apache commons lang3 stringutils taglib

Question

Id like to use StringUtils.abbreviate() inside a jstl tag, is there a taglib location for this?

Ive searched the commons site and the web but an unable to find an example. Is there a common way to find taglib locations also, maybe in a standard location of a javadoc tree??

Thanks! Nic

Rounder

Answer 1

Nic,

There often isn't a predefined tag to get at the apache util methods, but it's easy to add your own special tag definitions to point to the method you want. For example, add a local taglib definition to your web.xml file:

<jsp-config> 
    <taglib> 
        <taglib-uri>mytags</taglib-uri> 
        <taglib-location>/WEB-INF/jsp/mytaglib.tld</taglib-location> 
    </taglib> 
</jsp-config>

Your mytaglib.tld file will look something like this:

<?xml version="1.0" encoding="UTF-8"?>
<taglib version="2.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <tlib-version>1.0</tlib-version>
    <function>
        <description>Exposes the abbreviate() function from Apache StringUtils</description>
        <name>abbreviate</name>
        <function-class>org.apache.commons.lang.StringUtils</function-class>
        <function-signature>java.lang.String abbreviate(java.lang.String,
                            int)</function-signature>
    </function>
</taglib>

In your JSP, you can then use your new custom tag:

<%@ taglib prefix="mytags" uri="mytags" %>
...
<c:out value="${mytags:abbreviate(myString, 5)"/>

That should do it for you. For more info on custom tags, you can read here: http://docs.oracle.com/javaee/5/tutorial/doc/bnalj.html

Templeton

Answer 2

I wrote one for commons-lang 2.4.

https://github.com/hussachai/commons-lang-taglibs

You can use it as a template for 3.0 by the way.

Charge

Answer 3

I was initially thinking of going with a custom taglib also. Thanks for the post, it gave me this idea. Creating an instance of StringUtils worked just fine on it's own. Even though the calls are static. I suppose you could wrap it into a two-liner tag if you wanted to.

The example below will output the following: Now is the t...

<%@ tag import="org.apache.commons.lang3.StringUtils" %>
<jsp:useBean id="StringUtils" class="org.apache.commons.lang3.StringUtils" />
<c:out value="${StringUtils.abbreviate('Now is the time for all good', 8) }" />

Note that the tag import statement seems to be optional. The above code works for me with or without it.

Chromosphere

It even works inside Jelly scripts without importing, if using "org.apache.commons.lang.StringUtils". Thanks! – Squad