Java Reference
In-Depth Information
T
ABLE
19.1
Continued
Subelement
Definition
The type of content that is in the body of the tag:
JSP
,
empty
,or
tagdependent
bodycontent
optional
tag-specific information
info
Names an attribute or attributes to be passed to the tag handler
attribute
Each of the subelements mentioned in Table 19.1 will be further defined as we cover the actual
development of some custom tags.
Deploying the Tag Handlers to Your Web Application
The tag handlers are the actual code that is executed when a named tag is encountered in your
JSP. The tag handlers that we will define in a later section will be compiled into class files and
deployed to the Web application.
Tag handlers can be deployed in two ways. The first is just as straight class files with a
tld
defining all of the tags and their handlers in the library. You would do this by moving the class
files into the Web application's class path. When deploying to Tomcat, using our
djs
Web
application, you would move the class files into the
<SERVER_ROOT>/webapps/djs/
WEB-INF/classes
directory. The
tld
would then need to be moved into a directory, preferably
in the Web application space that will be referenced in the
web.xml
.
The second way to deploy a group of tag handlers is in a jar file. When you choose this route
you need to compile your tag handlers and jar them with their
tld
. The
tld
will need to be
added to the jar file at the top level in the
/META-INF
directory. The
tld
will also need to be
stored in a file named
taglib.tld
. You should then move this jar file into the classpath of the
Web application; using our
djs
Web application, a common location would be in the
<
SERVER_ROOT>/webapps/djs/WEB-INF/lib
directory.
Adding a
taglib
Entry to Your Web Application
After you have created your
tld
and deployed your tag handlers, you need to deploy the
library to your Web application. If you choose to deploy your tag library as straight class files,
you will need to directly name your
tld
in the Web application's
web.xml
file. An example of
this is in the following code snippet:
<taglib>
<taglib-uri>/djs</taglib-uri>
<taglib-location> /WEB-INF/tlds/taglib.tld</taglib-location>
</taglib>
