Category Archives: Struts

Apache Struts is a free open-source framework for creating Java web applications.

mod_rewrite to bypass security

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Many Apache webserver installations use uriworkermap to configure requests are forwarded to Tomcat/JBoss and which are not.   This provides a certain level of security.  For example:

## APACHE RESOURCES (static files):
!/*.gif=myapp
!/*.html=myapp

## DISALLOW  (security-related filter):
!/*.jsp=myapp
!/*.xml=myapp

## TOMCAT RESOURCES:
/*.do=myapp

However if you dynamically generate your sitemap.xml or any other XML files using a servlet then this security will be a problem since the XML request will not make it to Tomcat/JBoss.  This is when mod_rewrite comes to the rescue.

You can set up mod_rewrite to rewrite the sitemap.xml request to be a sitemap.do request.

RewriteRule ^/sitemap\.xml$ /sitemap.do [PT,L]

Then you can set up Struts to forward this request to sitemap.xml.

<action path="/sitemap" forward="/sitemap.xml"/>

Size of collection in a JSP/DSP page

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leaf pile on Flickr

(Photo: leaf pile by oeimah)

Sometimes in a JSP/DSP page you will want to get the size of a collection and unless you are within a Range, ForEach or similar droplet you won’t have access to this value.

Struts has a nice solution using the bean:size tag.  JSTL 1.1 has a nice solution using the fn:length function.

Here is an example of how to use Struts, DSPEL and JSTL to get the size of a collection.

  <dspel:getvalueof param="book.pages" var="pages"
                    vartype="java.util.Collection"/>
  <bean:size id="numPages" name="pages"/>
  Number of Pages: <c:out value="${numPages}"/>
  Number of Pages: <dspel:valueof value="${numPages}"/>

Here is an example of how to use JSTL 1.1 and DSPEL to get the size of a collection.

 

  <dspel:getvalueof param="book.pages" var="pages"
                    vartype="java.util.Collection"/>
  Number of Pages: <c:out value="${fn:length(pages)}"/>

Submitting a form with a radio button

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Submitting a form from a radio button is not common but it is a nice UI which is even better when done with AJAX.

A typical form with two radio buttons would look something like this.

<form action="test.html">
1 <input type="radio" name="test" value ="1"><br>
2 <input type="radio" name="test" value ="2">
<p><input type="submit" value="submit">
</form>
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2

But with basic JavaScript you can make a simpler form like this.

<script>
function submitAction( form, absPath ) {
form.action = absPath;
form.submit();
}
</script>
<form action="test.html" id="test">
1 <input type="radio" name="test" value ="1" onchange="submitAction(document.getElementById('test'), 'test.html')"><br>
2 <input type="radio" name="test" value ="2" onchange="submitAction(document.getElementById('test'), 'test.html')">
</form>
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2

If you are using Struts the above form’s JSP would be:

<html:form action="test.do" styleId="test">
1 <input type="radio" name="test" value ="1" onchange="submitAction(document.getElementById('test'), 'test.do')"><br>
2 <input type="radio" name="test" value ="2" onchange="submitAction(document.getElementById('test'), 'test.do')">
</html:form>