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Session 2
Using JSP Tags
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 2 of 45
Session Objectives
Describe the various elements of
a JavaServer Page
Describe the various JSPTags in
brief
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 3 of 45
What does a JSP look like?
Three main JSP constructs:
Directives
Allows one to control structure of the servlet
Scripting Elements
Used to include Java code
Actions
Specific tags that affect the runtime behavior of the
JSPs
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 4 of 45
An Example
<HTML>
<HEAD><TITLE>MyFirstProgram.jsp</TITLE></HEAD>
<BODY>
<! MyFirstProgram.JSP >
<%@ page import = "java.util.Date" %>
<% out.println("Hello there!"); %> <Br>
<%= "Current date is " + new Date() %>
</BODY> </HTML>
Fixed Template
data
JSP
Directive
JSP
Expression
JSP
Scriptlet
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 5 of 45
What happens under the hood?
User
Request
Web Server/
Servlet Engine
JSP Handler Servlet
(Page Compilation Servlet)
New or
modified file?
Compile into
Servlet
Execute
Servlet
Yes
No
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 6 of 45
Various Elements in a JSP
Directives
page
Defines information that will be globally available for a
JSP
include
Used to insert text and code at JSP translation time
taglib
Defines a mechanism for extending the current set of
JSP tags
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 7 of 45
Different Attributes of the
Page Directive
Attribute Definition
language =
”<scriptingLanguage>”
This attribute tells the server about the language to be
used to complete the JSP file. At present, Java is the only
language that can be used.
extends =
”<className>"
This attribute defines the parent class that the generated
servlet will extend.
import =
”<importList>"
This attribute defines the list of packages that will be
available to this JSP. However, a comma must separate
each package.
session = "true | false" This attribute determines whether the session data will be
available to this page. The default is true.
buffer = "none | <size
in kb>"
This attribute determines whether the output stream is
buffered. The default value is 8 kb.
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 8 of 45
Different Attributes of the
Page Directive – (1)
Attribute Definition
autoFlush = "true |
false"
Determines whether the output buffer will be flushed
automatically, or whether it will raise an exception
when the buffer is full. The default is true.
isThreadSafe = "true
| false"
Specifies whether page can service more than one
request at a time. The default is true.
info = ”<text>" Specifies information about the JSP, can be accessed
by Servlet.getServletInfo().
errorPage =
”<error_URL>"
This attribute represents the relative URL to the JSP
that will handle exceptions.
isErrorPage = "true |
false"
This attribute states whether or not the JSP is an
errorPage. The default is false.
contentType =
”<ctinfo>"
This attribute represents the MIME type and
character set of the response.
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 9 of 45
Using page Attributes - An
example
<%@ page language = "java"
import = "java.rmi.*, java.util.*"
session = "true"
buffer = "12kb"
autoFlush = "true"
info = "page directive jsp"
errorPage = "Error.jsp"
isErrorPage = "false"
isThreadSafe = "false" %>
<HTML> <TITLE> JSP Elements </TITLE>
<HEAD> <H1> JSP Elements </H1> </HEAD>
<BODY> </BODY> </HTML>
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 10 of 45
More on Directives
include directive
Syntax
<%@ include file = “relativeURLspec” %>
taglib directive
Syntax
<%@ taglib uri = “tagLibraryURI”
prefix = “tagPrefix” %>
[...]... < /jsp: include> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 24 of 45 Employeeinfo .jsp eACCP2003/Dynamic Pages Using JSP/ Session 2/ 21 of 45 JSP. .. usually JavaBeans eACCP2003/Dynamic Pages Using JSP/ Session 2/ 19 of 45 JSP Standard Actions – (1) Associates an instance of a pre-defined JavaBean with a given scope and ID Sets the value of a bean’s property Accesses... Enables the JSP engine to dispatch the current request to a static resource, a servlet, or to another JSP at runtime The syntax is as follows: < /jsp: forward> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 26 of 45 Using - An Example s Forward .jsp Using the JSP Forward action... eACCP2003/Dynamic Pages Using JSP/ Session 2/ 31 of 45 } Using - An Example (1) UsePlugin .jsp < /jsp: plugin> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 32 of 45 JSP Standard Actions – (6) JSP actions have the following characteristics: These tags are case-sensitive... request.getParameter("employee")); out.println("Title:" + request.getParameter("title")); %> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 28 of 45 Forward .jsp eACCP2003/Dynamic Pages Using JSP/ Session 2/ 22 of 45 Using - An Example This JSP will search for an employee’s... ((request.getParameter("companyID")).equals("1")) {%> < /jsp: forward> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 27 of 45 Using - An Example – (1) MarthaHome .jsp < /jsp: plugin> eACCP2003/Dynamic Pages Using JSP/ Session 2/ 30 of 45 Using - An Example HelloApplet.java public class HelloApplet extends JApplet { public HelloApplet()... Pages Using JSP/ Session 2/ 16 of 45 JSP Scripting Elements – (5) Declarations are the definition of class-level variables and methods that are used in a JSP Syntax: Example: Declaration This page has been accessed time(s) since the server was rebooted eACCP2003/Dynamic Pages Using JSP/ Session 2/ 17 of 45 JSP Scripting .
Session 2
Using JSP Tags
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 2 of 45
Session Objectives
Describe the various. Page
Describe the various JSP Tags in
brief
eACCP2003/Dynamic Pages Using JSP/ Session 2/ 3 of 45
What does a JSP look like?
Three main JSP constructs:
Directives
Allows