JSP Handout v1.0

8/4/2019 JSP Handout v1.0

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Handout: JSPVersion: JSP/Handout/0408/1.0

Date: 04-04-08

Cognizant

500 Glen Pointe Center West

Teaneck, NJ 07666

Ph: 201-801-0233

www.cognizant.com
http://www.cognizant.com/http://www.cognizant.com/


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TABLE OF CONTENTS

Introduction ...................................................................................................................................5About this Module .........................................................................................................................5Target Audience ...........................................................................................................................5Module Objectives ........................................................................................................................5Pre-requisite .................................................................................................................................5

Session 02: Understanding JSP ..................................................................................................6Learning Objectives ......................................................................................................................6What is a JSP page? ....................................................................................................................6When to use Servlet and when JSP .............................................................................................6Summary ......................................................................................................................................6Test Your Understanding ..............................................................................................................6

Session 03: Sample JSP ................................................................................................................7Learning Objectives ......................................................................................................................7Try It Out .......................................................................................................................................7Summary ......................................................................................................................................7Test your Understanding ..............................................................................................................7

Session 04: JSP Architecture Model ............................................................................................8Learning Objectives ......................................................................................................................8JSP Model 1 Architecture .............................................................................................................8JSP Model 2 Architecture .............................................................................................................8Summary ......................................................................................................................................9Test your Understanding ..............................................................................................................9

Session 05: JSP Syntax elements ..............................................................................................10Learning Objectives ....................................................................................................................10JSP Element:

JSP Expression ...............................................................................................10

JSP Element: JSP Expression ...............................................................................................10JSP Element: JSP Scriptlet ....................................................................................................10JSP Element: JSP Declaration ..............................................................................................10JSP Element: JSP page Directive ..........................................................................................10JSP Element: JSP include Directive ......................................................................................10JSP Element: JSP Comment .................................................................................................10JSP Element: jsp:include Action .................................................................................................11Try It Out .....................................................................................................................................11

Page 2Copyright 2007, Cognizant Technology Solutions, All Rights Reserved

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Summary ....................................................................................................................................11Test your Understanding ............................................................................................................11

Session 07: Understanding JSP Page Directives .....................................................................12Learning Objectives ....................................................................................................................12

JSP Page Directives ...................................................................................................................12Try It Out .....................................................................................................................................13Summary ....................................................................................................................................14Test your Understanding ............................................................................................................14

Session 10: JSP Page Life Cycle ................................................................................................15Learning Objectives ....................................................................................................................15JSP Page Life Cycle ...................................................................................................................15Summary ....................................................................................................................................15Test your Understanding ............................................................................................................15

Session 12: JSP Model - Advanced ............................................................................................16Learning Objectives ....................................................................................................................16Translation process ....................................................................................................................16JSP Pages as XML Documents .................................................................................................16Try It Out .....................................................................................................................................16Summary ....................................................................................................................................17Test your Understanding ............................................................................................................17

Session 13: JSP Implicit Variables and Objects .......................................................................18Learning Objectives ....................................................................................................................18JSP Implicit Variables and Objects .............................................................................................18Request ......................................................................................................................................18Response ....................................................................................................................................18Session .......................................................................................................................................18Config .........................................................................................................................................19Application ..................................................................................................................................19Page ...........................................................................................................................................19PageContext ...............................................................................................................................19Try It Out .....................................................................................................................................19Summary ....................................................................................................................................20Test your Understanding ............................................................................................................20

Session 16: JSP Page Scopes ....................................................................................................21Learning Objectives ....................................................................................................................21


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JSP Page Scopes .......................................................................................................................21Try It Out .....................................................................................................................................21Summary ....................................................................................................................................22Test your Understanding ............................................................................................................23

Session 18: JSP Static and Dynamic Inclusions ......................................................................24Learning Objectives ....................................................................................................................24Static Inclusions ..........................................................................................................................24Dynamic Inclusions .....................................................................................................................24Try It Out .....................................................................................................................................24Summary ....................................................................................................................................25Test your Understanding ............................................................................................................25

Session 21: Java Beans with JSP Scriptlets .............................................................................26Learning Objectives ....................................................................................................................26JavaBeans ..................................................................................................................................26JavaBeans Component Design Conventions: ............................................................................26JavaBeans Component property: ...............................................................................................26Syntax: ........................................................................................................................................26Try It Out .....................................................................................................................................27Summary ....................................................................................................................................28Test your Understanding ............................................................................................................28

Session 22: Java Beans with JSP Actions ................................................................................29Learning Objectives ....................................................................................................................29Java Beans and JSP ..................................................................................................................29Creating and Using a JavaBeans Component: ..........................................................................29Setting JavaBeans Component Properties: ...............................................................................29Retrieving JavaBeans Component Properties: ..........................................................................29Try It Out .....................................................................................................................................29Summary ....................................................................................................................................30

Test your Understanding ............................................................................................................31

References ....................................................................................................................................32Websites .....................................................................................................................................32Books ..........................................................................................................................................32

STUDENT NOTES: ........................................................................................................................33


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Introduction

About this Module

This module provides an overview about following topics:

An introduction to JSP

Basic concepts of JSP

Custom Tags and Libraries

Target Audience

This module is designed for the entry level trainees.

