The reason for not supporting is that the version of eclipse is too low, here is the download link of the latest version (that is, supporting tomcat9.0 version).
Link: https://pan.baidu.com/s/1_6STWXhhkSmVXbtWzy6jyQ
Extraction code: hvyv
After downloading the file, select the file at the beginning of Eclipse IDE to download, namely: 
run it.
If this error occurs when starting tomcat:
Several ports (8005, 8080, 8009) required by Tomcat v9.0 Server at
localhost are already in use. The server may already be running in
another process, or a system process may be using the port. To start
this server you will need to stop the other process or change the port
number(s).
which is:
Solution:
Find the process with this name in the task manager (the process names are in lexicographical order), and end the task. It can run successfully.
