I imported my existing maven projects under eclipse.Once imported i found under Java Build Path > Source resource foulder is
excluded(i can see Excluded:**) from build and does not get copied under target > classes directory.
I can remove exclusion manually by selecting Excluded:** and then click Remove, But there are large numbers of projects. Is there
a setting in eclipse where i can do it one go ?
That's part of what Maven does when you let it generate your Eclipse project settings (via the eclipse:eclipse plugin/goal). It's quite misleading. However, if you have the m2e plugins installed into Eclipse it coordinates things correctly.
What's going on, as best as I can figure: Eclipse's built-in Java builder automatically copies non-Java files found on the build path to the output location (unless they're excluded as you see in your Build Path). Problem is, when Maven comes in the picture it, too, wants to copy resources during a build. So to keep the two builders from competing/interfering with each other, Maven instructs Eclipse to ignore resources so it (Maven) can manage copying them during a build.
m2e integrates into the Eclipse build process to do the Maven copying of those files, so if you configure the project as an m2e project things will "just work," both in Eclipse and if you build from a command line.
I don't know of a way to tell Maven to not configure the project this way. To be honest, that's just one of the reasons I prefer to not let Maven generate my Eclipse project files; I do a much better job of it and I totally control the specifics rather than relying on whatever the Maven eclipse developers think is best.
This is an old question, but I've been looking for the answer and I finally dug it up myself. According to the M2Eclipse FAQ the import intentionally excludes resources. This is because Maven performs special resource handling that includes filtering.
Let Maven do the building for you. Disable automatic building in Eclipse and never build your projects in Eclipse.
Related
Sourceforge.net has a filter for Java projects, but I'm looking for a way to narrow them down to ones that are meant to be built in Eclipse.
Edit I'm using Eclipse Metrics and Omondo plug-ins to analyze open-source Java projects. I'm looking for a quick way to find Eclipse open-source projects that can build quickly in Eclipse, so I can use these tools on them for analysis.
I presume that a project that is "meant to be built in Eclipse" is one that has an Eclipse .project file and other stuff checked into the source repository.
First, checking in Eclipse-specific stuff can a bad idea because it is easy to include stuff (e.g. build pathnames, preferences) that are specific to the developer. You then get problems if there are multiple committers ...
Second, this should unnecessary. Most of the stuff in the .project file can be generated when you import the project. If that's not possible, then the project should provide instructions for setting up the buildpath etcetera. (Note that if the project uses Maven, this is all taken care of for you.)
Third, any project worth its salt will include build scripts of some kind that allow you to rebuild without using any IDE.
Finally, any project that only supports building using Eclipse is excluding the significant subset of developers who use other Java IDEs.
Note that neither Maven or Ant builds require Eclipse to work. Both of these build tools can run from the command line, or from other Java IDEs.
OK. I understand your requirements now. You don't actually care what the project is ... or that it is sound / worthwhile project. You just need it for testing your plugin. (I won't comment on the "validity" of doing this. It depends on what you hope to achieve.)
I suggest that you install the m2eclipse plugin and look for projects with a "pom.xml" file. The projects don't need to be eclipse specific. The m2eclipse plugin automatically creates the ".project", ".classpath" and so on based on the "pom.xml" file. There's no need to exclude any particular version control system, because the m2eclipse plugin can import Maven projects that you checked out from the command line.
I've been asked to apply Maven to a project. After browsing a dozen sites it appears that it's quite vast and I'm not familiar as I'd like with similar tools like Ant. Why is it used/preferred and what does it offer over a standard Eclipse project? Also, how could it be added to an existing project?
Why is it used/preferred and what does
it offer over a standard Eclipse
project?
It is a build tool which can build your project without the need for an IDE like Eclipse. It can create a jar or war or other artifacts from the source, performing a bunch of steps like compilation, running unit tests, etc.
Where maven scores over ant is in managing third-party dependencies and in convention over configuration (which mean less lines of build script if you follow convention).
Also, how could it be added to an
existing project?
You start by creating a new maven project, following the step here.
Place it in the root folder of your project
If your source and resource files do not follow maven folder convention, update maven properties suitably referring to this documentation.
Run mvn package
It will fail if it needs any third party dependencies, which you can add as specified in the doc
With some trial and error, you should have your project running with maven, possibly, much quicker than if you were to set up the same with ant.
