showquoteservlet.java

JAVA 光盘操作说明 是解压包,直接解压就可以了

package examples;

import java.io.*;
import java.util.*;
import java.text.*;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.naming.*;

/**
 * 本servlet为客户提供浏览和修改购书车信息的功能
 */
public class ShowQuoteServlet extends HttpServlet {

	// 计价器 EJB 对象
	private Pricer pricer;

	/**
	 * 初始化servlet实例
	 */
	public void init(ServletConfig config) throws ServletException {

		super.init(config);

		try {
			/*
			 * 获取 JNDI 初始化参数
			 */
			String initCtxFactory = getInitParameter(Context.INITIAL_CONTEXT_FACTORY);
			String providerURL = getInitParameter(Context.PROVIDER_URL);

			
			Properties env = new Properties();
			env.put(Context.INITIAL_CONTEXT_FACTORY, initCtxFactory);
			env.put(Context.PROVIDER_URL, providerURL);

			/*
			 * 获取初始上下文
			 */
			Context ctx = new InitialContext(env);

			/*
			 * 查找计价器Home对象
			 */
			PricerHome pricerHome = (PricerHome) ctx.lookup("PricerHome");

			/*
			 * 创建一个计价器EJB对象
			 */
			pricer = pricerHome.create();
		} catch (Exception e) {
			log(e);
			throw new ServletException(e.toString());
		}
	}

	/**
	 * 回应客户端的HTTP请求
	 */
	public void service (HttpServletRequest request, HttpServletResponse response)
	throws ServletException, IOException {

		/*
		 * 获取客户端的HttpSession
		 * 为客户创建购书车
		 */
		HttpSession session = request.getSession(false);
		if (session == null) {
			/*
			 * 如果客户没有登录，把他重定向到登录页面
			 */
			response.sendRedirect(response.encodeRedirectURL("/BookStore/login"));
			return;
		}

		Object obj = session.getAttribute("cart");
		if (obj == null) {
			/*
			 * 如果客户没有登录，把他重定向到登录页面
			 */
			response.sendRedirect(response.encodeRedirectURL("/BookStore/login"));
			return;
		}
		Cart cart = (Cart) obj;                 

		/*
		 * 客户点击'提交订单'按钮
		 */
		if (request.getParameter("Order") != null) {
		    /*
		 	 * 把购书车转换成订单
		 	 */
			String orderId = cart.purchase();
            
	    	   	request.setAttribute("orderID", orderId );
			cart.clear();
			this.getServletContext().getRequestDispatcher("/receipt.jsp").forward(request, response);
			return;
		}
        
		Enumeration paramNames = request.getParameterNames();
		while (paramNames.hasMoreElements()) {
			String paramName = (String) paramNames.nextElement();
			String paramValue = request.getParameter(paramName);

			/*
			 * 客户点击'更新' 按钮
			 */
			if (paramName.equals("Update")) {
			}

			/*
			 * 客户清空表单
			 */
			else if (paramName.equals("Clear")) {
				cart.clear();
				this.getServletContext().getRequestDispatcher("/clearQuote.jsp").forward(request, response);
				return;
			}

			/*
			 * 如果参数是客户选购图书的数量
			 * 更新该项数值
			 */
			else {
                /*
                * 设置数值
                */
                try {
                    int quantity = Integer.parseInt(paramValue);
                    cart.modify(paramName, quantity);
				} catch (NumberFormatException e) {
                    throw new ServletException("Bad parameter to servlet: " + paramName + ", " + paramValue);
				} catch (Exception e) {
                    throw new ServletException(e.toString());
                }
            }
        }

		/*
		 * 重新计价
		 */
		try {
			pricer.price(cart);
		} catch (Exception e) {
			log(e);
			throw new ServletException(e.toString());
		}

		/*
		 * 否则显示当前的购书车状态
		 */
		Vector lineItems = cart.getAll();		
		if (lineItems.size() > 0) {
			
            request.setAttribute("lineItems", lineItems);
            request.setAttribute("subTotal", new Double(cart.getSubtotal()));
            request.setAttribute("taxes", new Double(cart.getTaxes()));
            request.setAttribute("total", new Double(cart.getTotalPrice()));
            //把请求转发给 showCart JSP.
            this.getServletContext().getRequestDispatcher("/showQuote.jsp").forward(request, response);
            return;
        }
		/*
		 * 如果客户未选购图书
		 * 显示购书车为空
		 */
		else {
			this.getServletContext().getRequestDispatcher("/emptyQuote.jsp").forward(request, response);
			return;
		}
	}
	
	private String format(double d) {
		NumberFormat nf = NumberFormat.getCurrencyInstance();
		return nf.format(d);
	}

	private void log(Exception e) {
		e.printStackTrace();
	}

	public String getServletInfo() {
		return "The ShowQuote servlet returns information about" +
		"the Books that the user is in the process of ordering.";
	}
}