How to add TLD and Tag Lib files into a Maven's jar project

Question

I have a Maven project that is packaged as jar.

And I also have a Maven project that is packaged as war. This war project has a tld file and some xhtml files (the tag libs). The structure of the war project is (basically):

pom.xml
src
    main
       java
           ...
       webapp
           WEB-INF
               my-facelets.taglib.xml
               facelets
                   aTag.xhtml
                   anotherTag.xhtml
           META-INF
               my-facelets.taglib.tld

And then appeared a requirement to remove those xml, xhtml and tld files from the war project and package them into the jar project. So my first try was add in the jar project's POM:

<resources>
  <resource>
    <directory>src/main/tld</directory>
    <targetPath>META-INF</targetPath>
  </resource>

  <resource>
    <directory>src/main/taglib</directory>
    <targetPath>WEB-INF</targetPath>
  </resource>
</resources> 

And put the files, of course, into src/main/tld (the ones I wanted to export into META-INF) and src/main/taglib (the ones I wanted to export into WEB-INF). And the jar was created as I wish:

myjar
    com
        my
            classes
    WEB-INF

    META-INF
        my-facelets.taglib.tld
    WEB-INF
        ...

And then I added this new jar to my first war project, as a maven dependency.

The problem is that those .tld, .xhtml, .xml files that are inside the jar's META-INF, WEB-INF (the jar is inside war's WEB-INF/lib) are not recognized. Apparently they should be directly into the war structure, unless some other configuration is performed. This is a must-have requirement, because multiple war projects will use the features (classes and taglibs) of the jar project.

Solution 1

The practice these days is to put the TLD files into the tag library JAR and let the class loader find them. Download the Apache JSTL JARs and see how they do it. I'd recommend following that convention. It'll simplify your app too, because you won't have to declare the TLD in your web.xml file: just put the JAR in your CLASSPATH and make sure that the URI in your .jsp matches that in the TLD.

Solution 2

@duffymo - Your solution totally works. Adding graphic to your description.

Create a maven project that generates JAR. keep the structure like this below

 src -- main
            |-- java
            |      `-- net
            |            `-- madhur
            |                 `-- helloTag.java
            `-- resources
                  `-- META-INF
                        `-- tags
                             `-- customTags.tld

To your customTags.tld file add uri something like this

<uri>http://www.xyzabc.com/taglibs/customTags</uri>

Accessing tags in you WAR file

War should have following structure

  META-INF/
  META-INF/MANIFEST.MF
  WEB-INF/
  WEB-INF/classes/
  WEB-INF/lib/
  WEB-INF/lib/{tagLibrary}.jar
  WEB-INF/web.xml
  WEB-INF/customTags.tld

web.xml

    <jsp-config>
        <taglib>
            <taglib-uri>www.xyzabc.com/taglibs/customTags</taglib-uri>
            <taglib-location>/WEB-INF/customTags.tld</taglib-location>
        </taglib>
    </jsp-config>

Using tag in FTL or JSP file

Ftl:

<#assign ct = JspTaglibs["www.xyzabc.com/taglibs/customTags"]>

Comments

[bluefoot]

I was thinking too of downloading something an see how they do. I'll check it out and post the results.

[bluefoot]

it works correctly. No need to declare anything into Manifests. Just inserting all the files inside jar's META-INF and letting maven build the war (with the jar inside it's WEB-INF/lib) did the trick. The error was the <targetPath> of my second <resource> element.