public boolean updateBill(Bill b){
		connectionDB();
		boolean  isUpdate=false;
		String sql="update bill set goodsName=?,goodsNum=?,money=?,isPay=?,supplierName=?,goodsDescrible=?,billTime=? where billId=?";
		try {
			ps=conn.prepareStatement(sql);
			ps.setLong(8, b.getBillId());
			ps.setString(6, b.getGoodsDescrible());
			ps.setString(1, b.getGoodsName());
			ps.setString(4, b.getIsPay());
			ps.setString(5, b.getSupplierName());
			ps.setDate(7, b.getBillTime());
			ps.setInt(2,b.getGoodsNum());
			ps.setDouble(3, b.getMoney());
			int rows=ps.executeUpdate();
			isUpdate=rows>0?true:false;		
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally{
			closeDB();
		}
		return isUpdate;
	}