jsp学习笔记（28）
ReckoningServlet代码如下：package servlet.user;import java.io.IOException;import java.sql.Connection;import java.sql.ResultSet;import java.sql.Statement;import java.util.ArrayList;import java.util.Iterator;import javax.servlet.RequestDispatcher;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;import dao.DBConnection;import bean.Cart;import bean.CartItem;public class ReckoningServlet extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {HttpSession session = request.getSession();Cart cart = (Cart) session.getAttribute("cart");if (cart == null || cart.getCart().size()==0) {request.setAttribute("null", "1");} else {ArrayList login = (ArrayList) session.getAttribute("login");String userId = (String) login.get(0);DBOperation dbo=new DBOperation();ArrayList<CartItem> al = cart.getCart();Iterator<CartItem> it = al.iterator();String bookId = "";int bookQuantity = 0;String SQL1 = "";String SQL2 = "";String SQL3 = "";String SQL4 = "";while(it.hasNext()){CartItem cartItem = it.next();bookId = cartItem.getId();bookQuantity = cartItem.getQuantity();SQL1 = "update books set storage=storage-"+bookQuantity+" where id = "+bookId+"";dbo.insertDeleteUpdate(SQL1);SQL2 = "insert into orders(userid,bookid,booksum,times) values ("+userId+","+bookId+","+bookQuantity+",Getdate())";dbo.insertDeleteUpdate(SQL2);SQL3 = "select * from rank where bookid = "+bookId+"";if(dbo.queryReturnboolean(SQL3)){SQL4 = "update rank set quantity=quantity+"+bookQuantity+" where bookid="+bookId+"";dbo.insertDeleteUpdate(SQL4);}else{SQL4 = "insert into rank(bookid,quantity) values("+bookId+","+bookQuantity+")";dbo.insertDeleteUpdate(SQL4);}}request.setAttribute("ok", "1");session.removeAttribute("cart");}RequestDispatcher rd = request.getRequestDispatcher("/user/cart.jsp");rd.forward(request, response);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}}