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Java Server Pages (JSP) scripting elements and variables"

JSP scripting elements and variables

Standard scripting variables

• out – The JSPWriter used to write the data to the response stream.
• page – The servlet itself.
• pageContext – A PageContext instance that contains data associated with the whole page. A given HTML page may be passed among multiple JSPs.
• request – The HTTP request object.
• response – The HTTP response object.
• session – The HTTP session object that can be used to track information about a user from one request to another.

Scripting elements

• A declaration tag places a variable definition inside the body of the java servlet class. Static data members may be defined as well.
  <%! int serverInstanceVariable = 1; %>
• A scriptlet tag places the contained statements inside the _jspService() method of the java servlet class.
  <% int localStackBasedVariable = 1; out.println(localStackBasedVariable); %>
• An expression tag places an expression to be evaluated inside the java servlet class. Expressions should not be terminated with a semi-colon.
  <%= "expanded inline data " + 1 %>