I'm new to maven. I'm still failing to grasp the concept of it.
For example I'm looking for com.extjs:gxt:jar:2.2.5 or org.syslog4j:syslog4j:jar:0.9.46. I can't find them in any repo. Yet they seem fairly common packages.
Does that mean I have to download them by hand ? Doesn't it defeat the whole idea of maven ?
Where can I find a good repository that will have all these artifacts so that I don't need to download the jars by hand ?
What am I doing wrong when using maven, this definitely does not seem the way to go...
You're not doing anything wrong. The issue is that those artifacts don't exist in maven central repository. By default, that's the only repository maven will download from. You can add additional repositories (see maven docs) to configure repositories that aren't mirrored to central automatically.
As #Michael said, you are not doing anything wrong.
The default Maven central repository is not going to provide every possible artifact on the earth.
Normally you can have two way to solve it:
1) The artifact you use may be provided by some organization, which they provide their own repository to host those artifact. Tell Maven to lookup those repositories so that Maven can retrieve the corresponding artifact.
or
2) Get the JAR etc and put in your local environment.
There are two most commonly used ways for the above work:
A) Have a "local" maven repository/proxy (e.g. Nexus, Artifactory), and make your Maven points to this repository. Adding new remote repository (1) is mostly done by adding extra repo to proxy under your local Maven repo. Manually handling 3rd party artifact (2) is done by deploying the JAR to your local repo.
B) All done locally by your local Maven. Adding new remote repo (1) is done by updating the settings.xml (or your project POM.xml). Manually handling 3rd party artifact (2) is done by installing 3rd party JAR to local repository.
you can use
<dependency>
<groupId>com.extjs</groupId>
<artifactId>gxt</artifactId>
<version>2.3.0-gwt22</version>
</dependency>
Related
We have a dependency third-party library that is available online in jar form, but it is not in Maven Repository, or known to be in any other repository.
How can we use pom.xml to auto-retrieve this dependency, based on a URL?
We don't want to store it in our Git repo, because that's A Bad Thing.
The idea here is that when people check out the project, they can use their IDE Maven integration (or just mvn command line tools) to download all the dependencies. So we would want to be able to also download this other third party dependency just like all the ones in Maven repo.
I have not been able to come up with an answer to this based on searches -- all solutions seem to be "download it first and create a local repo." Obviously Maven can download from the Internet, since that's how it connects to Maven Central and other repos. So I don't see why it cannot download arbitrary URLs that present packages in recognizable formats.
Long term, the best solution is to use your own artifact repository like Nexus, Artifactory or Archiva.
All of these have a manual upload function that you can use to set the groupId, artifactId and version, so you can then refer to the artifact as usual.
If you want to go really low tech, I think you can just put some machine's local repository behind an Apache, provided you grant read/write access.
Then you need to add your new repository in the Maven settings.xml file, as described here.
Maven uses the coordinates to navigate the repository (which has a specific layout) and verify artifact checksums for corruption/tampering using metadata files in specific locations of the repo.
AFAIK this is similar to other package management systems like APT and RubyGems that use repo manifests and don't allow arbitrary URL downloads.
Skipping the repository manager
If you really don't want or can't use a repository manager, you can always download the artifact and manually install it using the Maven Install Plugin:
mvn install:install-file -Dfile=your-artifact-1.0.jar -DgroupId=org.some.group -DartifactId=your-artifact -Dversion=1.0
However, you'll have to do this on every machine that runs the build, every time that artifact needs to change.
Unfortunately, my project has an external dependency that was never published to any Maven repository. The only way I can get it is by direct download from github (they pushed the binary to github).
One (bad) way is to download the jar manually and commit/push it to my code repository (git). It wouldn't help me to manually deploy this artifact in my local binary repository because I share this project with external contributors that cannot access my private binary repo.
I wonder if maven has a better way to handle this? (Given that I can't upload the artifact to my repo or public repo).
I know that npm allows getting some dependencies from URL. Does maven support it as well?
AFAIK there is no nice way to handle this. You could
Write a script that downloads the jar and installs it in your local Maven repository. This script could be shared through your code repository.
