When accessing Tomcat on the local machine, http: // localhost: 8081 cannot be used, but http: // 127.0.0.1: 8081 can be used as a solution?

Step 1: Check the host file in drivers under system32 to check whether 127.0.0.1 localhost exists. If yes, the ing is normal.
Step 2: view the proxy settings of IE, tools-> Internet Options-> connection-> LAN Settings, do not set a proxy for the local machine.
Step 3: Ping localhost in cmd to view the returned result. If the following result is returned:
> Ping localhost
Reply from: 1: Times <1 ms
Reply from: 1: Times <1 ms
Reply from: 1: Times <1 ms
This is because IPv6 is installed. Just uninstall IPv6 and enter "IPv6 Uninstall" in cmd.