JavaServer Pages, 3rd Edition

Packaging Tag Files for Easy Reuse

All examples in this chapter use a taglib directive with a tagdir attribute to specify the directory that contains the tag files. While this is handy for custom actions implemented as tag files in an application you control, it’s not as easy as one would want for deployment and use of the tag library in third-party applications. As you may recall from Chapter 7, it’s very easy to deploy a tag library packaged as a JAR file; just put the JAR file in the WEB-INF/lib directory and use the default URI as the uri attribute value in the taglib directive.

You can do the same with a tag library developed as tag files, but in this case you must also create a Tag Library Descriptor (TLD) and include it in the JAR file. I described the purpose of the TLD briefly in Chapter 7, but let’s take a closer look at it here. Example 11-8 shows the TLD for a tag library with some of the tag files we’ve developed in this chapter.

Example 11-8. TLD for tag files

<?xml version="1.0" encoding="ISO-8859-1" ?>
<taglib xmlns="http://java.sun.com/xml/ns/j2ee"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
    http://java.sun.com/xml/ns/j2ee/web-jsptaglibrary_2_0.xsd"
  version="2.0">

  <tlib-version>1.0</tlib-version> <short-name>my</short-name> <uri>mytaglib</uri> <tag-file> <name>copyright</name> <path>/META-INF/tags/mytags/copyright.tag</path> </tag-file> <tag-file> <name>forEvenAndOdd</name> <path>/META-INF/tags/mytags/forEvenAndOdd.tag</path> ...