public void insertRecord(TradeRecord tr) {
		// ݿ
		String sql = "insert into traderecord(userId,bookId,tradeNum,sum) values(?,?,?,?)";
		
		try {
			// ݿ
			conn = manager.getConnection();
			// Ԥ
			pstmt = conn.prepareStatement(sql);
			// νԲݿ
			pstmt.setString(1, String.valueOf(tr.getUserId()));
			pstmt.setString(2, String.valueOf(tr.getBookId()));
			pstmt.setString(3, String.valueOf(tr.getTradeNum()));
			pstmt.setString(4, String.valueOf(tr.getSum()));
			pstmt.executeUpdate();
		} catch (SQLException e) {
			e.printStackTrace();

		} catch (Exception e) {

			e.printStackTrace();

		} finally {
			// رݿ
			manager.closeAll(rs,stmt,conn);
		}
	}