listaction.java

mp3购物网站 使用struts框架

package com.yourcompany.struts.action;

import java.util.ArrayList;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.apache.struts.action.ActionForm;
import org.apache.struts.action.ActionForward;
import org.apache.struts.action.ActionMapping;
import org.apache.struts.actions.DispatchAction;

import com.yourcompany.dto.MP3;

public class ListAction extends DispatchAction {

	ArrayList<MP3> list = new ArrayList<MP3>();// 购物车al
	HttpSession session = null;
	ArrayList<MP3> alMP3 = null;

	public ActionForward show(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response) {

		session.setAttribute("list", list);
		return mapping.findForward("success");
	}

	public ActionForward add(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response) {

		 session= request.getSession();

		Object o = session.getAttribute("list");

		String id = request.getParameter("id");
		list = addGoods(id);
		session.setAttribute("list", list);

		return mapping.findForward("success");

	}

	public ActionForward modify(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response) {

		return null;
	}

	public ActionForward delete(ActionMapping mapping, ActionForm form,
			HttpServletRequest request, HttpServletResponse response) {

		return null;
	}

	// 从servletcontext中查询MP3
	public MP3 findMP3ByID(String id) {
		alMP3=(ArrayList<MP3>) servlet.getServletContext().getAttribute("alMP3");
		int size = alMP3.size();
		for (int i = 0; i < size; i++) {
			MP3 mp3 = alMP3.get(i);
			if (mp3.getId().equals(id))
				return mp3;
		}
		return null;
	}

	public ArrayList<MP3> addGoods(String id) {

		// 如果购物车没有物品，直接创建该物品的对象，然后添加到购物车中
		if (list.size() == 0) {

			MP3 mp3 = findMP3ByID(id);

			mp3.setQuantity("1");

			list.add(mp3);
		} else {
			int i = 0;
			boolean find = false;
			// 查找购物车中是否存在要添加的物品，如果存在直接修改购物车
			// 中物品的数量，如果不存在，则添加这个物品
			for (; i < list.size(); i++) {
				MP3 mp3 = (MP3) list.get(i);
				if (mp3.getId().equals(id)) {
					mp3.setQuantity(mp3.getQuantity() + 1);
					// 如果已经存在，修改数量

					list.set(i, mp3);

					find = true;
					break;
				}
			}
			if (!find) {
				MP3 mp3 = this.findMP3ByID(id);
				mp3.setQuantity("1");
				list.add(mp3);
			}
		}

		return list;

	}
}