Eclipse Mars configure tomcat 7

Enter Eclipse, click "Window" --> "Preferences".
In the left panel of the pop-up window that appears, select "Server" --> "Runtime Environments".
Click "Add.." on the right, select "tomcat 7.0", click "next",
and then select the installation location of Tomcat in "Tomcat installation directory", mine is

D:\Program Files\apache-tomcat-7.0.86

Click "Finish".