conn,stmt,rset 的关闭(规范)
Connection conn = null; Statement stmt = null; ResultSet rset = null; try { conn = dataSource.getConnection(); stmt = conn.createStatement(); rset = stmt.executeQuery("select 1 from dual"); } catch (SQLException e) { e.printStackTrace(); } finally { try { if (rset != null) rset.close(); } catch(Exception e) { } try { if (stmt != null) stmt.close(); } catch(Exception e) { } try { if (conn != null) conn.close(); } catch(Exception e) { } }