clearcartservlet.java

该项目为网上书店

package org.myrose.servlet;

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

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 class ClearCartServlet extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public ClearCartServlet() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 * 
	 * 此方法用来清除购物车，如果 id 不为空，
	 * 表示清除购物车中某个商品，否则全部清空
	 * 
	 * @param request
	 *            the request send by the client to the server
	 * @param response
	 *            the response send by the server to the client
	 * @throws ServletException
	 *             if an error occurred
	 * @throws IOException
	 *             if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html;charset=GBK");
		request.setCharacterEncoding("GBK");

		String id = request.getParameter("id");
		HttpSession session = request.getSession();

		if (id != null && !id.equals("")) {
			
			Vector cart = (Vector) session.getAttribute("cart");
			
			try {
				cart.removeElementAt(Integer.parseInt(id));
				if (cart.size() == 0) {
					response.sendRedirect("cart_null.jsp");
				} else {
					session.setAttribute("cart", cart);
					response.sendRedirect("cart_see.jsp");
				}
			} catch (Exception e) {
				e.printStackTrace();
			}
		}else{
		session.removeAttribute("cart");
		response.sendRedirect("cart_null.jsp");
		}
	}

	/**
	 * The doPost method of the servlet. <br>
	 * 
	 * This method is called when a form has its tag value method equals to
	 * post.
	 * 
	 * @param request
	 *            the request send by the client to the server
	 * @param response
	 *            the response send by the server to the client
	 * @throws ServletException
	 *             if an error occurred
	 * @throws IOException
	 *             if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		response.setContentType("text/html;charset=GBK");
		request.setCharacterEncoding("GBK");
		this.doGet(request, response);
	}

	/**
	 * Initialization of the servlet. <br>
	 * 
	 * @throws ServletException
	 *             if an error occure
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}