Basic JSP scripting elements

Contributed by qmchenry January 23, 2004  
Tagged: JSP programming

JavaServer Pages (JPSs) offer a number of ways to inject Java code into the Servlet code generated when a JSP is compiled.

Scriptlet code elements put the included Java code into the _jspService method. The included code needs to be complete java code (remember the trailing semicolons):

exciting HTML code
<% String important = new String("Very important programmer"); %>
more HTML code

Expressions are evaluated and placed into out.print() methods to be written to the output stream. The code included is an expression, not a complete Java statement, so leave off the trailing semicolon:

HTML tags
<%= important %>
HTML tags
<%= new java.util.Date() %>


Declaration elements insert the enclosed code into the body of the servlet code allowing the declaration of variables or methods:

HTML stuff
<%! private int counter = 0; %>