I earlier got to create a simple RESTful webservice on my localhost using Eclipse IDE, Tomcat, and JAX-RS libraries.
I am now trying to move the same on to a different unix server which has Tomcat installed. I am not knowing how to get started as in what is equivalent to creating a "Dynamic Web Project" that I do in Eclipse. Do I need to just create a directory myself with all the sub-directories as created by Eclipse? Should this directory be placed in webapps folder in Tomcat container. Should META-INF and WEB-INF also be created by myself?
Where should I put my Java classes?
Can somebody please clarify this or direct me to any documentation about the same.
You need to package your application in a WAR file.
The Sun Java EE 6 Tutorial has a chapter deciated to packaging.
It's pretty easy to export a web application as a war in Eclipse.
Dynamic Web Project (right click) => Export => Web =>war file =>war export dialog
Creation of web application archive - WAR is the solution for your problem,
but take care about all libraries that you need there.
You can easily extract (unzip) WAR file content
and check your project structure and libraries needed
and they will be in WAR's WEB-INF/lib.
Make sure that both Tomcats are set same way,
make sure your code is all OS friendly (users, file paths, permissions)
Always write some test simple code that will run up on app start,
and check all dependencies and libs, system clock, outside world network communication, so you can trace it in web app console or logger easily.
regards
Related
I am unable to find another article that solves my problem but am happy to hear about one if you know the answer.
I have a RESTful service built in Java with Eclipse. It uses Spring and all of its bells and whistles.
After much work with configuration files, I am able to build the service into a war file, deploy it to my Tomcat webapps folder, and run it from standalone Tomcat. However, it still throws several errors on start when I try to start it from a service defined within Eclipse. The errors are the same errors that I was seeing before I got the config files correct for standalone Tomcat. The errors are about the inability to create the required beans because of references to properties that can't be found.
How did I get it running in Tomcat? I added a couple of .properties files to define properties needed by the beans that get launched at startup and then added a 'set CLASSPATH=...' line to the setenv.bat file in the Tomcat bin folder. This new line adds the properties files into the CLASSPATH. That seems to have fixed everything from standalone Tomcat.
So, my question is, "How do I make these same changes inside my Eclipse server?" I have added the properties folder with the property files under the config folder in Eclipse, just like it is in my native Tomcat folders, but I do not know how to modify the CLASSPATH string to specifically point to my .properties files (as I have done in the setenv.bat file for standalone Tomcat).
I think I understand the problem, but have no idea about the solution.
Thanks for listening.
Dave
Eclipse does not use any *.sh/*.bat files to startup Tomcat. In order to modify the way the server is started you have to open the configuration UI of the server by double-clicking on the server in the Servers view.
From there you will be able to modify the classpath of the system classloader through "Open launch configuration".
Another important setting is "Server path" which tells Eclipse, the value of $CATALINA_BASE. You can modify it only after removing all modules and cleaning the server. It is useful to set it to an easily accessible directory: this way you can verify directly that Eclipse didn't mess up your application deployment (sometimes it "forgets" to copy some libraries).
The "Configuration path" setting tells Eclipse where to find the files (but not subdirectories) that will be copied into $CATALINA_BASE/conf.
Remark: if your application requires you to add libraries to the top classloader, there is probably a problem in your project. The "missing" libraries should be added to WEB-INF/lib of your application instead: look into the "Deployment assembly" of your Eclipse project configuration.
Can anyone tell me..while running servlets iam using apache tomcat. But everytime i make changes to my web application..I have to export the war file and put into the webapp directory again and again..it is too much time consuming and very hectic. For even small changes i have to export war file and then put in my webapp directory. I cant run my web application without doing this..i mean new changes are not reflected till then..
Isn't there any other method..i think auto deploy should do..and however it is set to true in my web application. but it is not doing it..I have been searching on the net since 2 days..but didn't got any solution..please help..
A WAR file is basically just a .zip with the respective webapp contents. Instead of deploying a WAR, you can deploy an "exploded WAR", being the contents of your webapp. Various build tools support doing this, for example, Maven supports the dir packaging in the assembly plugin. Then, you can for example configure your project to build classes directly to your WEB-INF/classes directory of your "exploded WAR".
EDIT: In case it wasn't clear - you just put the exploded WAR within a directory in the webapps directory where you normally put the WARs - so instead of application.war, you just put an application directory containing the webapp.
Most popular IDEs like Eclipse, IntelliJ or Netbeans provide web testing and publishing tools for users, it's a very basic feature.
In case you're using Eclipse, navigating to Web Tools Platform User Guide > Using the server tools in help page, should be sufficient for you to set up the environment.
Here's online help document for Eclipse Mars, for your convenience.
IDE
You can develop with IDEs like Eclipse or Netbeans. It will be easy to develop and auto-deploy will be taken care by themselves. It will save much time. And completely developed final product can be exported at final stage.
As mentioned, the IDEs nowadays can do some rapid redeployment or hot-swapping of classes. This can work for some scenarios but not all.
JRebel
For even more advanced hot-swapping in more scenarios, consider the commercial tool JRebel by ZeroTurnAround.com.
We currently have an Java application that can be deployed on clients or run as a shortcut from the server. We have intermittently received ClassNotFound exceptions when running the JAR from the server which looks like Windows dropping the network connection with only part of the classes from the JAR loaded (user opens a different screen then the problem is apparent).
I am currently looking at the Web Start technology to allow us to run a single shortcut.
However the application has several folders it requires to be in the same folder the JAR is launched (for configuration, logs, etc.). These folders will require full access for all users to allow them to write log files. There are lots of configuration files under the configuration folder hierarchy.
