JSP Copyright tag file example

This is a simple example in .tag files, the concepts can apply to many other uses.

I’ve chosen the following common usage example:

Websites often need to contain copyright date and information in their footer.

Add this to your existing JSP page (or JSPF fragment):


<%@ taglib prefix="webinf" tagdir="/WEB-INF/tags" %>
<webinf:copyrightyear />

Create the .tag file – /WEB-INF/tags/copyrightyear.tag


<%@ tag language="java" isELIgnored="true" trimDirectiveWhitespaces="true" description="dynamically calculates year" %>
&#169;<jsp:expression>java.util.Calendar.getInstance().get(java.util.Calendar.YEAR)</jsp:expression>&#160;<jsp:doBody />

NOTE: I’ve used the <jsp:doBody /> inside the tag file in this example, as such you can also use the following format on your page(s) to use the content between the open and close.


<webinf:copyrightyear>Example</webinf:copyrightyear>

NOTE: if your server supports it, you can also use XML formatted tag file with:

<jsp:directive.tag language="java" isELIgnored="true" trimDirectiveWhitespaces="true" description="dynamically calculates year" />

Internationalizing JSP with ResourceBundles

Adding multi-language support to JSP based applications is very simple. In this post we will investigate the method that you can use to externalize your text based content.

NOTE: Additional work is required to establish the Locale, format Dates and Numbers or to support other differences such as text-direction.

JSP:

<%@ taglib prefix="fmt" uri="http://java.sun.com/jsp/jstl/fmt" %>
<fmt:setLocale value="en_US" />
<fmt:setBundle basename="ResourceBundles.TestBundle" scope="request" var="rb" />
<fmt:message bundle="${rb}" key="label.test" />

/src/ResourceBundles/TestBundle.properties:

label.test=test(default)

/src/ResourceBundles/TestBundle_en.properties

label.test=test(en)

/src/ResourceBundles/TestBundle_en_US.properties

label.test=test(en_US)

You can also specify some default Locale information in web.xml if you do not wish to use the in your JSPs.

/WEB-INF/web.xml


<context-param>
<param-name>javax.servlet.jsp.jstl.fmt.locale</param-name>
<param-value>en</param-value>
</context-param>

<context-param>
<param-name>javax.servlet.jsp.jstl.fmt.fallbackLocale</param-name>
<param-value>en</param-value>
</context-param>

Some explanation… in this case we’ve told our JSP that the resources are in the TestBundle properties. As the Locale is set to ‘en_US’ it will first look in the TestBundle_en_US.properties file, if not found it will then look in TestBundle_en.properties and finally in TestBundle.properties. If not found there, the output will generally be in the form ‘???key???‘, in this example: ‘???label.test???‘, my understanding is that this can be suppressed by setting ‘allowNull=true‘ somewhere, but I have never found that setting to date.

REFERENCES:

XML formatted JSP source code

I’ve found that many developers still use the classic coding style on JSP’s, unfortunately this makes it difficult to use some common tools for validation and complicates matters when looking for improperly nested tags in the markup. Migrating the XML formatted JSP markup simplifies matters and makes it possible for developers to quickly identify many problem areas of code within the IDE.

<%@ page language="java" %> = <jsp:page.directive language="java" />

<%@ page contentType="text/html; charset=utf-8" %> = <jsp:page.directive contentType="text/html; charset=utf-8" />

<%@ page import="" %> = <jsp:page.directive import="" />

NOTE: you can combine page.directive’s to a single tag with all attributes.

<% //some scriptlet %> = <jsp:scriptlet>//some scriptlet</jsp:scriptlet>

<%! String somevalue="1"; %> = <jsp:declaration>String somevalue="1";</jsp:declaration>

<%= somevalue %> = <jsp:expression>somevalue</jsp:expression>

<jsp:include page="" />
<jsp:directive.include file="" />

<jsp:useBean id="" scope="" type="" />

<jsp:setProperty name="" />

Unfortunately, there’s one common type of tag that does not have an XML equivalent:

<%@ taglib prefix="c" uri="/WEB-INF/tlds/c.tld" %>

REFERENCES:

Happy coding