day03 --serlet的抽取 购物车显示 删除单个商品 清空购物车

servlet的抽取

public class BaseServlet extends HttpServlet {

	@Override
	protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		
		req.setCharacterEncoding("utf-8");
		
		try {
			//1.获得请求的method名称
			String methodName = req.getParameter("method");
			//2.获得当前被访问的字节码对象
			Class<? extends BaseServlet> clazz = this.getClass();
			//3.获得当前字节码对象中指定的方法
			Method method = clazz.getMethod(methodName, HttpServletRequest.class,HttpServletResponse.class);
			//4.执行相应功能方法
			method.invoke(this, req,resp);
			
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

}

 

购物车相关

Cart

public class Cart {

	//该购物车中存储的n个购物项
	private Map<String,CartItem> cartItems = new HashMap<String,CartItem>();
	//商品总计
	private double total;
	public Map<String, CartItem> getCartItems() {
		return cartItems;
	}
	public void setCartItems(Map<String, CartItem> cartItems) {
		this.cartItems = cartItems;
	}
	public double getTotal() {
		return total;
	}
	public void setTotal(double total) {
		this.total = total;
	}
	
}

CartItem

public class CartItem {

	private Product product;
	private int buyNum;
	private double subtotal;
	public Product getProduct() {
		return product;
	}
	public void setProduct(Product product) {
		this.product = product;
	}
	public int getBuyNum() {
		return buyNum;
	}
	public void setBuyNum(int buyNum) {
		this.buyNum = buyNum;
	}
	public double getSubtotal() {
		return subtotal;
	}
	public void setSubtotal(double subtotal) {
		this.subtotal = subtotal;
	}	
}

Product

public class Product {

	private String pid;
	private String pname;
	private double market_price;
	private double shop_price;
	private String pimage;
	private Date pdate;
	private int is_hot;
	private String pdesc;
	private int pflag;
	//cid外键，直接引用对象
	private Category category;
	
	public String getPid() {
		return pid;
	}
	public void setPid(String pid) {
		this.pid = pid;
	}
	public String getPname() {
		return pname;
	}
	public void setPname(String pname) {
		this.pname = pname;
	}
	public double getMarket_price() {
		return market_price;
	}
	public void setMarket_price(double market_price) {
		this.market_price = market_price;
	}
	public double getShop_price() {
		return shop_price;
	}
	public void setShop_price(double shop_price) {
		this.shop_price = shop_price;
	}
	public String getPimage() {
		return pimage;
	}
	public void setPimage(String pimage) {
		this.pimage = pimage;
	}
	public Date getPdate() {
		return pdate;
	}
	public void setPdate(Date pdate) {
		this.pdate = pdate;
	}
	public int getIs_hot() {
		return is_hot;
	}
	public void setIs_hot(int is_hot) {
		this.is_hot = is_hot;
	}
	public String getPdesc() {
		return pdesc;
	}
	public void setPdesc(String pdesc) {
		this.pdesc = pdesc;
	}
	public int getPflag() {
		return pflag;
	}
	public void setPflag(int pflag) {
		this.pflag = pflag;
	}
	public Category getCategory() {
		return category;
	}
	public void setCategory(Category category) {
		this.category = category;
	}
	@Override
	public String toString() {
		return "Product [pid=" + pid + ", pname=" + pname + ", market_price=" + market_price + ", shop_price="
				+ shop_price + ", pimage=" + pimage + ", pdate=" + pdate + ", is_hot=" + is_hot + ", pdesc=" + pdesc
				+ ", pflag=" + pflag + ", category=" + category + "]";
	}
	
}

 

ProductServlet

public class ProductServlet extends HttpServlet {

	private static final long serialVersionUID = 1L;

	protected void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("UTF-8");
		response.setCharacterEncoding("UTF-8");
		response.setContentType("text/html; charset=UTF-8");
		
		//获得请求的方法
		String methodName = request.getParameter("method");
		if("productList".equals(methodName)){
			productList(request,response);
		}else if("categoryList".equals(methodName)){
			categoryList(request,response);
		}else if("index".equals(methodName)){
			index(request,response);
		}else if("productInfo".equals(methodName)){
			productInfo(request,response);
		}else if("addProductToCart".equals(methodName)){
			addProductToCart(request,response);
		}else if("delProFromCart".equals(methodName)){
			delProFromCart(request,response);
		}
		
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		doGet(request, response);
	} 

	
	//添加商品到购物车
	public void addProductToCart(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
		
		HttpSession session = request.getSession();
		
		ProductService service = new ProductService();
		
		//获得要放到购物车的pid
		String pid = request.getParameter("pid");
		//获得该商品的购买输量
		int buyNum = Integer.parseInt(request.getParameter("buyNum"));
		
		//获得product对象
		Product product = service.findProductByPid(pid);
		//计算小计
		double subtotal = product.getShop_price()*buyNum;
		//封装成CartItem
		CartItem item = new CartItem();
		item.setBuyNum(buyNum);
		item.setProduct(product);
		item.setSubtotal(subtotal);
		