The application also requires access to environment user settings (such as getting their user folder). It also requires certain command line parameters (including which folder to use for configuration, log file location, java memory usage, etc.)
Edit
The application also contains a reference to 2 signed JARs. These are:
jh.jar
mail.jar
It looks like these are signed by SUN Microsystems. jh is used for help integration in our application whilst mail is used for email integration.
I have now downloaded the latest versions of these files from java2s.com which do not have the signed equivalents.
end edit
The application is developed in Netbeans which compiles a single JAR file and copies the dependant JARs to the dist/lib folder. I enabled the Web Start functionality in Netbeans for the application and it generates the JNLP file.
Bearing everything in mind is Web Start the way to go for an application like this?
Can you include folders in a Web Start deployment? I could not find anything to do this in the XML structure for a JNLP file.
Cheers,
Andez
Yes, you could use WebStart for this.
Permission:
If you need permission to the file system, you have to sign your jars and put the all-permissions tag in your jnlp.
Arguments:
Arguments can be provided by using the arguments elements in application_desc.
Folders:
I'm don't think you can include folders in the WebStart application, but you could put the config files in a jar and read them from there, or extract them on startup.
ClassNotFoundError:
We have intermittently received
ClassNotFound exceptions when running
the JAR from the server which looks
like Windows dropping the network
connection with only part of the
classes from the JAR loaded
Does not sound plausible to me. per default, all jars will be downloaded before the application starts. If you set "download" to "lazy", the jar will be downloaded when first needed, but I would guess it will be downloaded completly then.
You can provide read-only resources for Java WebStart. Getting the log back is harder. I would suggest looking into a centralized logging solution, using one of the standard appenders in the log framework you use.
For a Java Web Start application it is always advised not to create files or folders in the class path. Recommend user's home directory to store your settings or database files.
I come from an Asp.Net development background and am very comfortable there. I was asked to support an existing Java Web Application w/ struts and am able to figure most of it out with my Asp.Net knowledge and my android development experience. However, I'm having a really simple but stupid problem.
All i have is the website as it exists on the server, no source project to work from. The folder on the server contains both .java and .class files, but the folder doesn't just import into netbeans as a recognized project.
What's the easiest way to get the site imported into some sort of IDE (I can work w/ eclipse too if netbeans isn't recommended), and get it to compile so I can deploy some updates.
It will not be easy to answer fully to your question here. But we should be able to achieve that by steps :)
Here i will speak for eclipse. But it is only because i'm not familiar with netbeans.
First of all create a clean "dynamic web project" under eclipse (using a J2EE enabled eclipse http://www.eclipse.org/downloads/).
Then :
copy your sources files in "Java Resources"
copy the rest of your application (without the class files) in WebContent
In order to test your application localy you will need a local server. Tomcat can be integrated easily in eclipse.
Usually you shouldn't have to (re)construct a project from a deployed web-app; the project should have been kept in version control. Source code isn't usually deployed to the server, either, but if it's been done in this case, you're in luck.
I would just make a new web project in NetBeans and manually move the .java files into it, along with the other resources (except for the .class files).
If you can use eclipse, and the source files are already in the war file as you say. You can import the war file directly into eclipse as project.
file -> import -> war file or existing project into workspce or filesystem (Several other options exists)
I have installed and configured tomcat+solr on my personal linux machine and windows as well. I was able to get them working fine. I'm very new to Java and how the file structure works. (i.e. knowing where to put war files and what WEB-INF is) So now that I am ready to install solr and configure it on my clients shared hosting plan, the directions are different from what I did before. I dont want to mess this up and apparently the webserver reboots daily and I dont think I can do it manually which means I have one shot at this every day.
Here is the directions for installing a tomcat servlet on his hosting provider:
http://www.apluskb.com/scripts/Where_do_I_put_my_answer1186.html
As you can see I need to install solr under the html/WEB-INF directory, but read what it says.. its very confusing:
"All Servlets should be uploaded in the /html/WEB-INF/classes directory. Any unpacked custom classes and resources should be uploaded in the /html/WEB-INF/classes directory, while classes and resources packed in Jar files should be uploaded to /html/WEB-INF/lib."
uhh... so which is it? /classes? or /lib? I dont think they explain that very well and I'm a little confused by this statement. Also what exactly do I install? With a normal solr install, solr is put somewhere else, the war file is copied into tomcat and the rest of solr is referenced using some kind of XML configuration file.
Also, since I'm a little new to Java and servlets, can someone explain the tomcat file structure to me (in great detail will definitely get you a +1 from me) and where things should go and why?
Thanks in advance!
Web application structure is defined by J2EE spec, it's not limited (or specific) to Tomcat per se. Here is a detailed tutorial covering its layout. Briefly, however, it's as follows:
There a base (root, home, whatever you want to call it) folder which serves as root of web application, everything else goes under it.
All public stuff (html, images, CSS, javascript, JSP, what have you) goes under that folder (directly or via subfolders).
There's one special folder, also located directly under root, called WEB-INF. It contains non-public stuff, like application descriptor (web.xml), classes (which go into WEB-INF/classes folder), libraries (WEB-INF/lib) and possibly configuration files.
Application can be deployed either using expanded structure above or as WAR (web archive) which is basically an archive containing everything above starting at root folder level (but not including root).
The distinction between classes and lib folders is simple: all packaged libraries (JAR files) need to go into lib; all unpackaged classes (and resource files that need to be in classpath) have to go into classes preserving their directory structure (e.g. com.mypackage.Blah class should go into classes/com/mypackage/)
In your case, it looks like you can only have one web application deployed and it has to be deployed to /html folder. If you're deploying a war file, you need to extract it to that directory (e.g. from within that /html folder run jar xvf solr.war or whatever it's called).