updateorderbean.java

该系统具体分为2个部分：前台和后台。 1．前台主要用于用户进行浏览和搜索

package ynuBean;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class UpdateOrderBean 
{
	public UpdateOrderBean()
	{
		
	}
	
	public String AddOrder(String username,String pname,int orderqty)
	{
		String msg="";
		
		try
		{
			ConnectDataBase aConnect = new ConnectDataBase();
			Connection con = aConnect.getconnection();
			Statement sqlstatement = con.createStatement();
			//查找用户的余额
			GetDate aDate = new GetDate();		
			
			String query = "Select * from pesticide where Pname='"+pname+"'";
			ResultSet rs = sqlstatement.executeQuery(query);
			
			int curqty = 0;
			while(rs.next())
			{
				curqty = rs.getInt("qty");
			}
			
			curqty = curqty - orderqty;
			
			if(curqty>=0)
			{
				String insert = "insert into orderbyuser (username,pesticidename,orderdate,qty)"+
				" values('"+username+"','"+pname+"','"+aDate.getYearAndMonthAndDay()+"',"+orderqty+")";
				sqlstatement.executeUpdate(insert);

				String update="update pesticide set qty="+curqty+" where Pname='"+pname+"'";
				sqlstatement.executeUpdate(update);
				msg="成功订购,欢迎下次再次订购";
			}
			else
			{
				msg="库存不够,欢迎下次再次订购";
			}
			
			con.close();
		}
		catch (SQLException e) 
    	{
      		System.out.println(e.toString());
      		msg="订购失败,请重新点击订购";
    	}
    	catch (Exception e) 
    	{
    		System.out.println(e.toString());
    		msg="订购失败,请重新点击订购";
    	} 
    	
		return msg;
	}
	
	public String DeleteOrder(int ordernum,int qty,String pname)
	{
		String msg="";
		
		try
		{
			ConnectDataBase aConnect = new ConnectDataBase();
			Connection con = aConnect.getconnection();
			Statement sqlstatement = con.createStatement();
			//查找用户的余额
			String query = "Select * from pesticide where Pname='"+pname+"'";
			ResultSet rs = sqlstatement.executeQuery(query);
			
			int curqty = 0;
			while(rs.next())
			{
				curqty = rs.getInt("qty");
			}
			
			curqty = curqty + qty;
			
			String delete="delete from orderbyuser where ordernum="+ordernum+"";
			sqlstatement.executeUpdate(delete);
			
			String update="update pesticide set qty="+curqty+" where Pname='"+pname+"'";
			sqlstatement.executeUpdate(update);
			
			msg="成功取消订购,欢迎下次订购";			
			con.close();
		}
		catch (SQLException e) 
    	{
      		System.out.println(e.toString());
      		msg="取消失败,请继续";
    	}
    	catch (Exception e) 
    	{
    		System.out.println(e.toString());
    		msg="取消失败,请继续";
    	} 
    	
		return msg;
	}
}