shoppingcartactions.java

采用Struts框架做的网上啤酒买卖系统

package com.cavaness.beer4all.order;

import java.io.IOException;
import java.text.Format;
import java.text.NumberFormat;
import java.util.*;
import javax.servlet.ServletException;
import javax.servlet.http.*;
import org.apache.struts.action.*;
import org.apache.struts.actions.DispatchAction;
import com.cavaness.beer4all.service.Beer4AllService;
import com.cavaness.beer4all.common.view.UserView;
import com.cavaness.beer4all.catalog.view.ItemView;
import com.cavaness.beer4all.framework.UserContainer;
import com.cavaness.beer4all.util.Constants;
import com.cavaness.beer4all.framework.ShoppingCartItem;
import com.cavaness.beer4all.framework.ShoppingCart;
import com.cavaness.beer4all.framework.Beer4AllBaseDispatchAction;

//这个类执行所有购物车的功能，它通过Beer4AllBaseDispatchAction基类继承DispatchAction
public class ShoppingCartActions extends Beer4AllBaseDispatchAction {
  //创建一个用户信息库
  public ActionForward view(ActionMapping mapping,
                            ActionForm form,
                            HttpServletRequest request,
                            HttpServletResponse response)
    throws Exception {

    //创建一个用户信息
    UserContainer userContainer = getUserContainer(request);
    //返回一个成功状态的映射
    return mapping.findForward(Constants.SUCCESS_KEY);
  }
  //这个方法依据请求信息更新购物车中的商品信息
  public ActionForward update(ActionMapping mapping,
                              ActionForm form,
                              HttpServletRequest request,
                              HttpServletResponse response)
    throws Exception {
     //更新商品列表
     updateItems(request);
     //更新商品数量
     updateQuantities(request);
     //返回一个成功状态的映射
     return mapping.findForward(Constants.SUCCESS_KEY);
  }

  //这个方法向购物车中添加一个商品类别和数量
  public ActionForward addItem(ActionMapping mapping,
                               ActionForm form,
                               HttpServletRequest request,
                               HttpServletResponse response)
    throws Exception {
    //获取用户信息库
    UserContainer userContainer = getUserContainer(request);

    //获取商品ID
    String itemId = request.getParameter( Constants.ID_KEY );
    //获取商品数量
    String qtyParameter = request.getParameter( Constants.QTY_KEY );
    //获取商品包装单位
    String uomParameter = request.getParameter( Constants.UOM_KEY );
    //默认商品数量为1
    int quantity = 1;
    if(qtyParameter != null) {
      //获取用户的Locale信息
      Locale userLocale = userContainer.getLocale();
      //将输入格式定为用户所支持的格式
      Format nbrFormat = NumberFormat.getNumberInstance(userLocale);
      try {
        //获取用户发送的商品数量信息
        Object obj = nbrFormat.parseObject(qtyParameter);
        quantity = ((Number)obj).intValue();
      }
      catch(Exception ex) {
        ex.printStackTrace();
      }
    }

    //得到一个指定服务
    Beer4AllService serviceImpl = this.getBeer4AllService();
    //依据商品ID获取商品信息
    ItemView ItemView = serviceImpl.getItemById( itemId );

    //添加一个一个商品类别和数量的信息到购物车
    userContainer.getCart().addItem(new ShoppingCartItem(ItemView, quantity));
    //返回一个成功状态的映射
    return mapping.findForward(Constants.SUCCESS_KEY);
  }

  //更新购物车中的商品列表信息,将不需要的商品删除
  private void updateItems(HttpServletRequest request) {
    //获取需要被删除的商品ID
    String[] deleteIds = request.getParameterValues("deleteCartItem");

    //建立需要被删除的商品ID列表
    if(deleteIds != null && deleteIds.length > 0) {
      //获取需要被删除的商品类数量
      int size = deleteIds.length;
      //创建一个商品ID列表
      List itemIds = new ArrayList();
      for(int i = 0;i < size;i++) {
        itemIds.add(deleteIds[i]);
      }
      //获取用户信息库
      UserContainer userContainer = getUserContainer(request);
      //从用户的购物车中删除需要被删除的商品
      userContainer.getCart().removeItems(itemIds);
    }
  }

  //更新购物车中的商品的购买数量
  private void updateQuantities(HttpServletRequest request) {
    //将客户请求中的参数名转化为一个枚举
    Enumeration enum = request.getParameterNames();
    //遍历枚举中的每一个参数名
    while(enum.hasMoreElements()) {
      String paramName = (String)enum.nextElement();
      //当参数名由"qty_"为开头时
      if(paramName.startsWith("qty_")) {
        //截取该参数中第4到最后一位的字符串，即需要更新的商品ID
        String id = paramName.substring(4, paramName.length());
        //获取该参数
        String qtyStr = request.getParameter(paramName);
        //如果该商品ID和数量都存在
        if(id != null && qtyStr != null) {
          //获取用户的购物车
          ShoppingCart cart = getUserContainer(request).getCart();
          //输出字符串
          System.out.println( "id = " + id + " qty = " + qtyStr );
          //更新购物车中商品的数量为用户的请求值
          cart.updateQuantity(id, Integer.parseInt(qtyStr));
        }
      }
    }
  }
  //校验用户是否有购买商品的权限
  public ActionForward checkout(ActionMapping mapping,
                               ActionForm form,
                               HttpServletRequest request,
                               HttpServletResponse response)
    throws Exception {
      // Make sure the user is logged in first


      // Just forward to the checkout page
      //返回一个成功状态的映射
      return mapping.findForward( Constants.SUCCESS_KEY );
    }
  //确认操作
  public ActionForward finalizeOrder(ActionMapping mapping,
                               ActionForm form,
                               HttpServletRequest request,
                               HttpServletResponse response)
    throws Exception {


      // Just forward to the order confirmation page
      return mapping.findForward( Constants.CONFIRM_ORDER_KEY );
    }


}