Java servlet 实现的简易购物车
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2022-10-16 15:03:02
首页 2.购买页 3.购物车页 1. 首页代码 发送一个post请求 ......
首页
2.购买页
3.购物车页
1. 首页代码 发送一个post请求
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<title>首页</title>
</head>
<body>
<img src="/img/bookcover/shoping.png" alt="购物">
<form action="goshop.do" method="post">
<p>欢迎您</p><br>
<input type="submit" value="进入购物">
</form>
</body>
</html>
2.处理首页post请求的controler
package cc.openhome.controler;
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 java.io.ioexception;
import java.util.linkedhashmap;
@webservlet("/goshop.do")
public class goshop extends httpservlet {
void processrequest(httpservletrequest req,httpservletresponse resp)
throws servletexception,ioexception
{
bookdb bs = new bookdb();
linkedhashmap<string,book> books = bs.getall();
req.setattribute("books",books);
req.getrequestdispatcher("shop.view").forward(req,resp);
}
@override
protected void dopost(httpservletrequest req, httpservletresponse resp) throws servletexception, ioexception {
processrequest(req,resp);
}
@override
protected void doget(httpservletrequest req, httpservletresponse resp) throws servletexception, ioexception {
processrequest(req,resp);
}
}
3 ,展示购物页面
package cc.openhome.view;
import cc.openhome.controler.*;
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 javax.servlet.http.httpsession;
import java.io.ioexception;
import java.io.printwriter;
import java.util.linkedhashmap;
@webservlet("/shop.view")
public class shopview extends httpservlet {
protected void processrequest(httpservletrequest req, httpservletresponse resp) throws servletexception, ioexception {
resp.setcontenttype("text/html;charset=utf-8");
string bookid = req.getparameter("bookid");
int count = 0;
httpsession session = req.getsession();
// 在点击了购买之后书的数量在加一,否则只刷新
if(session.getattribute("count") != null && bookid != null){
integer c = (integer) session.getattribute("count");
count = c + 1;
}
session.setattribute("count",count);
//购物
cart cart = (cart) req.getsession().getattribute("cart");
if(cart == null){
cart = new cart();
req.getsession().setattribute("cart",cart);
}
businessservice bussiness = new businessservice();
if(count > 0){
bussiness.buybook(bookid,cart);
}
session.setattribute("cart",cart);
printwriter out = resp.getwriter();
out.println("<!doctype html public '-//w3c//dtd html 4.01'" +
"transitional//en");
out.println("<html>");
out.println("<head>");
out.println("<title>购物网页</title>");
out.println("</head>");
out.println("<body>");
out.println("<form action='' method='post'>");
out.println("<table width='100%'>");
out.println("<td><img src='img/bookcover/shop.png' alt='小购物车' width='50'>" +
"<a href='cart.view'>已采购"+count+"书籍</a><td>");
out.println("</table>");
out.println("<table width='100%'>");
out.println("<tr>");
out.println("<td style='color:blue'>书籍编号<td>");
out.println("<td style='color:blue'>书名<td>");
out.println("<td style='color:blue'>图片</td>");
out.println("<td style='color:blue'>价格<td>");
out.println("<td style='color:blue'>购买<td>");
out.println("</tr>");
int i = 0;
linkedhashmap <string,book> books = (linkedhashmap <string,book>) req.getattribute("books");
for (string value : books.keyset()){
i++;
book book = books.get(value);
out.println("<tr>");
out.println("<td>"+book.getid()+"<td>");
out.println("<td>"+book.getname()+"<td>");
out.println("<td><img src='/img/bookcover/book"+i+".jpeg'></td>");
out.println("<td>"+book.getprice()+"<td>");
out.println("<td><a href='"+resp.encodeurl("goshop.do")+"?bookid="+book.getid()+"'>购买此书</a><td>");
out.println("<tr>");
}
/*
int i,j = 0,k = 0;
int len = books.size();
for(i = 0;i < len; i++,j++,k++){
if(j % 3 == 0){
out.println("<tr>");
}
out.println("<td>");
out.println("<img src='/img/bookcover/book"+i+".jpeg'>");
out.println("</td>");
if(k % 3 == 0){
out.println("</tr>");
}
}
j = 0;
k = 0;
for( i = 0;i < len; i++,j++,k++){
if(j % 3 == 0){
out.println("<tr>");
}
out.println("<td>");
out.println("<a href='#'>购买此书</a>");
out.println("</td>");
if(k % 3 == 0){
out.println("</tr>");
}
}
*/
out.println("</table>");
out.println("</form>");
out.println("</body>");
out.println("</html>");
out.close();
}
@override
protected void doget(httpservletrequest req, httpservletresponse resp) throws servletexception, ioexception {
processrequest(req, resp);
}
@override
protected void dopost(httpservletrequest req, httpservletresponse resp) throws servletexception, ioexception {
processrequest(req, resp);
}
}
4.购物车页面
package cc.openhome.controler;
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 javax.servlet.http.httpsession;
import java.io.ioexception;
