Spring Data MongoDB无法关闭MongoDB连接

我在我的Web应用程序中使用带有spring-webmvc框架的spring-data-mongodb（1.7.0.RELEASE）。我正在使用使用mongoRepository的基本CRUD函数，但是我没有在代码中关闭mongo连接，因为我认为spring-data-mongodb会自行关闭它，但是它一直在打开新连接而不关闭它们。这些太多的连接都使我的应用程序崩溃，我不得不一次又一次（一天两次）重新启动tomcat来克服此问题。

注意：Spring Application和mongod在同一服务器上。这是崩溃后的日志-

    2015-07-17T01:31:20.068-0400 I NETWORK  [conn3645] end connection 127.0.0.1:55302 (2583 connections now open)
    2015-07-17T01:31:20.071-0400 I NETWORK  [conn1713] end connection 127.0.0.1:48174 (2352 connections now open)
    2015-07-17T01:31:20.072-0400 I NETWORK  [conn2250] end connection 127.0.0.1:51017 (2325 connections now open)
    2015-07-17T01:31:20.072-0400 I NETWORK  [conn2149] end connection 127.0.0.1:50670 (2320 connections now open)

这是重启tomcat后的日志

2015-07-17T01:31:29.994-0400 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:53599 #3984 (1 connection now open)
2015-07-17T01:31:33.263-0400 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:53740 #3985 (2 connections now open)
2015-07-17T01:31:33.580-0400 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:53750 #3986 (3 connections now open)
2015-07-17T02:10:06.477-0400 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:50086 #3987 (4 connections now open)
2015-07-17T02:10:06.590-0400 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:50090 #3988 (5 connections now open)
2015-07-17T02:10:11.682-0400 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:50242 #3989 (6 connections now open)
2015-07-17T02:10:11.780-0400 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:50244 #3990 (7 connections now open)
2015-07-17T02:10:12.545-0400 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:50255 #3991 (8 connections now open)
2015-07-17T02:10:12.605-0400 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:50258 #3992 (9 connections now open)
2015-07-17T02:10:13.413-0400 I NETWORK  [initandlisten] connection accepted from 127.0.0.1:50299 #3993 (10 connections now open)

每当我向应用程序发送请求时，它就会增加。

这是崩溃后的tomcat日志-

Jul 16, 2015 3:59:57 PM org.apache.tomcat.util.net.JIoEndpoint$Acceptor run
SEVERE: Socket accept failed
java.net.SocketException: Too many open files
    at java.net.PlainSocketImpl.socketAccept(Native Method)
    at java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:404)
    at java.net.ServerSocket.implAccept(ServerSocket.java:545)
    at java.net.ServerSocket.accept(ServerSocket.java:513)
    at org.apache.tomcat.util.net.DefaultServerSocketFactory.acceptSocket(DefaultServerSocketFactory.java:60)
    at org.apache.tomcat.util.net.JIoEndpoint$Acceptor.run(JIoEndpoint.java:222)
    at java.lang.Thread.null(Unknown Source)

它是开发服务器，每分钟流量少于10个呼叫。

有人建议我应该如何关闭这些连接？