Include downloading and installing the artifact into the Maven build process (by writing a Maven plugin or using the antrun plugin)
Set up a nexus in the cloud that everyone in your team can access.
For my project I need to store jar after each build at some other url. Is there a way to get it done by Jenkins job.
I am quite new to jenkins.
You can find a good explanation on how to publish your artifact to a repository (best practice) here. This is equivalent for Maven3 and Maven2.
The answer refers to Artifactory. Make sure to also take a look at Nexus and Archiva as khmarbaise noted.
tl;dr
If using Artifactory, add the Maven Artifactory Plugin to your pom.
We do not have our own repository at the moment. So, when we build with maven it creates .m2 repository in the home directory of the current user.
Now there are two third party jars which are not found in the Maven Central. Suppose one of them is hasp-srm-api.jar. Today the process is this:
a. The pom.xml of the project depending on hasp-srm-api.jar contain these lines:
<dependency>
<groupId>com.safenet</groupId>
<artifactId>hasp</artifactId>
<version>1</version>
</dependency>
b. Before doing the first build we execute the following command:
mvn install:install-file -Dfile=hasp-srm-api.jar -DgroupId=com.safenet -DartifactId=hasp -Dversion=1 -Dpackaging=jar
My question is this - is it possible to automate this step? I would like to be able to tell maven to check whether the hasp artifact exists and if not - install it manually using the aforementioned command line. How can I do it?
NO. It is not possible to have maven automatically deploy an artifact into a repository in the fashion you suggest. This goes for both local and remote repositories. If the artifact exists in a some repository somewhere, you can add that repository to your build's list of known remote repos, but other than that you have to add it yourself.
You can add it to your local .m2 repository, but that will then only be good for that individual environment. Other dev's will have to repeat the process. This is one of the main attractions of running your own repository server( like Nexus ); you can add the artifact to that repository and then everyone in your organization can use it forever. There is still no way to automate the deployment of the artifact, but it's easy to do and is permanent.
Note, setting up a repository manager is very easy to do. It's highly recommended. It makes the whole Maven thing make a whole lot more sense.
The best solution for such problems is using a repository manager which results in installing such kind of dependencies only once into the repository manager and the whole company can use it a usual dependency. That's it.
Other option you have is to write your own maven plugin. May be below link will be right place for you start
MOJO FAQ
I've refactored all repository configuration out of my various projects into a parent pom that I've created for the specific purpose of having a single point of configuration for stuff like repo's and distribution management. This is supposed to be best practice as I understand it. In deployed my parent pom to the nexus server, and then tried to run my child projects. They can't find my parent pom . . . this kind of makes sense to me since, wihtout the parent pom they don't know about the nexus repo . . . seems like a chicken and egg kind of thing? Am I missing something obvious?
It's true that your project needs to know where to find the repositories to download its dependencies. But before going to external repositories, Maven will check your local repository to see if the artifacts it needs are in there. Does your local repository contain the parent pom? If not, you can add it by running
mvn install
on the parent pom. The problem may have been caused by deploying the parent pom directly to Nexus, bypassing your local one. You can avoid this in future by deploying using
mvn deploy
This will first install the artifact locally, and then deploy it to the external repository (Nexus, in your case). More details here: http://maven.apache.org/guides/introduction/introduction-to-the-lifecycle.html
If you're in a situation whereby your parent pom is built and deployed by others, this won't help. You can either specify the repositories in your project's pom, or in your local settings.xml. A common approach is to expect all developers to include a repository definition in their local settings.xml which points to your Nexus repository, using it as a mirror for all other repositories. You can then configure each external repository you need in Nexus, and let it retrieve any dependencies you need for you. I'm not familiar with Nexus, but more details on mirroring can be found here: http://maven.apache.org/guides/mini/guide-mirror-settings.html
You must maintain the repositories definitions for each child (maven module), this is main best practice in a build process: "Make the build portable".
Any developer/system should be able to build any module without source dependencies to the parent or other modules, only with the repository reference.