jsp

<%@ page language= "java" import= "java.util.*" pageencoding= "UTF-8"%> <%@ taglib prefix= "C" uri= "http://" Java.sun.com/jsp/jstl/core "%> <%@ taglib prefix=" FN "uri=" http://java.sun.com/jsp/jstl/functions "%> <! DOCTYPE HTML PUBLIC "-//w3c//dtd HTML 4.01 transitional//en" >  

tips:js in rounded round.js

5. Displays the totals on the total element
$ ("#total"). Text (Round (total, 2));//round () function is to retain the sum of 2 bits

6. Bulk deletion function----Delete

Jsp

function Batchdelete () {
 //1. Gets the checkbox//2 for all selected entries.
 creates an array that adds the values of all selected checkboxes to the array
 //3. Specifies location as Cartitemservlet, parameter method=batchdelete, parameter cartitemids= array's tostring ()
 var cartitemidarray = new Array () ;
 $ (": Checkbox[name=checkboxbtn][checked=true]"). each (the function () {
  Cartitemidarray.push ($ (this). Val ());// Add the value of the check box to the array
 });
 Location = "/goods/cartitemservlet?method=batchdelete&cartitemids=" + Cartitemidarray;
}

Delete a

if (quantity = 1) {
 if (confirm) ("Do you really want to delete this entry?") ")) {
  location ="/goods/cartitemservlet?method=batchdelete&cartitemids= "+ ID;
 }
} else {
 

7. Revise quantity----change　

Jsp

Request server, modify quantity.
function sendupdatequantity (ID, quantity) {
 $.ajax ({
 async:false,
 cache:false,
 URL: "/goods/ Cartitemservlet ",
 data:{method:" Updatequantity ", cartitemid:id,quantity:quantity},
 type:" POST "
 , DataType: "JSON",
 success:function (result) {
 //1. Modify Quantity
 $ ("#" + ID + "Quantity"). Val (result.quantity);
 2. Modify Subtotal
 $ ("#" + ID + "Subtotal"). Text (result.subtotal);
 3. Recalculate totals
 showtotal ();}
 }
 );

Servlet

Public String updatequantity (httpservletrequest req, HttpServletResponse resp)
 throws Servletexception, IOException {
 String cartitemid = Req.getparameter ("Cartitemid");
 int quantity = Integer.parseint (Req.getparameter ("Quantity"));
 Cartitem Cartitem = cartitemservice.updatequantity (cartitemid, quantity);
 
 Returns a JSON object to
 the client StringBuilder sb = new StringBuilder ("{");
 Sb.append ("\" quantity\ ""). Append (":"). Append (Cartitem.getquantity ());
 Sb.append (",");
 Sb.append ("\" Subtotal\ ""). Append (":"). Append (Cartitem.getsubtotal ());
 Sb.append ("}");
 
 Resp.getwriter (). print (SB);
 return null;
}

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