Jsp scripting elements

• Jsp scripting elements are used to embed jva code in to the jsp.
• Jsp scripting elements are three types
  
  1. Declaration
  2. Expression
  3. Scriplet
  
  

Jsp Declaration:

• Jsp declaration is one of the three scripting elements.
• it is used to embed java code into the jsp

• A Jsp declration starts with "<%!" and ends with "%>".
• <%! int a%>.
• Instance variables, instance methods, static methods can be declared and defined in ajsp declaration.
• During translation time of jsp they became members of container generated servlate/page implementation class.

Jsp Expression:

• Jsp Expression is one of the three scripting elements.
• it is used to embed java code into the js.
• A jsp expression starts with "<%=" and ends with "%>".
• <%=a+b%>
• within a Jsp expression only one java expression that too without semicolon is placed.
• When Jsp expression is evaluated two thing will happen in the backend
  
  1. Java expression is evaluated
  2. The result is sent to the browser stream.
•  we can have any number of jsp expressions in ajsp.
• During translation phase each java expression of a jsp expression is placed in into _jspService()
  method of page implemented class

Jsp Scriplet:

• Jsp scriplet is one of the three scripting elements.
• it is used to embed java code into the js.
• A jsp scriplet starts with "<%" and ends with "%>".
• <% java code%>
• To serve the client request what ever java code required that is placed in servlet.
• In servlet programming whatever code we write in the service() method of user defined servlet all that code can be placed in a jsp scriplet.
• During the translation phase java code placed in the scriplet is written in to _jspService() method of page implementation class.
• in jsp we can have any number of scriplets.