Module Objectives

After completing this module, you will be able to:

Work with JSP

Explain JSP Model: Basics

Describe JSP Model: Advanced

Work with Java Beans

Identify Custom Tags and Libraries

Pre-requisite

This module is designed for the trainees having basic knowledge on java.


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Session 02: Understanding JSP

Learning Objectives

After completing this session, you will be able to:

Comprehend the JSP Page

Identify the time to use Servlet and JSP

What is a JSP page?

JSP page is a text-based document that contains two types of text:

Static template data: It can be expressed in any text-based format, such as HTML,

SVG, WML, and XML.

JSP elements: It constructs dynamic content.

When to use Servlet and when JSP

1. JSP is used for presentation stuff and servlets are used for control and business logic

stuff. They are good for non-HTML content, such as a file download servlet or a chart

generating servlet, because it is simpler to deal with that content in servlets.

2. In JSP, anything between %> and


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Session 03: Sample JSP

Learning Objectives


Create a simple JSP

Try It Out

Problem Statement:

Write a program to that prints this is an example for template text using html template, this is an

example of expression using JSP expression and this is an example of scriplet

Code:

My Title

This is an example for template text

How It Works:

Based upon the style it will prints

Summary

A JSP page is a text-based document that contains two types of text.

Static template data, which can be expressed in any text-based format, such as

HTML, SVG, WML, and XML. JSP elements construct dynamic content.

Test your Understanding

1. What is a JSP Page?

2. Differentiate between template text, scriplet, and expression


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Session 04: JSP Architecture Model

Learning Objectives


Comprehend a JSP Page

Differentiate between various JSP architectural models

Compare the merits and demerits of different models

JSP Model 1 Architecture

The JSP page alone is responsible for processing the incoming request and replying back to the

client.

Merits:

1. Simple

2. Separation of presentation from content

Demerits:

It may not be desirable for complex implementations.

While this may not seem to be much of a problem for Java developers, it is certainly

an issue if your JSP pages are created and maintained by designers, which is usually

the norm on large projects.

JSP Model 2 Architecture

1. Hybrid approach for serving dynamic content, since it combines the use of both servlets

and JSP.

2. Here, the servlet acts as the controller and is in charge of the request processing and the

creation of any beans or objects used by the JSP, as well as deciding, depending on the

users actions, which JSP page to forward the request to..

3. Note particularly that there is no processing logic within the JSP page itself.

4. It is simply responsible for retrieving any objects or beans that may have been previously

created by the servlet, and extracting the dynamic content from that servlet for insertion

within static templates

Merits:

1. Makes use of the predominant strengths of both technologies, using JSP to generate the

presentation layer and servlets to perform process-intensive tasks. Separation of

presentation from content

2. Cleanest separation of presentation from content, leading to clear delineation of the roles

and responsibilities of the developers and page designers on your programming team.


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Summary

JSP Model 1 Architecture: The JSP page alone is responsible for processing the

incoming request and replying back to the client. Separation of presentation from

content.

JSP Model 2 Architecture: Makes use of the predominant strengths of both

technologies, using JSP to generate the presentation layer and servlets to perform


1. What is a JSP Page?

2. When will you use Servlet and when JSP?


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Session 05: JSP Syntax elements

Learning Objectives


Explain the syntax to be followed for different JSP elements

JSP Element: JSP Expression


Syntax:

Interpretation: Expression is evaluated and placed in output.


Syntax:

Interpretation: Expression is evaluated and placed in output..

JSP Element: JSP Scriptlet

Syntax:

Interpretation: Code is inserted in service method.

JSP Element: JSP Declaration

Syntax:

Interpretation: Code is inserted in body of servlet class, outside the service method.

JSP Element: JSP page Directive

Syntax:

Interpretation: Directions to the servlet engine about general setup.

JSP Element: JSP include Directive

Syntax:


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JSP Element: jsp:include Action

Syntax:

Interpretation: Directions to the servlet engine about general setup.

