From: http://www.diybl.com/course/3_program/java/javajs/20090425/165326.html
<% @ Include file = "1.jsp" %>
<JSP: Include page = "2.jsp"> </jsp: Include>
There are two methods to include JSP files. The first method to include a file is. when the content in the JSP file is copied together to the file to be included, we all know that JSP is actually converted to servlet for parsing and running. The specific storage location is % cataline_tomcat % \ work \ Catalina \ webapps. When we run a JSP file, we will find the Java source file and the compiled class file in some directories. If it is the first type of include file, it means that the class file before the Java source file is not generated under the current directory, and the second type of include will generate some files under some directories.
From this perspective, the first method should be to compile the source code together into the file to be included, and the second is to return the compiled file results to the file to be included.