Others are already provided sufficient resources to read more about maven.
I suggest to start reading here:
http://www.sonatype.com/books/mvnref-book/reference/public-book.html
Maven is a great tool when you know how to use it. Maven (at core) is a dependency manager.
You include in your pom.xml (similar in function to the build.xml from Ant) all the librairies your project depends on (example : apache commons) along with their version and Maven get them directly from a repository (by default, the central maven repository)
Then you do not have to manually install any jar to make your project work. All is downloaded and cached on your local machine. You can even create an enterprise repository where you put all the jars needed by your company
Maven uses the concept of artifacts which are pre-built library projects with their own dependencies
To mavenize a project, you'll have to write a pom.xml describing your project (examples are numerous), get rid of your libs directory (or whatever classpath you described under Eclipse) and add all your dependencies to your pom.xml
You could also check Mavenizer for a first-start
But Maven is a lot more what i've just said. Read the docs, read poms from librairies and you'll get used to it quickly ;-)
If you use the M2Eclipse plugin from Sonatype, it's just a matter of right clicking the project in the package explorer and choosing Enable Dependency Management in the Maven menu. You are also advised to adjust the directories that contain the sources to the Maven standard directory layout but if you absolutely can't, you can configure that later.
Apart from that: Well, look for tutorials and documentation (for example there is the free book Better builds with Maven. Maven is very complex (yes, I don't think it is simple) and very powerful.
I'm working on a swing project, using maven2 (from command-line) and eclipse (without maven integration). So, I generate the eclipse project through maven eclipse plugin (mvn eclipse:eclipse), import it inside eclipse, and do all my work.
My problem is: when I run my app in eclipse (as a Java Application), I can't find none of the resources that are in my src directory. Digging for information on my problem, I get into this answer from another question. So, I compared the output from the following instructions:
MyClass.class.getResource("/").getPath();
MyClass.class.getProtectionDomain().getCodeSource().getLocation().toString();
Those gave me the following outputs, respectively:
${workspace_loc}/${my_project}/target/test-classes/
file:/${workspace_loc}/${my_project}/target/classes/
Checking the above locations, I could see that the former is empty, while the other one contained all my compiled classes and resources. So, I came to the conclusion that the classloader is looking for my resources in the wrong place. So, I think I have three questions:
Is my understanding correct?
If so, how it does to find the classes it is loading?
How do I solve this?
UPDATE: I've changed my code, so instead of invoking MyClass.class.getResource(...) or MyClass.class.getResourceAsStream(...), I'm now using ClassLoader.getSystemResource(...) and ClassLoader.getSystemResourceAsStream(...). In this way, everything is working fine in eclipse. I just don't know exactly why. Any hint on this?
Two possibles cases for me :
You are using eclipse to compile your project. Then eclipse is configured to exclude (or not include) resources in the src folder. You can set it in Project/Properties/Java Build Path/Source. Then you expend your src folder, and ensure you have something like "Included All", "Excluded None".
You run your maven application using maven to compile and not eclipse, even though you are using eclipse as your IDE. Then by default maven will not copy resources from the source folder to the output folder... Because it is not the standard maven way of doing things. Thus the resource are missing from the classpath and you don't find them. Just change your maven configuration to also include resources from your source folder.
I think you have to add src/main/resources to the build path. This is done in Project Properties > Build Path > Source. Here is how the standard maven project looks:
In future when using Eclipse I suggest to use m2eclipse plugin and create project using it. This will automatically make sure that all these folders are in the build path.
Try this:
Run configurations... -> Classpath -> User Entries -> Advanced... -> Add Folders
Can you try loading the resources using below?
this.getClass().getClassLoader().getResourceAsStream(propertyFileName)
This might be useful information
Eclipse Maven plugin has its own Classpath Container that conflicts with generated class paths when enabled.
What I would suggest is stop using eclipse:eclipse (sorry - harsh I know). I used it for about 8 months, cant believe it took me that long, and used M2Eclipse. M2Eclipse is an eclipse plugin in which you do the following.
Enable Dependency Management.
Update Project Configuration
(In Eclipse) Project -> Build Project
(In Eclipse) Run Application
It may not seem it, but its a much easier and less frustrating way of doing it.
Before, with eclipse:eclipse. You would have to run it then hit refresh and hope that everything is configured - if you have a multi-module pom things can really go wrong.
