mycart.java

用MVC实现JSP购物车案例说明详细设计方案

package com.shop.model;
import java.sql.*;
import java.util.*;
public class MyCart {
	HashMap hm=new HashMap();
	private Connection conn=null;
	private PreparedStatement pstmt=null;
	private ResultSet rs=null;
	
	/**
	 * @author 让痛苦痛苦
	 * @param 返回指定书ID的数量 
	 */
	public String getNum(String id){
		return hm.get(id).toString();
	}
	
	
	//添加书
	/**
	 * @author 让痛苦痛苦
	 * @param addBook 添加书
	 */
	public void addBook(String bookid,String nums)
	{
		hm.put(bookid, nums);
	}
	/**
	 * @author 让痛苦痛苦
	 * @param delBook 删除书
	 */
	public void delBook(String bookid)
	{
		hm.remove(bookid);
	}
	/**
	 * @author 让痛苦痛苦 
	 * @param update 修改书
	 */
	public void updateBook(String bookid,String newNums)
	{
		hm.put(bookid, newNums);
	}
	/**
	 * @author 让痛苦痛苦
	 *@param clearMayCart 清空我的购物车内存
	 */
	public void clearMyCart()
	{
		hm.clear();
	}
	
	/**
	 * @author 让痛苦痛苦
	 * @param getTotalPrice 返回总价
	 * 
	 */
	public float getTotalPrice()
	{
		float totalPrice =0;
		try {
			Iterator it=hm.keySet().iterator();
			String allBookId="";
			while(it.hasNext())
			{
				String bookId =(String)it.next();
				//循环取出书号，并将它加上“,”
				allBookId+=bookId+",";
			}
			//将allBookId最后一个逗号去掉
			allBookId=allBookId.substring(0,allBookId.length()-1);
			
			String sql="select * from goods where s_id in ("+allBookId+")";
			
			conn=new Conn().getConn();
			pstmt=conn.prepareStatement(sql);
			rs=pstmt.executeQuery();
			while(rs.next())
			{
				totalPrice=totalPrice+rs.getFloat(3)*1;
			}
		} catch (Exception e) {
			e.printStackTrace();
			// TODO: handle exception
		}
		finally 
		{
			try {
				rs.close();
				pstmt.close();
				conn.close();
			} catch (Exception e) {
				e.printStackTrace();
				// TODO: handle exception
			}
		}
		return totalPrice;
	}
	/**
	 * @author 让痛苦痛苦
	 * @return showMyCart 显示所有的书
	 */
	public ArrayList showMyCart()
	{
		ArrayList al=new ArrayList();
		try {
			Iterator it=hm.keySet().iterator();
			String allBookId="";
			while(it.hasNext())
			{
				String bookId=(String)it.next();
				allBookId+=bookId+",";
			}
			
			allBookId=allBookId.substring(0,allBookId.length()-1);
			
			String sql="select * from goods where s_id in("+allBookId+")";
			
			conn=new Conn().getConn();
			pstmt=conn.prepareStatement(sql);
			rs=pstmt.executeQuery();
			
			while(rs.next())
			{
				GoodsBean gb=new GoodsBean();
				gb.setS_id(rs.getInt(1));
				gb.setS_name(rs.getString(2));
				gb.setS_price(rs.getFloat(3));
				gb.setS_more(rs.getInt(4));
				gb.setS_house(rs.getString(5));
				al.add(gb);
			}
			
		} catch (Exception e) {
			e.printStackTrace();
			// TODO: handle exception
		}
		finally 
		{
			try {
				rs.close();
				pstmt.close();
				conn.close();
			} catch (Exception e) {
				e.printStackTrace();
				// TODO: handle exception
			}
		}
		return al;
	}

}