How do I properly deploy and structure projects in Eclipse against Tomcat?_问答_开发者

I am relatively new Java developer that's been thrown in the deep end, my usual skillset lies in Microsoft products and C#.

However I have managed to write a nice web service using Restlet and incorporating Toplink and doing some database CRUD stuff, etc etc.

I developed this in Eclipse against Tomcat 5.5. I followed tutorials and examples and managed to throw something together that works.

I had all my jar files in WebContent/WEB-INF/lib directory of my project - I soon realised that when I export this as a WAR file and deploy in Tomcat, it takes these jar files with it and stores them local to the application.

Fine, but then when you try to undeploy the app, it only does it partially as Tomcat "holds on" to some of the jars it was using i.e. the Oracle JDBC, and Toplink ones. This makes sense as the web service was using these jars as there was a live Oracle connnection going on.

So then I thought I should have all these jars in a common place where all deployed apps can access them, that folder I believe is:

C:\Program Files\Apache Software Foundation\Tomcat 5.5\common\lib

(in my case). This made total sense, it's logical as you don't want loads of apps on Tomcat all referencing the same jars. So I removed all the jars out of 开发者_C百科my projects lib folder and put them in the common\lib directory.

Now my app will not work properly - it can't find my source code in src, the custom bespoke code that I have programmed against these jars. It will only work if I jar up my source code and put in the directory stated above. Odd.

I am obviously very confused with class paths and build paths and all of that stuff, and must have got this sort of stuff all wrong as I am no Java expert, as I readily admit I have pretty much hacked this together - so can anyone explain to me in laymans terms how I should structure my project to get it working with jars held in a common folder in Tomcat. Or are there any good resoureces on the web to help explain to me what I should do.

Hope this all makes sense...

Here is a pic of my current project:

How do I properly deploy and structure projects in Eclipse against Tomcat?

Sounds like you are not using WTP web project.

If you've installed 'Eclipse IDE for Java EE Developers' flavor of Eclipse, the WTP is already bundled in there. Otherwise here its update site -> http://download.eclipse.org/webtools/updates

Once you've installed WTP you should create 'Dynamic Web Project'. In general I would recomment to put only your presentation layer here ( JSPs, CSS, HTML ) and put all pure java projects into standard 'Java' project that you later add as a dependency to 'Dynamic Web Project'.

WTP can run your web application under a number of containers, fortunately Tomcat is supported. You will need to configure it through Window->Preferences->Server->Runtime Environments.

Once runtime envirnonment is configured, you can create your server runtime:

Right click in 'Servers' view.
Choose New->Server
Select server type: 'Tomcat v.5.5 Server'
(Optional) Change server name to whatever makes sense for you
Select server runtime environment: This is the Runtime Environemtn that you have configured previously
Hit 'Next' button
Add your 'Dynamic Web Project' project to 'Configured projects:' panel
Hit 'Finish' button

After the server is configured you can just run it, or you can put it in Debug mode. All source code referenced by dependent projects will be available for debugging.

NOTE: From personal experience, I would not recommend using common/lib. Put all the jars that your web application relies upon into its WAR file. If you are worried about dependency tracking then start looking into Maven and m2eclipse.

Usually I put my jars in $CATALINA_BASE/shared/lib/
Please read this documentation for more clarification and specially Class Loader Definitions section.
Also restart the server after you copied the jars.

Go to Window > Show View > Other > Server > Servers, a servers tab will appear below with console tab. Click on your server and then F3, this will open server configuration.
Check Server Locations, and make sure you checked Use tomcat installation(takes control of tomcat installation) then click Modules tab below and it will show your installed modules, make sure the module is present or add it.