cartservlet.java

来自「精通NetBeans光盘源代码,很好很好的资料」· Java 代码 · 共 100 行

package shop.cart;
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import javax.naming.*;
import javax.rmi.*;
import javax.ejb.*;

public class CartServlet extends HttpServlet {
    
    private ShoppingCartRemoteHome home;
    private ShoppingCartRemote shoppingCart;
    
    public void init() throws ServletException {
        home = lookupHome();        
        super.init();
    }    
    
    //Process the HTTP Post request
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {        
        //能处理中文参数乱码问题
        request.setCharacterEncoding("ISO-8859-1");        
        //得到参数a的数值
        String action = (String)request.getParameter("a");                   
        HttpSession session = request.getSession(true);        
        //如果用户不是第一次访问，通过Session让用户使用已有的实例，否则建一个新的        
        if(session.getAttribute("cart") == null){            
            try{
                shoppingCart = home.create();
                session.setAttribute("cart",shoppingCart);                
            }catch(Exception ce){                
                ce.printStackTrace();
            }
        }
        else{
            shoppingCart = (ShoppingCartRemote)session.getAttribute("cart");
        }
        //处理各种请求
        if(action.equals("get")){//处理请求购物车的请求
            //跳转页面
            forward(request,response,"/cart.jsp");
        }else if (action.equals("remove")) {//处理删除购物车中商品的请求
            String id = (String) request.getParameter("id");
            shoppingCart.removeFromCart(id);
            forward(request,response,"/cart.jsp");
            
        }else if(action.equals("add")){//处理往购物车中加商品的请求
            String id = (String) request.getParameter("id");
            String title = (String) request.getParameter("title");
            title=new String(title.getBytes("ISO-8859-1"),"GBK");
            double price = Double.parseDouble(request.getParameter("price"));
            shoppingCart.addToCart(id,title,price,1);
            forward(request,response,"/video.jsp");
        }      
    }
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }
    
    /** Handles the HTTP <code>POST</code> method.
     * @param request servlet request
     * @param response servlet response
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
    throws ServletException, IOException {
        processRequest(request, response);
    }
    
    /** Returns a short description of the servlet.
     */
    public String getServletInfo() {
        return "Short description";
    }
    // Lookup the beans home using JNDI
    private ShoppingCartRemoteHome lookupHome() {
        ShoppingCartRemoteHome myHome = null;
        try {            
            Hashtable ht = new Hashtable();
            ht.put(Context.INITIAL_CONTEXT_FACTORY,"org.jnp.interfaces.NamingContextFactory");
            ht.put(Context.PROVIDER_URL, "localhost:1099");
            Context ctx = new InitialContext(ht);
            Object home = ctx.lookup("ShoppingCartJndi");
            myHome = (ShoppingCartRemoteHome) PortableRemoteObject.narrow(home, ShoppingCartRemoteHome.class);
        } catch (Exception e) {
            System.out.println("The client was unable to lookup the EJBHome.");
            e.printStackTrace();
        }
        return myHome;
    }
    protected void forward(HttpServletRequest request,HttpServletResponse response,String url)    throws ServletException,IOException {
        RequestDispatcher dispatcher = request.getRequestDispatcher(url);
        dispatcher.forward(request, response);
        
    }
}