• One or more statements that are executed each time the page is requested.


• you can also insert variable and method declarations, Java expressions, and so on in scriptlet.

Syntax:-

<% Java Code or statement %>

Example:-

Totam sum:-<% 12+12 %>
output:-
24

• In Servlet you learned,how to use such objects as HttpServletRequest, HttpServletResponse, HttpSession, and ServletContext.


• JSPs follow same rules as servlets,they also need to be able to get access to these objects.


• JSPs have a number of predefined variables that give you access to these objects.

There are following implicit object and their names along with the corresponding JSP variables:-

1)request:-

This variable use to access the HttpServletRequest object.

Example:-

				
    <% String name=request.getParamter("name"); %>
			

2)response:-

This variable use to access the HttpServletReponse object.

Example:-

   <% response.setContentType("text/html"); %>
			

3)out:-

This variable use to access the JspWriter class which has same as PrintWriter in Servlet.

Example:-

   <% out.println("This is implicit Object"); %>

4)session:-

This variable provide the instance of the HTTPSession object.

5)exception:-

This variable provide an instance of Throwable object and shows error information which is only available from the JSP error page that contains the directive isErrorPage=true.

6)page:-

This variable provide the instance of the JSP's Java class which processes the current request.

7)pageContext:-

This variable presents the javax.servlet.jsp.PageContext class,which have methods for communicate with scoped data.

8)application:-

This variable provides you access to the ServletContext object without calling getServletConfig().getContext().

9)config:-

This variable provides access servletConfig()object and give configuration information about JSP.

JSP actions provide runtime instructions to the JSP Containers e.g- a JSP action can include a file, forward a request to another page or create an instance of a JavaBean.

jsp:include:-

jsp:include action adds the content of the included page at the runtime.

<jsp:include page="login.jsp" />

jsp:forward:-

forward action enables you to redirect the program flow to a different HTML file, JSP or servlet while maintaining the same request and response objects. This directive works as the forward() method of the RequestDispatcher.

<jsp:forward page="welcome.jsp" />

Java Beans:-

JavaBeans are used for data exchange, and help to separate business logic from presentation.

A JavaBean is a Java class that has following signature accessing the bean's properties.
->no-arguments constructor.
->private or protected fields (properties)
->public setter/getter methods .

Properties of JavaBean:-

1)jsp:useBean:-

Creates or re-uses a JavaBean available to the JSP page. Attributes supported are Id/ Class/Scope/Type/beanName.

<:useBean id="User" class="com.web.JSPExam" />
	

2)jsp:getProperty:-

Gets a property from the specified JavaBean.

3) jsp:setProperty:-

Sets a property in the specified JavaBean. Attributes supported are name/ property / param /value.

	<jsp:useBean id="Student" class="com.web.FirstJsp" />

<jsp:setProperty name="Student" property="LastName" value="Dwivedi" />

<jsp:setProperty name="Student" property="FirstName" value="Shivank" />