package servlet;

import java.io.IOException;

import java.io.PrintWriter;

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import dao.ItemsDAO;

import entity.Cart;

import entity.Items;

public class CartServlet extends HttpServlet {

private String action ; //表示購物車的動作 ,add,show,delete

//商品業(yè)務邏輯類的對象

private ItemsDAO idao = new ItemsDAO();

/**

* Constructor of the object.

*/

public CartServlet() {

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>

*

* This method is called when a form has its tag value method equals to get.

*?

* @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 {

? ? ? ? doPost(request,response);

}

/**

* 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=utf-8");

PrintWriter out = response.getWriter();

if(request.getParameter("action")!=null)

{

this.action = request.getParameter("action");

if(action.equals("add")) //如果是添加商品進購物車

{

if(addToCart(request,response))

{

request.getRequestDispatcher("/success.jsp").forward(request, response);

}

else

{

request.getRequestDispatcher("/failure.jsp").forward(request, response);

}

}

if(action.equals("show"))//如果是顯示購物車

{

request.getRequestDispatcher("/cart.jsp").forward(request, response);

}

if(action.equals("delete")) //如果是執(zhí)行刪除購物車中的商品

{

if(deleteFromCart(request,response))

{

request.getRequestDispatcher("/cart.jsp").forward(request, response);

}

else

{

request.getRequestDispatcher("/cart.jsp").forward(request, response);

}

}

}

}

//添加商品進購物車的方法

private boolean addToCart(HttpServletRequest request, HttpServletResponse response)

{

String id = request.getParameter("id");

String number = request.getParameter("num");

Items item = idao.getItemsById(Integer.parseInt(id));

//是否是第一次給購物車添加商品,需要給session中創(chuàng)建一個新的購物車對象

if(request.getSession().getAttribute("cart")==null)

{

Cart cart = new Cart();

request.getSession().setAttribute("cart",cart);

}

Cart cart = (Cart)request.getSession().getAttribute("cart");

if(cart.addGoodsInCart(item, Integer.parseInt(number)))

{

return true;

}

else

{

return false;

}

}

//從購物車中刪除商品

private boolean deleteFromCart(HttpServletRequest request, HttpServletResponse response)

{

String id = request.getParameter("id");

Cart cart = (Cart)request.getSession().getAttribute("cart");

? ?Items item = idao.getItemsById(Integer.parseInt(id));

? ?if(cart.removeGoodsFromCart(item))

? ?{

? ? return true;

? ?}

? ?else

? ?{

? ? return false;

? ?}

}

/**

* Initialization of the servlet. <br>

*

* @throws ServletException if an error occurs

*/

public void init() throws ServletException {

// Put your code here

}

}

private boolean addToCart(HttpServletRequest request, HttpServletResponse response)

為什么這個方法的參數(shù)是HttpServletRequest request, HttpServletResponse response，不太懂，而且為什么返回值要弄成布爾類型？