What Are Implicit Objects

This section describes implicit objects that are created by the JSP/Servlet container: out, request, response, pageContext, session, application, and config.

What Are Implicit Objects? Implicit objects are data objects are created by the JSP/Servlet container so that you can use them interact with the execution environment.

Here is a list of implicit objects supported in JSP 2.1:

Some commonly used methods provided by those implicit objects are listed below:

// Insert a string into the outgoing response body
out.println(String string); 

// Retrieve all cookies as an array from the incoming request
request.getCookies();

// Retrieve the query string included in the request URL
request.getQueryString()

// Add a cookie to the outgoing response
response.addCookie(Cookie cookie)

// Set a HTTP header to the outgoing response
response.setHeader(String name, String value)

// Retrieve the session ID associated with this session
session.getId();

// Save an object into the session for later use
session.setAttribute(String name, Object value);

// Retrieve an object previously saved in the session
session.getAttribute(String name);

// Retrieve the name and version of the Servlet container
application.getServerInfo()

// Save an object into the application for other Servlets
application.setAttribute(String name, Object value);

// Retrieve an object previously saved by other Servlets
application.getAttribute(String name);

Last update: 2012.

Table of Contents

 About This Book

 JSP (JavaServer Pages) Overview

 Tomcat 7 Installation on Windows Systems

 JSP Scripting Elements

 Java Servlet Introduction

JSP Implicit Objects

What Are Implicit Objects

 Information of JSP Execution Context

 Information from "request" Object

 Methods Supported by the "session" Object

 Syntax of JSP Pages and JSP Documents

 JSP Application Session

 Managing Cookies in JSP Pages

 JavaBean Objects and "useBean" Action Elements

 Managing HTTP Response Header Lines

 Non-ASCII Characters Support in JSP Pages

 Performance of JSP Pages

 EL (Expression Language)

 Overview of JSTL (JSP Standard Tag Libraries)

 JSTL Core Library

 JSP Custom Tags

 JSP Java Tag Interface

 Custom Tag Attributes

 Multiple Tags Working Together

 File Upload Test Application

 Outdated Tutorials

 References

 PDF Printing Version