Sorry, I'm very new to java servlets. I have an existing java package (that I built and ran in eclipse, did not compile) that runs fine on its own. I have a sample servlet in another folder. I'd like to compile all of this so it can run on a tomcat server. I know a javac will compile a class, but which one do I compile if this is a servlet AND another package? Do I have to list ALL classes, can I list just the package names? Do I need to create a single .war file or multiple .war/.jar files?
Sorry, my use of Java up to now has been in Eclipse. I can compile and run a single class, but a complex environment with multiple packages with a target platform of tomcat is leaving me lost as to 'where I begin.
You can do following:
1) First project should be able to create a jar file.
2) In the Second project ( Servlet) ,you can right click on the folder of the dynamic web project( I assume you have created it as DWP) , and click Properties --> Deployment assembly. Here you can add reference to other projects and external jars.
3) Once you are able to do this setup, you can try 'exporting' your second project as war.
This is just a naive way to start as I do not want you to overwhelm with complexity of multi module development for a beginner. But will point you to m2e plugin in eclipse for something called "Dependency Management" . This plugin will help you manage much more bigger and complex projects. Do spend some time on http://www.mkyong.com/maven/how-to-create-a-web-application-project-with-maven/ to understand maven and how to it works before attempting Maven in eclipse with m2e plugin.
Related
For example I have a regular Java project and multiple EAR projects JSF + EJB inside EAR. Each EAR project has as a dependency, my Java project, for example it might be a library of composite JSF components.
Is it possible to define that when I exporting an EAR project it will compile depended Java project into jar and put it as a library inside EAR\libs?
Same thing regarding committing project via RTC, now I need manually build jar and add it to my EAR project, is it possible to do it automatically?
RTC wouldn't provide any additional compilation feature compared to the platform (Eclipse) it is installed on.
It does provide however RTC Builds, and you could use that task scheduler to, on demand, trigger the compilation of the Java project and its import into the ear/libs.
That supposes first that you can do those tasks in a script (using any scripting technique you want: ant, maven shell, bash, anything).
Then you can define a build definition using that script.
I need to do a Java web project. I'm going to be using Eclipse.
I thought of using Spring MVC. As far as I can tell - it's gonna require me to add some "extra" stuff to a "clean" Java web project. I don't mind that - the thing is - one of the project requirements is - that I'll be able to send the project to someone else - that doesn't have any extra installation and/or configuration - and he will be able to compile the project.
Is that possible with Spring MVC? Does the Spring MVC framework is just a "JAR" like addition to the project - therefore - the project can be shared without a problem?
Thanks.
Short answer: yes, you are right.
To use Spring in your Java web project, you generally need to add two things:
the appropriate Spring configuration file(s) (XML)
the appropriate Spring JAR files (traditionally placed in /WEB-INF/lib, the same as other JARs). By the way, it is NOT a single JAR file, but several JAR files.
That is all there is to it.
Spring has nothing to do with "sharing the project".
To "share" the project with someone else, you put it on the SCM of your choice and your collaborators will be able to get the code and work on it.
Building the project is a different aspect. To correctly compile the project you have to make sure that all the classes and/or jars are visible in the classpath (and runtime if you want to execute the code). Spring is made of a bunch of jars that, depending on which classes of the framework you use, must be in the classpath (eg. putting them in the /WEB-INF/lib directory). You may version them as well, or just version the configuration (I'm thinking about Maven for example, that will take care of resolving the dependencies).
Another piece of the puzzle is making all of this work in your IDE. This is a matter of taste. I prefer not to version ide-specific files (in the case of Eclipse, .settings and .project files/folders). You can do that, making sure you do not use absolute path anywhere, and technically you will be able to import the project without problems from another machine.
Yes.
If the other person has nothing extra installed and configured, namely no build tool, you need to put every needed Spring and other Jar into a folder, typically called "lib" and tell him to add them into his compile process. If he just uses the JDK he will get an enormous command line. It is much better to use a build tool like Maven or Ant+Ivy for building and dependency resolution. But that would be an "extra installation" per your question.
If he has Eclipse installed like you have and you use Eclipse internal for building:
Put the JARs in a lib folder
Configure the build path
Make a local test build
Export the project as zip (File menu > Export)
" The other person needs to import the project into his workspace
The exported project should not have any absolute paths as long as you didn't set some deliberately in the build path.
This works but is not exactly best practice. Installing a build tool like Maven is absolutely worth the time and should be preferred under any circumstances. It will save you a lot of time and nerves.
I'm working with some very old, monolithic software that is basically a heavily customized JBoss deployment. Unfortunately, this means that JBoss can't be started from the "Servers" view in Eclipse, it must be started as a Windows service or via the command line. There are multiple WARs/EARs, but the WAR classloaders are rarely used and most of the actual class files are located in jboss/shared/lib as .jars.
We need a way to run a Maven build in Eclipse (via m2e) and deploy the class files in the resulting .jar to C:/product/jboss/shared/lib so that when we start JBoss, we can use Eclipse to debug (as a remote java application). Ideally, the artifact that Maven pushes will not overwrite the existing .jar file that was originally installed. For example, if the Maven project builds an artifact named myjar-1.0.0.jar, we need a way to deploy the classes inside of myjar-1.0.0.jar to C:/product/jboss/shared/lib/classes so that they are picked up by the classloader prior to C:/product/jboss/shared/lib/myjar-1.0.0.jar, which was installed with the product.
