buyservlet.java

JSP版的网上书店系统

package shop;

import java.io.IOException;
import java.util.Vector;


import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public final class BuyServlet extends HttpServlet{  
	
	public BuyServlet(){
		super();
	}
	
	public void init(ServletConfig config)throws ServletException{
		super.init(config);
	}
	
	public void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {      
		 HttpSession session = req.getSession();
		 if(session==null){
				System.out.println("no session");
				System.exit(1);	
			}
		 
		 //通过request对象得到属性“productId”的值
		Integer productId = (Integer)req.getAttribute("productId");
		
        shop sp=new shop();
        DB db=new DB();
		ShopCart shopcart = new ShopCart();
		String PageForward;
		boolean b=false;
   		Vector shopCartList=(Vector)session.getAttribute(Constants.SHOPCART_KEY);
		if (shopCartList==null) {
			shopCartList = new Vector();
		}
		
		//判断选定商品是否已经加入购物车
		
    	if(shopCartList != null ){
       		for(int i = 0;i < shopCartList.size();i++){
       			shopcart = (ShopCart)shopCartList.get(i);
     			if (shopcart.getProduct().getId()==productId.intValue()){
     				b=true;
     			}
     		}
     	}
		
		//将选定商品加入购物车
		
		if (!b){
			Product product=null;
				try {
					product=sp.getProduct(db, productId.intValue());
				} catch (Exception e) {
					// TODO 自动生成 catch 块
					e.printStackTrace();
				}
				//进行初始化
			shopcart.setProduct(product);
			shopcart.setPrice(product.getSaleprice());
			shopcart.setCount(1);
			shopCartList.addElement(shopcart);
			session.setAttribute(Constants.SHOPCART_KEY,shopCartList);
 			PageForward="basket.jsp"; 
		}
		else{		
 			PageForward="wrong.jsp";  
		}
	   	resp.sendRedirect(PageForward);					
 	}		
}