		//获得购物车--判断是否在session中已经存在购物车
		Cart cart = (Cart) session.getAttribute("cart");
		if(cart == null){
			//第一次访问，没有cart，新建
			cart = new Cart();
		}
		
		//将购物项放到购物车中--key是pid
		//先判断购物车总是否已经包含此购物项了-- 判断key是否已经存在
		//如果购物车中已经存在该商品--将现在购买的数量与原有的数量相加
		Map<String, CartItem> cartItems = cart.getCartItems();
		
		if(cartItems.containsKey(pid)){
			//取出原有的商品数量
			CartItem cartItem = cartItems.get(pid);
			int oldBuyNum = cartItem.getBuyNum();
			oldBuyNum+=buyNum;
			cartItem.setBuyNum(oldBuyNum);
			
			cart.setCartItems(cartItems);
			//修改小计
			//小计=数量*单价
			cartItem.setSubtotal(oldBuyNum*product.getShop_price());
		
		}else{
			//如果购物车中没有该商品
			cartItems.put(pid, item);
		}
		
		//计算总计
		//原先的总价+这次的小计
		double total = cart.getTotal()+subtotal;
		cart.setTotal(total);
		 
		//将车再次访问session
		session.setAttribute("cart", cart);
			
		//直接跳转到购物车页面
		//请求转发和重定向的区别在此，如果用请求转发，地址不发生 变化，再次刷新，重新访问一次servlet,数量发生变化。实际上不应该变化，所以用重定向
		//request.getRequestDispatcher("cart.jsp").forward(request, response);
		response.sendRedirect(request.getContextPath()+"/cart.jsp");
	}
	
	//删除一个购物项
	public void delProFromCart(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
		
		String pid = request.getParameter("pid");
		//删除session中的购物车中的购物项集合中的item
		HttpSession session = request.getSession();
		Cart cart = (Cart) session.getAttribute("cart");
		if(cart != null){
			Map<String, CartItem> cartItems = cart.getCartItems();
			//需要修改总价
			cart.setTotal(cart.getTotal()-cartItems.get(pid).getSubtotal());
			cartItems.remove(pid);
			
		}
		
		session.setAttribute("cart", cart);
		
		//跳转回购物车页面
		response.sendRedirect(request.getContextPath()+"/cart.jsp");
	}
	
	//清空购物车
	public void clearCart(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException{
		HttpSession session = request.getSession();
		session.removeAttribute("cart");
		
		response.sendRedirect(request.getContextPath()+"/cart.jsp");
		
	}

}

cart.jsp

		<!-- 判断购物车中是否还有商品 -->
		<c:if test="${!empty cart.cartItems }">
			<div class="container">
				<div class="row">
					<div style="margin:0 auto; margin-top:10px;width:950px;">
						<strong style="font-size:16px;margin:5px 0;">订单详情</strong>
						<table class="table table-bordered">
							<tbody>
								<tr class="warning">
									<th>图片</th>
									<th>商品</th>
									<th>价格</th>
									<th>数量</th>
									<th>小计</th>
									<th>操作</th>
								</tr>
								
								<!-- map的遍历 -->
								<c:forEach items="${cart.cartItems }" var="entry" >							
									<tr class="active">
										<td width="60" width="40%">
											<input type="hidden" name="id" value="22">
											<img src="${pageContext.request.contextPath }/${entry.value.product.pimage}" width="70" height="60">
										</td>
										<td width="30%">
											<a target="_blank">${entry.value.product.pname }</a>
										</td>
										<td width="20%">
											${entry.value.product.shop_price } 
										</td>
										<td width="10%">
											${entry.value.buyNum }
										</td>
										<td width="15%">
											<span class="subtotal">${entry.value.subtotal}</span>
										</td>
										<td>
											<a href="javascript:void(0);" onclick="delProFromCart('${entry.value.product.pid}')" class="delete">删除</a>
										</td>
									</tr>
								</c:forEach>
							</tbody>
						</table>
					</div>
				</div>
	
				<div style="margin-right:130px;">
					<div style="text-align:right;">
						<em style="color:#ff6600;">
					登录后确认是否享有优惠  
				</em> 赠送积分: <em style="color:#ff6600;">596</em>  商品金额: <strong style="color:#ff6600;">${cart.total }元 </strong>
					</div>
					<div style="text-align:right;margin-top:10px;margin-bottom:10px;">
						<a href="javascript:void(0)" onlick="clearCart();" id="clear" class="clear">清空购物车</a>
						<a href="order_info.htm">
							<input type="submit" width="100" value="提交订单" name="submit" border="0" style="background: url('./images/register.gif') no-repeat scroll 0 0 rgba(0, 0, 0, 0);
							height:35px;width:100px;color:white;">
						</a>
					</div>
				</div>
			</div> 
		</c:if>
		<c:if test="${empty cart.cartItems }">
			<div>
				<img alt="" src="${pageContext.request.contextPath}/images/cart-empty.png">
				<a href="${pageContext.request.contextPath }/index">返回首页</a>
			</div>
		</c:if>