Example:

Try It Out

Problem Statement:

Create wecome.jsp using all the jsp syntax elemts.t

Code:

How It Works:

Based upon the JSP syntax it will work

Summary

JSP Scriptlet: It is inserted in service method.

JSP Declaration: It is inserted in body of servlet class, outside the service method.

JSP Comment: Comment is ignored, when JSP page is translated into servlet.

JSP Expression: Expression is evaluated and placed in output.


1. What are the different JSP elements?


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Session 07: Understanding JSP Page Directives

Learning Objectives


Explain JSP Page Directives

JSP Page Directives

The page directive is used to define attributes that apply to an entire JSP page.

There attributes of page directive are, language, extends, import, session, buffer, autoFlush,

isThreadSafe, info, errorPage, contentType, isErrorPage, pageEncoding, isELIgnored

JSP Page Directives : language

Used for specifying other scripting languages to be used in a JSP page.

JSP Page Directives : extends

Used for specifying some other java classes to be used in a JSP page.

JSP Page Directives : import

Used for importing packages or java classes.

JSP Page Directives : session

Used for controlling session management.

JSP Page Directives : buffer

Used by the out object to handle output generated by the JSP page.

JSP Page Directives : autoFlush

Used for controlling buffer flow.

JSP Page Directives : isThreadsafe

Used to control the request handling feature.

JSP Page Directives : info

Used to set some description for the page..

JSP Page Directives : errorPage

Used to set the error page to be called if any error occurs.

JSP Page Directives : contentType

Used to specify the MIME type.


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JSP Page Directives : isErrorPage

Used to specify if the jsp page is an error page or not

JSP Page Directives : pageEncoding

Used to specify the language that the page uses when the page is sent to the browser.

JSP Page Directives : isELIgnored

Used to control the EL expression evaluation in the JSP page.

Try It Out

Problem Statement:

Create a JSP page containing page directives

Code:

package com.cts;

public class Perform {

public String getWord(){

return "hello world";

}

public void createError(){

int i=10/0;

} }

Page directives demo


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Summary

Attributes are as follows:

language: Used for specifying other scripting languages to be used in a JSP page

extends: Used for specifying some other java classes to be used in a JSP page import: Used for importing packages or java classes

session: Used for controlling session management

buffer: Used by the out object to handle output generated by the JSP page

autoFlush: Used for controlling buffer flow

isThreadSafe: Used to control the request handling feature

info: Used to set some description for the page

errorPage: Used to set the error page to be called if any error occurs

contentType: Used to specify the MIME type

isErrorPage: Used to specify if the JSP page is an error page or not

pageEncoding: Used to specify the language that the page uses when the page is

sent to the browser

isELIgnored: Used to control the EL expression evaluation in the JSP page>


1. What are the important attributes of page directive?


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Session 10: JSP Page Life Cycle

Learning Objectives


Comprehend JSP page life cycle

JSP Page Life Cycle

The three stages of JSP's life cycle are:

Translation: It is where the JSP is converted into a Java file

Compilation: It is where the translated java file is compiled to a class file

Execution: It is where the compiled and initialized Servlet (JSP) handles the requests

Summary

Translation: This is the place, where the JSP is converted into a Java file.

Compilation: This is the place, where the translated java file is compiled to a class

file.

Execution: This is the place, where the compiled and initialized Servlet (JSP) handles

the requests.


1. Explain JSP page life cycle.


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Session 12: JSP Model - Advanced

Learning Objectives


Comprehend translation process

Identify the JSP pages as XML documents

Translation process

The JSP page is first converted into a Java file. This java file is compiled to a class file

and is initialized to handle http requests, just like http Servlet.

The best part is a JSP developer, who need not do this translation manually. The

Servlet container (Tomcat) does this translation.

JSP Pages as XML Documents

A JSP document is an XML document and must comply with the XML standard.

Fundamentally, this means that a JSP document must be well formed, meaning that

each start tag must have a corresponding end tag and that the document must have

only one root element.

In addition, JSP elements included in the JSP document must comply with the XML

syntax.

Try It Out

Problem Statement:

Create JSP named index.jsp with only XML tags. The page should contain a instance variable

named names of type java.util.List. Add three names of your choice to that list. And then iterate

though the list to print on the browser all the contents of the list.

This can be using the following XML tags:

, , and >.

Code:

private List names;

names=new ArrayList();

names.add("abc");

names.add("def");

names.add("ghi");

for(Object temp:names){


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temp

}

Summary

Translation: This is the place, where the JSP is converted into a Java file.

A JSP document is an XML document and must comply with the XML standard.