import java.io.printwriter;
import java.util.map;
@webservlet("/cart.view")
public class cartshow extends httpservlet {
public void processrequest(httpservletrequest req, httpservletresponse resp)
throws servletexception, ioexception
{
resp.setcontenttype("text/html;charset=utf-8");
httpsession session = req.getsession();
cart carts = (cart) session.getattribute("cart");
printwriter out = resp.getwriter();
out.println("<!doctype html public '-//w3c//dtd html 4.01'" +
"transitional//en");
out.println("<html>");
out.println("<head>");
out.println("<title>购物结算</title>");
out.println("</head>");
out.println("<body>");
out.println("<form action='' method='post'>");
out.println("<table width='100%'>");
out.println("<td><img src='img/bookcover/shoping.png' alt='购物车' width='100'>");
out.println("</table>");
out.println("<table width='100%'>");
out.println("<tr>");
out.println("<td style='color:blue'>书籍编号<td>");
out.println("<td style='color:blue'>书名<td>");
out.println("<td style='color:blue'>图片</td>");
out.println("<td style='color:blue'>单价<td>");
out.println("<td style='color:blue'>数量<td>");
out.println("<td style='color:blue'>单本书总价<td>");
out.println("</tr>");
int i = 0;
map<string,cartitem> bookmap = carts.getbookmap();
for (string value : bookmap.keyset()){
i++;
cartitem citem = bookmap.get(value);
book bk = citem.getbook();
out.println("<tr>");
out.println("<td>"+bk.getid()+"<td>");
out.println("<td>"+bk.getname()+"<td>");
out.println("<td><img src='/img/bookcover/book"+i+".jpeg'></td>");
out.println("<td>"+bk.getprice()+"<td>");
out.println("<td>"+citem.getquantity()+"<td>");
out.println("<td>"+citem.getprice()+"<td>");
out.println("</tr>");
}
out.println("<tr>");
out.println("<td style='color:green';font-size:200%'>总价</td>");
out.println("<td style='color:green';font-size:200%'> "+carts.getprice()+"</td>");
out.println("</tr>");
out.println("</table>");
out.println("</form>");
out.println("</body>");
out.println("</html>");
out.close();
}
@override
protected void dopost(httpservletrequest req, httpservletresponse resp) throws servletexception, ioexception {
processrequest(req, resp);
}
@override
protected void doget(httpservletrequest req, httpservletresponse resp) throws servletexception, ioexception {
processrequest(req, resp);
}
}
5,书籍类
package cc.openhome.controler;
import java.util.arraylist;
public class book {
private string id;
private string name;
private double price;
public book(){
}
public book(string id,string name, double price){
this.id = id;
this.name = name;
this.price = price;
}
public string getid() {
return id;
}
public string getname() {
return name;
}
public double getprice() {
return price;
}
}
6,单个购物车类
package cc.openhome.controler;
public class cartitem {
private book book;
private int quantity;
private double price;
public double getprice() {
return book.getprice() * this.quantity;
}
public book getbook() {
return book;
}
public void setbook(book book) {
this.book = book;
}
public int getquantity() {
return quantity;
}
public void setquantity(int quantity) {
this.quantity = quantity;
}
public void setprice(double price) {
this.price = price;
}
}
7,购物车类
package cc.openhome.controler;
import java.util.linkedhashmap;
import java.util.map;
public class cart {
private map<string,cartitem> bookmap = new linkedhashmap<>();
private double price;
public void addbook(book book){
cartitem cartitem = bookmap.get(book.getid());
if(cartitem == null){
cartitem = new cartitem();
cartitem.setbook(book);
cartitem.setquantity(1);
bookmap.put(book.getid(),cartitem);
}else {
cartitem.setquantity(cartitem.getquantity() + 1);
}
}
public double getprice() {
double totalprice = 0;
for(map.entry<string,cartitem> me : bookmap.entryset()){
cartitem cartitem = me.getvalue();
totalprice += cartitem.getprice();
}
return totalprice;
}
public map<string, cartitem> getbookmap() {
return bookmap;
}
public void setbookmap(map<string, cartitem> bookmap) {
this.bookmap = bookmap;
}
public void setprice(double price) {
this.price = price;
}
}
8图书数据源
package cc.openhome.controler;
import java.util.linkedhashmap;
public class bookdb {
private linkedhashmap<string,book> map = new linkedhashmap<>();
public bookdb(){
map.put("1",new book("1","java编程",10.00));
map.put("2",new book("2","c++编程",10.00));
map.put("3",new book("3","c编程",10.00));
}
public linkedhashmap<string,book> getall(){
return map;
}
public book findbook(string id){
return map.get(id);
}
}
总结:对于个人而言:难点在于
1.页面数据的展示.
2.使用resp.encodeurl 在本页面刷新.
3.使用<a href> 重定向并且带了一个参数,把书的id发送给本页面处理.
4.http session 来存储发送数据.
5.书籍,购物车类的设计.
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