com.mongodb.MongoSocketOpenException: Exception opening socket
at com.mongodb.internal.connection.SocketStream.open(SocketStream.java:70) ~[mongodb-driver-core-4.0.6.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.open(InternalStreamConnection.java:127) ~[mongodb-driver-core-4.0.6.jar:na]
at com.mongodb.internal.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:117) ~[mongodb-driver-core-4.0.6.jar:na]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_311]
Caused by: java.net.SocketTimeoutException: connect timed out
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) ~[na:1.8.0_311]
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:81) ~[na:1.8.0_311]
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:476) ~[na:1.8.0_311]
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:218) ~[na:1.8.0_311]
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:200) ~[na:1.8.0_311]
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:162) ~[na:1.8.0_311]
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:394) ~[na:1.8.0_311]
at java.net.Socket.connect(Socket.java:606) ~[na:1.8.0_311]
at com.mongodb.internal.connection.SocketStreamHelper.initialize(SocketStreamHelper.java:63) ~[mongodb-driver-core-4.0.6.jar:na]
at com.mongodb.internal.connection.SocketStream.initializeSocket(SocketStream.java:79) ~[mongodb-driver-core-4.0.6.jar:na]
at com.mongodb.internal.connection.SocketStream.open(SocketStream.java:65) ~[mongodb-driver-core-4.0.6.jar:na]
... 3 common frames omitted
MongoDB连接超时，首先先检查一下spring的application.properties配置文件有没有写错：
spring:
data:
mongodb:
host: xx.xx.xx.xx
port: 27017
database: xxx
username: xxx
password: xxx确保配置文件无错，还需要关闭主机的防火墙，如果是服务器不要忘记了开放27017的端口号。
ok搞好了，接下来又报了一个错误：
com.mongodb.MongoSocketOpenException: Exception opening socket
at com.mongodb.internal.connection.SocketStream.open(SocketStream.java:70) ~[mongodb-driver-core-4.0.6.jar:na]
at com.mongodb.internal.connection.InternalStreamConnection.open(InternalStreamConnection.java:127) ~[mongodb-driver-core-4.0.6.jar:na]
at com.mongodb.internal.connection.DefaultServerMonitor$ServerMonitorRunnable.run(DefaultServerMonitor.java:131) ~[mongodb-driver-core-4.0.6.jar:na]
at java.lang.Thread.run(Thread.java:748) [na:1.8.0_311]
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.DualStackPlainSocketImpl.waitForConnect(Native Method) ~[na:1.8.0_311]
at java.net.DualStackPlainSocketImpl.socketConnect(DualStackPlainSocketImpl.java:81) ~[na:1.8.0_311]
at java.net.AbstractPlainSocketImpl.doConnect(AbstractPlainSocketImpl.java:476) ~[na:1.8.0_311]
at java.net.AbstractPlainSocketImpl.connectToAddress(AbstractPlainSocketImpl.java:218) ~[na:1.8.0_311]
at java.net.AbstractPlainSocketImpl.connect(AbstractPlainSocketImpl.java:200) ~[na:1.8.0_311]
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:162) ~[na:1.8.0_311]
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:394) ~[na:1.8.0_311]
at java.net.Socket.connect(Socket.java:606) ~[na:1.8.0_311]
at com.mongodb.internal.connection.SocketStreamHelper.initialize(SocketStreamHelper.java:63) ~[mongodb-driver-core-4.0.6.jar:na]
at com.mongodb.internal.connection.SocketStream.initializeSocket(SocketStream.java:79) ~[mongodb-driver-core-4.0.6.jar:na]
at com.mongodb.internal.connection.SocketStream.open(SocketStream.java:65) ~[mongodb-driver-core-4.0.6.jar:na]
... 3 common frames omitted
出现了连接被拒绝，这个问题很简单，是因为MongoDB的配置文件默认是本地ip访问，需要改配置文件，而不是说在application启动类上去排除某些配置类。
在mongodb/config.conf文件，找到如下配置：
bindIp 改成 0.0.0.0