java链接mongodb出现异常MongoTimeoutException，求破

mongodb操作时出现异常信息如下：

Caused by: com.mongodb.MongoTimeoutException: Timeout waiting for a pooled item after 5000 MILLISECONDS
    at com.mongodb.internal.connection.ConcurrentPool.get(ConcurrentPool.java:127)
    at com.mongodb.connection.DefaultConnectionPool.getPooledConnection(DefaultConnectionPool.java:256)
    at com.mongodb.connection.DefaultConnectionPool.get(DefaultConnectionPool.java:97)
    at com.mongodb.connection.DefaultConnectionPool.get(DefaultConnectionPool.java:86)
    at com.mongodb.connection.DefaultServer.getConnection(DefaultServer.java:77)
    at com.mongodb.binding.ClusterBinding$ClusterBindingConnectionSource.getConnection(ClusterBinding.java:86)
    at com.mongodb.operation.OperationHelper.withConnectionSource(OperationHelper.java:431)
    at com.mongodb.operation.OperationHelper.withConnection(OperationHelper.java:406)
    at com.mongodb.operation.FindOperation.execute(FindOperation.java:709)
    at com.mongodb.operation.FindOperation.execute(FindOperation.java:81)
    at com.mongodb.Mongo.execute(Mongo.java:810)
    at com.mongodb.Mongo$2.execute(Mongo.java:797)
    at com.mongodb.DBCursor.initializeCursor(DBCursor.java:871)
    at com.mongodb.DBCursor.hasNext(DBCursor.java:142)
    at com.mongodb.DBCursor.one(DBCursor.java:680)
    at com.mongodb.DBCollection.findOne(DBCollection.java:831)
    at com.mongodb.DBCollection.findOne(DBCollection.java:794)
    at com.mongodb.DBCollection.findOne(DBCollection.java:741)
    at org.springframework.data.mongodb.core.MongoTemplate$FindOneCallback.doInCollection(MongoTemplate.java:2197)
    at org.springframework.data.mongodb.core.MongoTemplate$FindOneCallback.doInCollection(MongoTemplate.java:2181)
    at org.springframework.data.mongodb.core.MongoTemplate.executeFindOneInternal(MongoTemplate.java:1925)
    ... 18 more

这是哪里配置的不对吗？？？