java连接mongodb的一个奇葩问题及奇葩解决方式

昨天在eclipse中编写代码，本来连接mongodb进行各项操作都是正常的，但是有一会儿突然之间就没法连接了，还一直抱错，错误如下：

信息: Cluster created with settings {hosts=[192.168.0.4:27017], mode=SINGLE, requiredClusterType=UNKNOWN, serverSelectionTimeout='30000 ms', maxWaitQueueSize=500}十一月 06, 2015 9:23:42 上午 com.mongodb.diagnostics.logging.JULLogger log信息: No server chosen by ReadPreferenceServerSelector{readPreference=primary} from cluster description ClusterDescription{type=UNKNOWN, connectionMode=SINGLE, all=[ServerDescription{address=192.168.0.4:27017, type=UNKNOWN, state=CONNECTING}]}. Waiting for 30000 ms before timing out十一月 06, 2015 9:24:02 上午 com.mongodb.diagnostics.logging.JULLogger log信息: Exception in monitor thread while connecting to server 192.168.0.4:27017com.mongodb.MongoSocketOpenException: Exception opening socketat com.mongodb.connection.SocketStream.open(SocketStream.java:63)at com.mongodb.connection.InternalStreamConnection.open(InternalStreamConnection.java:114)at com.mongodb.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:127)at java.lang.Thread.run(Thread.java:745)Caused by: java.net.SocketTimeoutException: connect timed outat java.net.DualStackPlainSocketImpl.waitForConnect(Native Method)at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:85)at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:339)at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:200)at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:182)at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:172)at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:392)at java.net.Socket.connect(Socket.java:579)at com.mongodb.connection.SocketStreamHelper.initialize(SocketStreamHelper.java:50)at com.mongodb.connection.SocketStream.open(SocketStream.java:58)... 3 more十一月 06, 2015 9:24:12 上午 org.apache.catalina.core.StandardWrapperValve invoke严重: Servlet.service() for servlet [springMVC] in context with path [/birthdaySystem1] threw exception [Request processing failed; nested exception is com.mongodb.MongoTimeoutException: Timed out after 30000 ms while waiting for a server that matches ReadPreferenceServerSelector{readPreference=primary}. Client view of cluster state is {type=UNKNOWN, servers=[{address=192.168.0.4:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketOpenException: Exception opening socket}, caused by {java.net.SocketTimeoutException: connect timed out}}]] with root causecom.mongodb.MongoTimeoutException: Timed out after 30000 ms while waiting for a server that matches ReadPreferenceServerSelector{readPreference=primary}. Client view of cluster state is {type=UNKNOWN, servers=[{address=192.168.0.4:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketOpenException: Exception opening socket}, caused by {java.net.SocketTimeoutException: connect timed out}}]at com.mongodb.connection.BaseCluster.createTimeoutException(BaseCluster.java:370)at com.mongodb.connection.BaseCluster.selectServer(BaseCluster.java:101)at com.mongodb.binding.ClusterBinding$ClusterBindingConnectionSource.<init>(ClusterBinding.java:75)at com.mongodb.binding.ClusterBinding$ClusterBindingConnectionSource.<init>(ClusterBinding.java:71)at com.mongodb.binding.ClusterBinding.getReadConnectionSource(ClusterBinding.java:63)at com.mongodb.operation.OperationHelper.withConnection(OperationHelper.java:166)at com.mongodb.operation.FindOperation.execute(FindOperation.java:394)at com.mongodb.operation.FindOperation.execute(FindOperation.java:57)at com.mongodb.Mongo.execute(Mongo.java:738)at com.mongodb.Mongo$2.execute(Mongo.java:725)at com.mongodb.DBCursor.initializeCursor(DBCursor.java:815)at com.mongodb.DBCursor.hasNext(DBCursor.java:149)at services.servicesImp.UserServiceImp.findUserName(UserServiceImp.java:60)at controllers.UserController.login(UserController.java:43)at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)at java.lang.reflect.Method.invoke(Method.java:606)at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:221)at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:137)at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:110)at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandleMethod(RequestMappingHandlerAdapter.java:777)at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:706)at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:85)at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:943)at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:877)at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:966)at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:857)at javax.servlet.http.HttpServlet.service(HttpServlet.java:620)at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:842)at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:303)at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:241)at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:208)at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:220)at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:122)at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:170)at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:116)at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:316)at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)at java.lang.Thread.run(Thread.java:745)

对于这个问题，查了好多的资料硬是没能解决。后来偶然间关掉了QQ管家里边开启的“免费wifi”，没想到连接就一下子正常了。

于是，我有试了若干次，结果竟然都是一开这个wifi，mongodb立马就连不上，一关掉然后就一切正常。

问题解决了，但根本原因还是不曾明白。