jsp 购物车源码 servlet

package com.servlet; import java.io.IOException; import java.io.PrintWriter; import java.util.Collection; import java.util.HashMap; import java.util.Map; 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 com.dao.BookDao; import com.entity.Book; import com.entity.CratItem; public class AddCartServlet extends HttpServlet { /** * Constructor of the object. */ public AddCartServlet() { 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 { response.setContentType("text/html"); request.setCharacterEncoding("gbk"); response.setCharacterEncoding("gbk"); PrintWriter out = response.getWriter(); String[] id=request.getParameterValues("chk"); HttpSession session=request.getSession(); Map carts=(Map) session.getAttribute("carts"); if(carts==null){ carts=new HashMap(); } BookDao bookDao=new BookDao(); if(id!=null){ for (int i = 0; i < id.length; i++) { Book book=bookDao.getById(id[i]); CratItem cratItem=(CratItem) carts.get(id[i]); if (cratItem==null) { cratItem=new CratItem(book,1); carts.put(id[i], cratItem); }else{ cratItem.setNum(cratItem.getNum()+1); carts.put(id[i], cratItem); } } } session.setAttribute("carts", carts); Collection collection=carts.values(); request.setAttribute("cartsList", collection); request.getRequestDispatcher("ViewCart.jsp").forward(request, response); out.flush(); out.close(); } /** * 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 { doGet(request, response); } /** * Initialization of the servlet. <br> * * @throws ServletException if an error occure */ public void init() throws ServletException { // Put your code here } }