The tomcat is configured internally in centos7, but it is not accessible from outside

I recently set up a centos7 virtual machine, and ran tomcat, docker and rabbitMQ during the interview.
At the beginning, I used the openJDK that comes with the system. Initially, it can be successfully built, and then in windows, you can access tomcat by accessing the ip address of the virtual machine. But after restarting the virtual machine, life and death cannot be accessed. I uninstalled tomcat and reinstalled it. The firewall and ports of centos were configured successfully, but tomcat was still not accessible.
I asked a colleague and said that it might be because of the problem with the java environment that comes with centos, and asked me to reinstall a linux jdk.
Then I refer to the jdk installation tutorial , successfully installed and configured my java environment, and then I can access it when I reinstall tomcat.