Currently, our (very hacky) solution is this:
Under the project configuration's Java Build Path > Source tab, we use the "symlink" functionality under Advanced to map the Default Output Directory (e.g. project/target/classes) to a class folder (e.g. C:/product/jboss/shared/lib/classFolder). This modifies the .project file, which is checked into source control.
We build the project normally with a m2e launcher (e.g. clean install).
Assuming the Maven build is successful, we run an Eclipse project build. This pushes the class files to C:/product/jboss/shared/lib/classFolder:
We restart JBoss. Since classFolders take precedence over jars, JBoss will load the classes in C:/product/jboss/shared/lib/classFolder, which are identical to the classes in our Eclipse workspace.
We attach to JBoss and debug the project as a remote java application.
Pros:
We're able to push our new classes to JBoss and test them without backing up the original jars and copy/pasting the new ones by hand (jar hell).
Cons:
We're compiling twice -- once with the maven-compiler-plugin, and
once with an Eclipse project build (Java Builder).
The symlink functionality is hit or miss in my experience. Sometimes we need to
do the refresh project/close project/build project dance to get it to
work.
Is there a better way to do this? I cannot force them to restructure the project so heavily that all deployables are container-agnostic WARs, but our developers need to be able to make changes and quickly test them without manually copy/pasting .jars.
How old is old?
Have you looked at the Cargo plugin?
http://cargo.codehaus.org/Quick+start
It can deploy to JBoss 3.x.
It has a Java API so you should be able to write something to extend it to do what you want.
Why are you trying to deploying classes instead of jar files?
You can still remote debug via Eclipse with jar files.
Worst case scenario - use Ant.
Maven is not designed for this kind of stuff, trying to force it to work will just cause you pain.
Once you have got Maven generated the right artifacts, work out what you would do manually and then script it via Ant.
I would try looking at the maven-dependency-plugin which has the possibility of copying artifacts to different location.
Please check your Deployment Assembly (project -> properties -> Deployment Assembly) and verify if your maven libs are there.
I have an eclipse Tomcat project that has several dependencies on other eclipse projects.
For example imagine the main project is called server and has several dependencies:
server
(depends on):
data-lib
server-utils
messaging-utils
Currently every time I change data-lib,server-utils,messaging-utils I have to recreate the .jar file and copy it into WEB-INF/lib directory of server. At that point I export the server as a .war and deploy to my server.
I want to make this process work from the cmd line using ant (note I know maven is out there but I know ant pretty well from past experience so would prefer sticking to it for now). Its easy enough to create the build file for server -- it will end up creating a .war file. But I want it to automatically build the dependent libs. I want to do this while preserving my development workspace in Eclipse.
What is the easiest and cleanest way to do this? Currently my thought is each individual project will have its own build.xml (i.e. data-lib/build.xml , server-utils/build.xml , etc). I will have the server/build.xml do an antcall to these individual build files and then copy the jars to the server/WEB-INF/lib directory.
Is there an easier/better way?
if you want an Ant based script, I would go with Apache Ivy. The basic idea is that each of your submodule has its own build.xml file and publishes (via Ivy) their "publications" (like a Jar file) to a repository on the file system. The other modules then import these "publications" to build the final product.
I am not sure if it can help you, but in your WAR project, right-click on it in Package Explorer, and click on Properties.
There is a "J2EE Module Dependencies". In this option, select all of the dependencies (i.e. "data-lib", "server-utils" and "messaging-utils").
Now, when you modify a Java class in one of the dependencies, Eclipse will recreate the JAR file and deploy it directly in the WEB-INF/lib of your web application.
So I started with a web services project (just a dynamic web project) that builds and debugs correctly from eclipse. We've pulled a chunk of common code out that we want to put into a shared library so now those classes are going into a separate jar project that the web project references.
On the web project, I did Project->Properties->Java Build Path->Projects->Add and added the jar project. And this correctly solved all the compile-time classpath problems and everything builds fine. But at runtime, when the tomcat server fires up, spring attempts to inject some of the classes contained in the jar file and I get a NoClassDefFoundError.
My .class and properties files and the contents of my META-INF directory are showing up in the ./build directory, but my WEB-INF/lib directory seems to be referenced in-place, and the jar dependency doesn't get copied in to it to show up as part of the Web App Library.
What is the magical incantation to tell eclipse that the other jar project needs to be available to tomcat at runtime? From our ant build script, we first just build the other project into WEB-INF/lib and everything works fine, but not for eclipse debugging.
I figured this out after spending some time on it. If you are in Eclipse Helios , go to properties > deployment assembly > add > project and select the dependent project you wish to add.
Java EE module dependencies would solve this problem.
You have already done the task of extracting your common classes into its own project, possibly because other projects depend on these classes. Either way, you'll have to ensure that this is a Utility project (appears under Java EE in the project wizards), and not just a plain Java project.
One that is done, you can proceed to add the Utility project to your build path (compile-time path) as you have figured out.
The additional (final) step is to establish a Java EE module dependency between your Dynamic Web project and the shared library, which causes the utility's classes to be placed in WEB-INF\lib during deployment, and even during export of the WAR. To do so, visit the dynamic web project's properties, and browse to the Java EE module dependencies. Ensure that your utility project is selected here. Redeploy/publish your application and you should be good to go.