调用java.sql.PreparedStatement.cancel()方法.检查postgres JDBC驱动程序是否支持此方法.据我从最新的postgres JDBC驱动程序的源代码中看到的，它确实停止了查询.

Call java.sql.PreparedStatement.cancel() method. Check whether postgres JDBC driver supports this method. As far as I can see from the source code of the latest postgres JDBC driver it does stop the query.