public void createCoupon(String cou_name,String cou_file, int quantity){
		Connection conn = null;
		PreparedStatement pstmt = null;
		ResultSet rs = null;
		String sql = "";
		try{
			conn = getConnection();
			sql = "insert into coupon(cou_num,cou_name,cou_usage,cou_date.cou_file) values" +
					"(cou_num_seq.nextval,?,0,sysdate+180,?)";
			pstmt = conn.prepareStatement(sql);
			pstmt.setString(1, cou_name);
			pstmt.setString(2, cou_file);
			for(int i=0;i<quantity;i++){
				rs =pstmt.executeQuery(); 
			}			
		}catch(Exception ex){
			ex.printStackTrace();
		}finally{
			if(rs!=null)try{rs.close();}catch(SQLException ex){}
			if(pstmt!=null)try{pstmt.close();}catch(SQLException ex){}
			if(conn!=null)try{conn.close();}catch(SQLException ex){}
		}
	}