input数量的加减

最新推荐文章于 2023-10-30 15:15:40 发布

南拥夏栀@北梦木兮

最新推荐文章于 2023-10-30 15:15:40 发布

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分类专栏： Java-Web

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该博客介绍了如何在Java Web应用中使用JSTL标签库处理数据，特别是通过`<c:forEach>`迭代Map对象。文章提到了需要导入jstl.jar和standard.jar，并展示了如何在Servlet中实现数据操作的相关代码。

1.有数据传递<%@taglib uri=“http://java.sun.com/jsp/jstl/core” prefix=“c”%>
2.记得导入jar包 jstl.jar /standard.jar
定义一个类ShopItem
package com.flowershop.entity;
public class ShopItem {

private int buyCount;
private Flower buyProduct ;
public int getBuyCount() {
	return buyCount;
}
public void setBuyCount(int buyCount) {
	this.buyCount = buyCount;
}
public Flower getBuyProduct() {
	return buyProduct;
}
public void setBuyProduct(Flower buyProduct) {
	this.buyProduct = buyProduct;
}
public ShopItem(int buyCount, Flower buyProduct) {
	super();
	this.buyCount = buyCount;
	this.buyProduct = buyProduct;
}

public ShopItem( Flower buyProduct) {

	this.buyCount =1;
	this.buyProduct = buyProduct;
}
public ShopItem() {
	super();
	// TODO Auto-generated constructor stub
}

}

<c:forEach items="${mapcar}" var=“entry” varStatus=“vs”>

3.package com.flowershop.servlet;

import java.io.IOException;
import java.util.HashMap;

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.flowershop.dao.FlowerDao;
import com.flowershop.entity.Flower;
import com.flowershop.entity.ShopItem;

/**

Servlet implementation class ChangeCart
*/
@WebServlet("/ChangCarServlet")
public class ChangCarServlet extends HttpServlet {
private static final long serialVersionUID = 1L;

/**

@see HttpServlet#HttpServlet()
*/
public ChangCarServlet() {
super();
// TODO Auto-generated constructor stub
}

/**

@see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
```
 response)
```

*/
protected void doGet(HttpServletRequest request,
HttpServletResponse response) throws ServletException, IOException {

 //实现购物车的数量
 response.setContentType("text/html;charset=utf-8");
 String id =request.getParameter("id");
 int idd=Integer.parseInt(id);

 System.out.println("id"+idd);
 
 //数量的类型转换
 String count = request.getParameter("count");
 int newCount = Integer.parseInt(count);

 HashMap<String, ShopItem> mapCar = (HashMap<String, ShopItem>) request
 		.getSession().getAttribute("mapcar");

 ShopItem item = mapCar.get(id);

 // 存map的值判断是否有购物车
 if (newCount == 0) {
 	mapCar.remove(id);
 } else {
 	//调整商品的数量
 	item.setBuyCount(newCount);
 }
 if(mapCar.size()==0){
 	request.getSession().removeAttribute("mapcar");
 	
 }
 request.getSession().setAttribute("mapcar", mapCar);
 response.sendRedirect("index/shoppingflowercart.jsp");

}
}