Web Development with Java

session-confi g
>
<
session-timeout
>
30
session-timeout
>
session-confi g
>
<
welcome-fi le-list
>
<
welcome-fi le
>
index.jsp
welcome-fi le
>
<
welcome-fi le
>
index.html
welcome-fi le
>
<
welcome-fi le
>
index.htm
welcome-fi le
>
welcome-fi le-list
>
web-app
>
Web Application Location
Web applications are run by servlet engines. Each servlet engine will have a special 
location for web applications. For the Tomcat servlet engine, all web applications 
should be located in the 
webapps
directory.
NetBeans is a Java development environment that is packaged with Tomcat. It 
is very easy to confi gure NetBeans to run web applications. There will be a discus-
sion of NetBeans in a later section in this chapter.
For other servlet engines, check the documentation to determine where web 
applications should be placed.
1.4.2 JSP
A 
Java Server Page
[JSP] contains HTML tags and plain text, just like a regular web 
page. In addition, a JSP can contain Java code that is executed when the page is 
displayed. As long as it is contained in a web application, a JSP will be able to 
process the form data that is sent to it.

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18
Web Development with Java
JSP Location
For now, the location of JSPs will be in the root directory of the web application, 
not in the WEB-INF directory. The WEB-INF directory is not accessible directly 
through a web browser. Later, you will see how it is possible to place a JSP inside 
the WEB-INF directory so that access to the JSP can be restricted.
Accessing Form Data
In the servlet specifi cation 2.0, there is a new language that has been added to JSPs 
that simplifi es access to objects that are available to a JSP. This language is known 
as the 
Expression Language
[EL]. EL statements start with a dollar sign and are 
surrounded by curly braces.
${EL-statement}
The EL statement for accessing data in the query string uses the word 
param
and 
the name of the form element that contained the data.
${param.name_of_element}
Consider the query string of 
hobby=water+skiing
. To retrieve the value of 
the hobby parameter from the query string, insert 
${param.hobby}
anywhere 
inside the JSP.
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