For me the Files within the WEB-INF were not getting included. Hence I added them to Buildpath (Project -> Build Path -> Configure Build Path -> Add folder (project/src/main/webapp). This resolved the issue.
I will ask my question short and sweet, is there any formal way to write code using IDE and then build them using manual build process.If anyone has good links on internet, it is better to give
I believe it's easy, and what is more important - convenient, in cases when your IDE project is based on some external build model e.g. Ant, Maven, probably SBT for Scala. In this case it's easy for external build to be synchronized with IDE. Also it's important whether your IDE monitors underlying filesystem changes inside project folder, as I believe it's going to be quite pain-full to click "Refresh" or something similar every time you build.
Popular IDE's provide options to import project from external models like Ant and Maven.
Personally I use this approach in one of my projects with Java, Maven and IntellijIdea.
Yes. Use maven. It has plugins to all popular IDEs. So, create maven project, write pom.xml, run mvn install and then run mvn eclipse:eclipse (if you are using eclipse).
This will produce .project and .classpath. Now open eclipse, define classpath variable M2_REPO and import your project.
M2_REPO should be defined only once and should refer to local maven repository that is typically located under USER_HOME/.m2/repository.
For more details see documentation of maven.
I did not know this and always spent a lot of time synchronizing my IDE and ant build.xml. But now I am using maven and can forget about this hard work.
Perhaps the reason I stalled learning Java until now is because I HATE how Java handles external libraries. I'm stuck keeping them in one place, adding them individually, fixing problems with versioning and every time I move/rename them, and copying and writing the classpath over and over each time I release a Java application.
There has to be an elegant solution to all of this. I keep all of my libraries (regardless of task, platform, or other) in their own little folder inside a "lib" folder in my development folder, kind of like this:
Dev
-lib
+JS-jQuery
+Flex-Degrafa
-Java-Xerces
+Xerces-1.2.3
+More libraries
I can use either Netbeans or Eclipse for Java dev, but none of them provide a very streamlined (and not to mention idiot-proof) way of managing all of these.
A nudge in the right direction or an online article/tutorial on this would be greatly appreciated.
You can either use Ant + Ivy or Maven to manage your library dependencies.
If it is only dependency management you're after and you're happy with the rest of your build process, I would use Ivy, as it can unobtrusively manage your dependencies, leaving your existing build process intact. There is a plugin for Eclipse called IvyIDE that contributes your dependencies via a classpath container.
Maven 2 has a steeper learning curve but provides a much richer set of functionality for building your projects and Eclipse integration through m2eclipse or IAM.
Personally I use Maven as I have a large number of projects to work with and Maven is particularly suited to efficient development across lots of projects.
Have a look at the introductory documentation to see what works for you.
Ivy Tutorial
Maven Getting Started Guide
Netbeans 6.7.1's Maven support is quite good and comes out of the box with the IDE.
The Eclipse addon was frustrating enough that I gave Netbeans another try.
A third choice besides ChssPly76's options is to use Ant with the Maven Ant Tasks. I don't know if I'd call any of these solutions particularly "elegant," but they do spare you the need to manage your own lib/ directory and classpath variables.
If you're working on Linux you can install Java libraries with APT or RPM.
Otherwise, I normally check precompiled JARs into a lib directory in my project's version control repository and make sure the names of the JAR files include full version information. E.g. lib/foo-1.5.6.jar, not lib/foo.jar.
To avoid having to manually set the classpath before running your app, you can set the classpath in the Manifests of the JARs themselves to define the dependencies of each JAR file. The JVM will follow all the dependencies when loading classes.
Maven is often more trouble than it's worth, but the ability to open a maven project directly into IDEs such as IntelliJ is excellent. For example, IntelliJ will download all dependencies and have them available without having to run a build first, or an mvn command and then a project refresh. It also isn't necessary to re-generate the project every time a dependency is added. I work with a number of Eclipse developers who switched to IntelliJ for this alone.
However, one shortfall of Maven is that many libraries (or versions of libraries) are not available on public repositories. Therefore it is often necessary to set up a local repository such as archiva. In ant, it would just be a matter of adding it to the lib directory in the repository.
Maven can also attack when you need to do something that maven doesn't directly support via a plugin. What would normally be a few lines of ant can often turn into a morning's worth of work.
Finally, buildr is an excellent way of using Maven's dependency management and plugins, while also supporting ad-hoc tasks.