Categories: JSPTutorial

JSP pageContext Object

JSP pageContext Object is implicitly available to the developer on Java Server Pages. A pageContext implicit object is used for storing and retrieving page-related information and sharing objects within the same translation unit and same request. Also used as a convenience class that maintains a table of all the other implicit objects.

It stores referece to the implicit objects-
The following example shows how PageContext is used to populate other implicit objects.

public void _jspService (HttpServletRequest request, HttpServletResponse response)
    throws java.io.IOException, ServletException { 

     ... 
    try { 

         ... 
        application = pageContext.getServletContext ();
        config = pageContext.getServletConfig ();
        session = pageContext.getSession ();
        out = pageContext.getOut (); 
         ... 

    } catch (Throwable t) {
         ... 
    } finally {
         ... 
    }
}

Provides convenience methods to get and set attributes in different scopes-
This example uses attributes to save and retrieve data in each of the four scopes:

<%
  // Save data
  pageContext.setAttribute("attr1", "value0");  // PAGE_SCOPE is the default
  pageContext.setAttribute("attr2", "value1", PageContext.PAGE_SCOPE);
  pageContext.setAttribute("attr3", "value2", PageContext.REQUEST_SCOPE);
  pageContext.setAttribute("attr4", "value3", PageContext.SESSION_SCOPE);
  pageContext.setAttribute("attr5", "value4", PageContext.APPLICATION_SCOPE);
%>
    
<%-- Show the values --%>
<%= pageContext.getAttribute("attr1") %>
<%= pageContext.getAttribute("attr2", PageContext.PAGE_SCOPE) %>
<%= pageContext.getAttribute("attr3", PageContext.REQUEST_SCOPE) %>
<%= pageContext.getAttribute("attr4", PageContext.SESSION_SCOPE) %>
<%= pageContext.getAttribute("attr5", PageContext.APPLICATION_SCOPE) %>

JSP pageContext Object Example:

<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
    pageEncoding="ISO-8859-1"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<title>JSP pageContext Object Example</title>
</head>
<body>
<%  
 JspWriter pw =  pageContext.getOut();
  pw.print("Hello Dinesh....This is another example of JSP 'pageContext' object");
%>
</body>
</html>

As you can see above, using JSP pageContext object, JspWriter instance is created. Using this JspWriter object, String response is set that displayed on the browser when JSP served a request.

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Dinesh Rajput

Dinesh Rajput is the chief editor of a website Dineshonjava, a technical blog dedicated to the Spring and Java technologies. It has a series of articles related to Java technologies. Dinesh has been a Spring enthusiast since 2008 and is a Pivotal Certified Spring Professional, an author of a book Spring 5 Design Pattern, and a blogger. He has more than 10 years of experience with different aspects of Spring and Java design and development. His core expertise lies in the latest version of Spring Framework, Spring Boot, Spring Security, creating REST APIs, Microservice Architecture, Reactive Pattern, Spring AOP, Design Patterns, Struts, Hibernate, Web Services, Spring Batch, Cassandra, MongoDB, and Web Application Design and Architecture. He is currently working as a technology manager at a leading product and web development company. He worked as a developer and tech lead at the Bennett, Coleman & Co. Ltd and was the first developer in his previous company, Paytm. Dinesh is passionate about the latest Java technologies and loves to write technical blogs related to it. He is a very active member of the Java and Spring community on different forums. When it comes to the Spring Framework and Java, Dinesh tops the list!

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