code: public static void rollbackTransaction() {
          Connection connection = tl_conn.get();
          if (connection == null) {
              throw new RuntimeException("You do not start a Transaction so you can not rollback a transaction!");
          }
          try {
              connection.rollback();
              connection.close();
              tl_conn.remove();
              tl_sp.remove();
          } catch (SQLException e) {
              throw new RuntimeException(e);
          }
      }
docs: 回滚事务并关闭该连接，该事务连接是线程安全的。