错误信息：
Details:Timed out after 30000 ms while waiting to connect. Client view of cluster state is {type=UNKNOWN, servers=[{address=192.168.168.147:27017, type=UNKNOWN, state=CONNECTING, exception={com.mongodb.MongoSocketOpenException: Exception opening socket}, caused by {java.net.ConnectException: Connection refused: connect}}]解决方法：
mongodb 连接的IP地址修改为:127.0.0.1
mongodb 默认绑定本地连接，不支持远程连接