Mikaveli Mikaveli - 6 months ago 10
Java Question

Tomcat and Eclipse Zero Turnaround Deployment

I want to be able to deploy code changes to Tomcat (near instantly), while I'm developing in Eclipse.

So far, I have my output from Eclipse placing the built classes in the

WEB-INF/classes
folder of my web application.

I also have a reloadable context, with the
web.xml
as a watched resource. Any edit / save to this file does reload my web app, taking just over one second - much quicker than building a new war file and deploying it in full.

However, what I'd like to do is trigger the redeploy when I edit any source file. As the .class files are being modified in Tomcat, it seems I just need to monitor any changes in the
WEB-INF/classes
folder and it's children.

I've read that I can add additional watched resources in Tomcat's
context.xml
but this doesn't seem to be quite what I need - unless it's possible to specify a directory that will be watched (including recursively monitoring sub folders and files)?

<Context>
<WatchedResource>WEB-INF/web.xml</WatchedResource>
<WatchedResource>WEB-INF/someother.file</WatchedResource>
<Manager pathname=""/>
</Context>


So essentially, my question is can I watch the entire classes folder (without including each
WatchedResource
explicitly) to trigger a redeploy in Tomcat?

If not, can I configure Eclipse to
touch
the web.xml file, whenever I save a source file in that project? I'm developing on a Windows system. :(




PS I'm not interested in the JRebel product. Any answer should be a free solution.




Update

According to the Tomcat documentation, the classes folder should be monitored by setting the context to reloadable:


Set to true if you want Catalina to
monitor classes in /WEB-INF/classes/
and /WEB-INF/lib for changes, and
automatically reload the web
application if a change is detected.


Only changes to the web.xml seem to trigger a reload. Is this a bug or is my setup incorrect?

Also, I've read about setting the
docBase
attribute for a given context:

docBase="webapps/someExample"


This appears to be close to what I need, as I could then republish in Eclipse quickly. My only problem is that I require several web apps / servlets to be running in Tomcat concurrently, on the same port etc.

Answer

For these cases I set the eclipse build output to WEB-INF/classes as you have done and create a context file with the docBase set to the webapp folder (parent of WEB-INF) in the project. This is manually placed in conf/Catalina/localhost (assuming default configs for some elements of server.xml). End result is tomcat ends up serving from the development directory. So, change a servlet or other class and it is updated to the classes folder. Save a jsp and it is immediately available.

If project structured like:

src
|-main
  |-webapp
    |-images
    |-js
    |-WEB-INF
      |-jsp
      |-classes

Then context would be like:

<?xml version="1.0" encoding="UTF-8"?>
<Context path="/path" reloadable="true" 
    docBase="<pathtoproject>/src/main/webapp" />
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