JSP Tutorial


Your first JSP

  JSP simply puts Java inside HTML pages.  You can take any existing HTML page and change its extension to ".jsp" instead of ".html".  In fact, this is the perfect exercise for your first JSP.

Take the HTML file you used in the previous exercise.  Change its extension from ".html" to ".jsp".  Now load the new file, with the ".jsp" extension, in your browser.

You will see the same output, but it will take longer!  But only the first time.  If you reload it again, it will load normally.

What is happening behind the scenes is that your JSP is being turned into a Java file, compiled and loaded.  This compilation only happens once, so after the first load, the file doesn't take long to load anymore.  (But everytime you change the JSP file, it will be re-compiled again.)

Of course, it is not very useful to just write HTML pages with a .jsp extension!  We now proceed to see what makes JSP so useful.