Who can tell me the fundamental about convert jsp to servlet?for example, "<%! ... %>" is converted to what and "<%= ... %>" is converted to what,etc.
Depending on your servlet engine, the java source files generated by the pageCompile servlet is available for you. Some servlet engines will require a special config parameter to keep the source file when a jsp is compiled into a servlet by pageCompile.
Take a look at the source of the servlet and compare it to your jsp and you'll have all the translation there. It is not good practice to edit the generated servlet source of course.