1. Define the translation process.

2. List JSP pages as XML documents.


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Session 13: JSP Implicit Variables and Objects

Learning Objectives


JSP implicit variables and Objects

JSP Implicit Variables and Objects

Request: An instance of HttpServletRequest

response: An instance of HttpServletResponse

out: An instance of JspWriter

session: An instance of HttpSession

config: An instance of ServletConfig

application: An instance of ServletContext

page: An instance of Object

pageContext: An instance of PageContext

exception: An instance of Throwable

Request

The class or the interface name of the object request is http.httpservletrequest. The object request

is of type Javax.servlet.http.httpservletrequest. This denotes the data included with the HTTP

Request. The client first makes a request that is then passed to the server. The requested object is

used to take the value from clients web browser and pass it to the server. This is performed using

HTTP request like headers, cookies and arguments.

Response

This denotes the HTTP Response data. The result or the information from a request is denoted by

this object. This is in contrast to the request object. The class or the interface name of the object

response is http.HttpServletResponse. The object response is of type Javax.servlet.http.

>httpservletresponse. Generally, the object response is used with cookies. The response object is

also used with HTTP Headers

Session

This denotes the data associated with a specific session of user. The class or the interface name

of the object Session is http.HttpSession. The object Session is of type

Javax.servlet.http.httpsession. The previous two objects, request and response, are used to pass

information from web browser to server and from server to web browser respectively. The Session

Object provides the connection or association between the client and the server. The main use of

Session Objects is for maintaining states when there are multiple page requests. This will be

explained in further detail in following


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Config

This is used to get information regarding the Servlet configuration, stored in the Config object. The

class or the interface name of the Config object is ServletConfig. The object Config is written

Javax.servlet.http.ServletConfig

Application

This is used to share the data with all application pages. The class or the interface name of the

Application object is ServletContext. The Application object is written:

Javax.servlet.http.ServletContext

Page

The Page object denotes the JSP page, used for calling any instance of a Page's servlet. The

class or the interface name of the Page object is jsp.HttpJspPage. The Page object is written:

Java.lang.Object

PageContext

This is used to access page attributes and also to access all the namespaces associated with a

JSP page. The class or the interface name of the object PageContext is jsp.pageContext. The

object PageContext is written: Javax.servlet.jsp.pagecontext

Try It Out

Problem Statement:

Create a jsp named index.jsp. Set attributes in all the 4 possible scopes and try to retrieve them.

Also display on the browser the servlet name using the SerlvetConfig instance.

This sample uses the following implicit variables: request, out, session, config, application

Code:


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How It Works:

The attributes are stored in various scopes and are retrieved and displayed. Servlet name is

displayed to show the config parameter.

Summary


Response: An instance of HttpServletResponse

Out: An instance of JspWriter


Config: An instance of ServletConfig

Application: An instance of ServletContext

Page: An instance of object


Exception: An instance of Throwable


1. What are JSP implicit variables and objects?


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Session 16: JSP Page Scopes

Learning Objectives


JSP Page Scopes

JSP Page Scopes

Page Scope

Request Scope

Session Scope

Application Scope

JSP Page Scopes: Page

This scope helps to keep the data available while the page is loading. Any object whose scope is

defined as page scope will disappear as soon as the response is sent to the browser. The object

with a page scope may be modified as often as desired within the particular page but the changes

are lost as soon as the user moves away from the page. By default all beans have page scope.

JSP Page Scopes: Request

Any object created in the request scope will be available as long as the request object is valid. For

example if the JSP page uses a tag, then the bean will be accessed in the

forwarded page and if redirect is used then the bean is destroyed.

JSP Page Scopes: Session

In JSP terms, the data associated with the user has session scope. A session does not correspond

directly to the user; rather, it corresponds with a particular period of time the user spends at a site.

Typically, this period is defined as all the hits a user makes to a website between starting and

exiting his browser.

JSP Page Scopes: Application

The bean associated with the application scope will be accessible to all the users and all the pages

in the application.

Try It Out

Problem Statement:

Write a web application that has an index page, which takes username from the user.

If submitted, it has to call a servlet, which then calls another jsp. This jsp has to print

the username attached with the request.

System should retrieve the contact email configured as an init param for whole of the

application:


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Code:

Page Scopes Example

Username:

Password:

Index Page

How It Works:

The index.jsp calls the servlet mapped for the submit.do call. The servlet sets the

username as an attribute to the scopes request, session and application.

It then forwards the request to the output.jsp. It then prints the values from the different

scopes.

