Servlet and servlet-mapping tags in the servlet Project Web. xml

Extract the Web. xml file fragment of a project:

The access order is 1->2->3->4, where the values of 2 and 3 must be the same.

The value in the Url-pattern tag is the URL to be entered in the browser's address bar, which can be named by itself, which accesses a servlet named Servlet-name, and the value of the two Servlet-name tags must be the same because the values in the servlet tag The Servlet-name tag maps to the value in the Servlet-class tag and ultimately accesses the class in the Servlet-class tag.

Also, the/Expression of Web. http://localhost:8080/+ project Name
Instead, the. JSP page has an action that adds/represents an absolute path http://localhost:8080/, and no plus/indicates a relative path

Servlet and servlet-mapping tags in the servlet Project Web. xml