我有一个在Glassfish服务器上运行的后端部署，我的应用程序的前端在需要一些数据时会发送REST请求。另外，后端连接到Mongo数据库：
前端<---- rest ----> BACKEND <----> DB。
我的后端通过glassfish 5部署在Ubuntu虚拟机上，前端在Apache Web服务器上运行。
使用一段时间后，我们可以说5分钟后，尤其是当多个用户正在使用该应用程序时，glassfish服务器在尝试访问数据库时大部分时间都崩溃，错误为：java.net.SocketException: Too many open files。
当然，我已经在Google上搜索了此问题，并且有许多建议只是说要增加打开文件的数量，而现在1024。
现在我的问题是，这些打开的文件是什么，即使我增加了它们，过一段时间也不会达到限制。是增加唯一的解决方案，还是我的编码中可能有错误？预先感谢。
编辑： 这是我的ubuntu机器的netstat输出的一个片段：
tcp 0 0 localhost:27017 localhost:44856 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44980 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44794 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:45132 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44764 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44814 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44756 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44374 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44926 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:45040 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:45276 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44858 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:45052 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:45310 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44806 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44840 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:45046 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:45222 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:45160 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44990 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44914 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:45274 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44998 ESTABLISHED -
tcp 0 0 localhost:27017 localhost:44788 ESTABLISHED -
tcp6 0 0 localhost:45176 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:45136 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:45058 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:44926 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:44968 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:45190 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:45050 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:44886 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:45308 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:44978 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:45086 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:45198 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:44922 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:44938 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:45020 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:44896 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:44830 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:44960 localhost:27017 ESTABLISHED 5204/java
tcp6 0 0 localhost:44776 localhost:27017 ESTABLISHED 5204/java
如您所见，有一种方法可以与mongo数据库localhost：27017建立连接。