Summary


Response: An instance of HttpServletResponse

Out: An instance of JspWriter


Config: An instance of ServletConfig

Application: An instance of ServletContext

Page: An instance of object


Exception: An instance of Throwable.


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1. What do you understand by JSP Page Scopes?


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Session 18: JSP Static and Dynamic Inclusions

Learning Objectives


Explain JSP Static and Dynamic Inclusions

Static Inclusions

It can be done using the "include" directive.

Dynamic Inclusions

It can be done using the action tag

Example:

< jsp:include page="included.html"/>

Try It Out

Problem Statement:

Write an index page that includes a header page and a proverb page. The proverb page follows

the header and it displays a proverb, which changes every one hour. The header contains the

name and a logo.

The page should be able to display the header as well as the dynamic proverb page

Code:

Proverb:


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Summary

This session gives an overview of JSP static and dynamic inclusions.

If any of the contents in the jsp page is dynamic, use dynamic includes. In other

conditions static includes helps improve systems performance.


1. What are JSP static and dynamic inclusions?


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Session 21: Java Beans with JSP Scriptlets

Learning Objectives


Explain Java Beans

JavaBeans

JavaBeans components are Java classes that can be easily reused and composed

together into applications.

Any Java class that follows certain design conventions can be a JavaBeans

component.

JavaServer Pages technology directly supports using JavaBeans components withJSP language elements.

You can easily create and initialize beans and get and set the values of their

properties.

JavaBeans Component Design Conventions:

JavaBeans component design conventions govern the properties of the class and govern the

public methods that give access to the properties.

JavaBeans Component property:

A JavaBeans component property can be:

Read/write, read-only, or write-only.

Simple, which means it contains a single value, or indexed, which means it represents

an array of values..

For each readable property, the bean must have a method of the form:

PropertyClass getProperty() { ... }

For each writable property, the bean must have a method of the form:

setProperty(PropertyClass pc) { ... }

Syntax:

One of the ways to set JavaBeans component properties in a JSP page is using a scriptlet.

Retrieving JavaBeans Component Properties:

Example:


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Try It Out

Problem Statement:

Create a jsp named beanscriptlet.jsp and a bean class named Student.java with accessor methods

for name and id.Set the instance variables of the bean class and then get the variables from the

stored request attributes and display in the browser.

Code:

public class Student{

String id = "";

String name = "";

public void setId(String id) {

this.id = id;

}

public String getId() { return id; }

public void setName(String name) {

this.name = name;

}

public String getName() {

return name;

}

Acessing Bean Class Using Scriplet

The Name and Id of the Students are

Name :

Id :

How It Works:

The values for the instance variables are set and stored in the request attribute and the stored

request attributes are later retrieved using scriptlet and then displayed


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Summary

JavaBeans components are Java classes that can be easily reused and composed

together into applications.

Any Java class that follows certain design conventions can be a JavaBeans

component.

JavaServer Pages technology directly supports using JavaBeans components with

JSP language elements.

You can easily create and initialize beans and get and set the values of their

properties.


1. What is a JSP Bean Class?

2. How can you access Bean class from JSP using scriplet?


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Session 22: Java Beans with JSP Actions

Learning Objectives


Access Java Beans using JSP actions

Java Beans and JSP

JavaServer Pages technology directly supports using JavaBeans components with

JSP language elements.

You can easily create and initialize beans and set the values of their properties.

Creating and Using a JavaBeans Component:

JSP page will use a JavaBeans component, using either one of the following formats:

or

.

Setting JavaBeans Component Properties:

Syntax:

Retrieving JavaBeans Component Properties:

Syntax:


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Code:

Acessing Bean Class Using JSP Action

The Name and Id of the Students are

Name :

Id :

package com.cts;

public class Student{

String id = "";

String name = "";

public void setId(String id) {

this.id = id;

}

public String getId() { return id; }

public void setName(String name) {this.name = name;

}

public String getName() {

return name;

}

}

How It Works:

The bean has to be compiled and the class file has to be present in the classpath.

Start the Tomcat server. Access the Beanaction.jsp page from the browser.

The JSP actions aids users develop scripless pages, which is easy in terms of

maintaining and is easily readable.

Summary

JSP technology directly supports using JavaBeans components with JSP language

elements.

You can easily create and initialize beans and set the values of their properties.


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1. What is a JSP Bean Class?

2. How can you access Bean class from JSP using JSP Action?>


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References

Websites

https://cis.med.ucalgary.ca/https/java.sun.com/j2ee/1.3/docs/tutorial/doc/JSPIntro11.ht

ml

Books

Head First Servlets and JSP

SCWCD Exam Study Kit


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STUDENT NOTES: