1. 订单结算
2. 查看订单
3. 清空购物车

package com.ljq.servlet;

import java.io.IOException;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.ljq.biz.IOrderBiz;
import com.ljq.biz.IOrderItemBiz;
import com.ljq.biz.impl.OrderBizImpl;
import com.ljq.biz.impl.OrderItemBizImpl;
import com.ljq.pojo.Order;
import com.ljq.pojo.OrderItem;
import com.ljq.pojo.User;


@SuppressWarnings("all")
@WebServlet("/calc.do")
public class CalcServlet extends HttpServlet {

	private IOrderBiz orderBiz = new OrderBizImpl();
	private IOrderItemBiz orderItemBiz = new OrderItemBizImpl();

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		// 购物车在哪里?
		List car = (List) req.getSession().getAttribute("car");
		// 获得用户
		User user = (User) req.getSession().getAttribute("user");
		// 什么是结算? 将数据放到【订单】【订单项】
		if (car.isEmpty()) {
			// 返回购物车
			resp.sendRedirect("car.jsp");
			return;
		}
		// 计算总和
		int sum = 0;
		for (OrderItem item : car) {
			sum += item.getTotal();
		}
		// 优先结算订单
		Order order = new Order();
		order.setId(orderBiz.maxPK());
		order.setUserId(user.getId());
		order.setTotal(sum);
		// 将订单放到数据库
		int i = orderBiz.insert(order);
		if (i > 0) {
			// 如果订单插入成功了,则插入订单项
			for (OrderItem item : car) {
				// item没有id
				item.setId(orderItemBiz.maxPK());
				// 也没有订单编号
				item.setOrderId(order.getId());
				orderItemBiz.insert(item);
			}
			// 结算完毕
			car.clear();
			// 清空价格
			req.getSession().setAttribute("total", 0);
		}

		// 返回购物车
		resp.sendRedirect("car.jsp");
	}

}

orderservlet.java(处理显示)

package com.ljq.servlet;

import com.ljq.biz.IOrderBiz;
import com.ljq.biz.IOrderItemBiz;
import com.ljq.biz.impl.OrderBizImpl;
import com.ljq.biz.impl.OrderItemBizImpl;
import com.ljq.pojo.Order;
import com.ljq.pojo.OrderItem;
import com.ljq.pojo.User;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;


@SuppressWarnings("all")
@WebServlet("/order.do")
public class OrderServlet extends HttpServlet {

	private IOrderBiz orderBiz = new OrderBizImpl();

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		User user = (User) req.getSession().getAttribute("user");
		List list = orderBiz.list(user.getId());
		req.setAttribute("list", list);
		req.getRequestDispatcher("order.jsp").forward(req, resp);
	}

}

order.jsp

<%@ page language="java" contentType="text/html; charset=UTF-8"
	pageEncoding="UTF-8"%>













	

		
			
${user.account},welcome toorder
		
		
			继续购买
			返回购物车
		
		

			

				

					
订单编号
					
订单总价
					
订单操作
				

				

					
1
					
320.0
					
查看详情
				

			
		

	

效果图：

clearServlet

package com.ljq.servlet;

import com.ljq.pojo.OrderItem;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;


@SuppressWarnings("all")
@WebServlet("/clear.do")
public class ClearServlet extends HttpServlet {

	@Override
	protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		doPost(req, resp);
	}

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		List car = (List) req.getSession().getAttribute("car");
		car.clear();
		resp.sendRedirect("car.jsp");
	}

}

这次的MVC购物车小项目就全部搞定了！