How can i avoid restarting tomcat server when servlet is modified?

Question

please advice me that how can i avoid restarting the tomcat server, whenever a servlet file is modified in my application. is their any way ?

Answer 1

No probs. Here's how I do things...
1. Install tomcat as normal (e.g. I install to C:\Apps\jakarta-tomcat-5.5.4)
2. Create a webapps directory in your eclipse project with the following directory structure
MyEclipseProject
   - src
   - conf
   - webapps
      - MyApplication
         - META-INF
         - WEB-INF
            - classes
            - lib
            - pages3. Set the project's output folder (e.g. bin folder) to webapps/MyApplication/WEB-INF/classes
4. Put all your jar files in the lib directory
5. Put JSPs / HTML in the pages directory (you may also want to create additional directories for TLDs, config files etc)
6. Ensure your web.xml is in the WEB-INF directory
7. Although it isn't essential I create a context.xml file and store it in META-INF, e.g.
<Context reloadable="true">
    <!-- Default set of monitored resources -->
     <WatchedResource>WEB-INF/web.xml</WatchedResource>
     <WatchedResource>WEB-INF/conf/struts/struts-config.xml</WatchedResource>
     <WatchedResource>WEB-INF/conf/struts/tiles-defs.xml</WatchedResource>
     <WatchedResource>WEB-INF/conf/struts/validation.xml</WatchedResource>     
</Context>I use this to set monitored resources that will trigger an automatic appliation reload and to configure JAAS (not shown). See the Tomcat documentation for additional information.
8. In the 'conf' directory I create a server.xml file used to configure Tomcat (you can copy the one from your <TOMCAT_HOME>/conf/server.xml).
After copying the file change appBase attribute in the host element to be the full path to the webapps directory. You can also change the HTTP and HTTPS ports if you wish
9. Download and install the Tomcat Launcher plugin from Sysdeo.
10. In Eclipse's Preferences menu you will see a new entry for Tomcat. Click this then
a. Set your Tomcat Version
b. Set your Tomcat Home
c. Set "Context declaration mode" to server.xml
d. Set the configuration file to the full path to your server.xml file created in step 8
On the "Advanced " sub page select all relevant projects to add to the Tomcat classpath
On the "JVM Settings" page add all the jars in your WEB-INF lib directory to the class path
On the "Source Path" page select all relevant projects
Now if you start Tomcat using the Tomcat icon, you will be able to remote debug your application. If you change web.xml (or any other file in your context.xml watched resources) it will automatically reload. Any changes to JSPs will automatically be picked up (providing your tell your browser not to use the page in cache - e.g. CTRL+F5 in IE)
There are some limitations that I'm still working on however. Primarily that I haven't included the Tomcat Manager application in my webapps directory, so Sysdeo cannot perform a reload. This means that if I change a source file, and eclipse auotmatically rebuilds, Tomcat doesn't pick up the change unless I either change a watched resource file (e.g. web.xml) or stop and restart Tomcat.
There's no reason why this can't be fixed, I just haven't got round to it yet.
I'm sure there are lots of other (probably better) ways of achieving the same thing. This was the first method I tried and it worked, so I stuck with it. I'm not a Tomcat config guru and I'm sure other forum users could provide some improvements should they wish.
Post if you get into trouble, however I won't be able to respond until next week.
Cheers,
Steve