cartaction.java

java学习的必要的资料,servlet的说明很好

package com.estore.struts.action;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.actions.DispatchAction;

import com.estore.struts.Globals;
import com.estore.struts.entity.Cart;
import com.estore.struts.entity.CartProduct;
import com.estore.struts.entity.Product;
import com.estore.struts.entity.User;
import com.estore.struts.service.ProductService;
import com.estore.struts.utils.ServiceFactory;

public class CartAction extends DispatchAction {

	public ActionForward addCart(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
		
		/*
		 * 在添加商品之前，会对session和user进行判断，如果不存在时，会把错误信息封装到request中，
		 * 然后转发出去让用户重新登录；
		 */
		HttpSession session = request.getSession(false);
		String message = "";
		if (session == null) {
			message = "该Session已经过期,或者你没有登录,请重新<a href='/estore/pages/login.jsp' style='color:red;'>登录</a>!请<a onclick='javascript:history.go(-1)' style='color:red;'>返回</a>!";
			request.setAttribute("message", message);
			return mapping.findForward("error");
		}
		User user = (User) session.getAttribute("user");
		if (user == null) {
			message = "该Session已经过期,或者你没有登录,请重新<a href='/estore/pages/login.jsp' style='color:red;'>登录</a>! 请<a onclick='javascript:history.go(-1)' style='color:red;'>返回</a>";
			request.setAttribute("message", message);
			return mapping.findForward("error");
		}
		/*
		 * 从session中获得购物车
		 */
		Cart cart = (Cart) session.getAttribute("cart");
		if (cart == null) {
			cart = new Cart();
		}
		/*
		 * 从数据库中把商品取到；
		 */
		ProductService productService = (ProductService) ServiceFactory
				.getInstance().getService(Globals.PRODUCT_SERVICE);
		
		Integer id = Integer.parseInt(request.getParameter("productid"));

		Product product = productService.getProductById(id);
		
		/*
		 * 在向购物车中添加商品的时候会判断商品是否已经存在，
		 * 已存在的就不让在加入了；
		 */
		if (cart.isExist(id)) {
			message = "该商品已经存在!请<a onclick='javascript:history.go(-1)'>返回</a>!";
			request.setAttribute("message", message);
			return mapping.findForward("error");
		} else {
			/*
			 * 向购物车添加一个商品；
			 */
			cart.addCart(product);
			session.setAttribute("cart", cart);
			return mapping.findForward("addcartsuccess");
		}
	}

	public ActionForward remove(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
		
		HttpSession session = request.getSession();
		Integer productid = Integer.parseInt(request.getParameter("productid"));
		ProductService productService = (ProductService) ServiceFactory
		.getInstance().getService(Globals.PRODUCT_SERVICE);
		Product pro = productService.getProductById(productid);
		Cart cart = (Cart) session.getAttribute("cart");
		cart.removeCart(pro);
		session.setAttribute("cart", cart);
		return mapping.findForward("removecartsuccess");
	}

	public ActionForward modify(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
		
		Integer productid=Integer.parseInt(request.getParameter("productid"));
		int num=Integer.parseInt(request.getParameter("num"));
		
		HttpSession session = request.getSession();
		Cart cart = (Cart) session.getAttribute("cart");
		cart.modifyNum(productid, num);
		
		return  mapping.findForward("modifycartsuccess");
	}
	
	/*
	 * 也就是从session中把购物车清除掉；
	 */
	public ActionForward removeall(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response)
			throws Exception {
		
		HttpSession session = request.getSession();
		Cart cart = (Cart) session.getAttribute("cart");
		session.removeAttribute("cart");
		return mapping.findForward("success");
	}

}