when I restart my server using eclispe, "maxHttpHeader" disappears
Using eclipse WTP, your tomcat server configuration is not (only) stored in the conf folder for tomcat installation.
Go to the "Servers" view and double-click on your server, in the "General Information" section you will find the "Path to the configuration" field, pointing to the configuration directory. This is usually a folder in a separate eclipse project (called a server).
After editing server.xmlthere, you can synchronize your server (in the "Servers" view), and the changes should no longer disappear.
: maxHttpHeader: maxHttpHeader 8080 8443. https. 8443.