I have a ant build.xml file , how can i directly create a maven pom.xml which is exactly equivalent of build.xml file ? I know that I can create a maven project and move the folder of build.xml to appropriate folder of maven directories, But is there any automated way of doing this ?
ANT and MAVEN are different so there is probably no such complete automation really.
Still there are some attempts to automate it (see: https://github.com/ewhauser/ant2maven/blob/master/ant2maven.groovy and its forked repositories).
Another approach may be to create a pom.xml file and use https://maven.apache.org/plugins/maven-antrun-plugin/ to include the ANT script in it.
The simple answer is no. There is no easy way to generate a POM.
In my opinion switching to Maven is best left to new projects with little or no legacy to defend. In short Maven is a highly opinionated build tool that follows a standardized build workflow. ANT, on the other, ANT is gloriously configurable... resulting in no two builds working the same way :-)
A secondary problem is that few ANT builds properly record the origin and version of their 3rd party dependencies...
In most cases you are better off keeping the existing ANT build logic and introduce dependency managment using a plugin like Apache ivy. This allows an ANT project to properly integrate with a Maven repository infrastructure. This further enables collaboration with other teams using alternative build tools like Maven, Gradle or SBT.
Related answers:
Migrating complex project from Ant to Maven - How to handle unusual folder structures?
Maven or Ivy? Which one is better with a system already in production? And the other differences?
Related
I'm a bit confused between maven assembly plugin and build-helper-maven plugin.
I've also read in the maven documentation that The assemblies/archive created by the Assembly Plugin gets deployed during the deployed phase.Hence, they can be deployed to the remote nexus repositories.
The purpose of maven assembly plugin is to archive many things into one(say in tar.gz format).
However, the attach-artifact goal present within build-helper-maven plugin has the same role i.e.archiving,installing and deploying the artifact.
With that being said,why would anyone use both of them together? I've seen people using both of them together. Isn't one of the plugins an alternative choice of the other?
Kindly advise.
If you use maven-assembly-plugin you can create as you already mentioned any kind of archives (range from very simple to very complex structures) they will be by default be attached to your project which means they will be deployed into remote repositories in one go if you do mvn deploy with no supplemental configuration.
The build-helper-maven-plugin is intended to add an artifact (one goal of this plugin) which is usually not generated by Maven itself which most of the cases is a smell. If people using them together (in the use case to create an archive and attach it) this makes no sense.
Apart from that the build-helper-maven-plugin can also be used to add other source directories for example for scala, kotlin projects (other goals for example add-source etc.)
So those plugins are not alternatives they have different intentions/use cases.
I have a legacy JAVA project and we use Ant to build it. We are planning to keep using ant for building the project but delegate the dependency management to maven/gradle without affecting the existing build process.
What might be the best way to move forward - with Maven or with gradle?
Since existing project has it's own structure(which may not conform to standard Maven archtypes), I know might have to make a custom archtype if using maven.
https://stackoverflow.com/a/48791837/2458858 provides one way to solve it but I am trying to find a standard solution in which I am able to delegate dependency management within the same project rather than a separate project.
I am new to gradle. I am looking forward to migrating from maven to gradle.
I had few requirements:
Existing project is maven based, and is generating a fat jar/uber jar. I am planning to split this into multiple projects, and creating smaller/thinner jars/libraries
I am currently evaluating the Multi-project Build support.
I have to also edit the Java source code, automatically, like making the java source modifications based on certain conditions
Publish the project as maven based, as other projects which need these split-up jars are still maven based.
I suppose Maven plugin can be used for publishing?
Would Gradle be a good, scalable solution for these two requirements which I am looking into currently?
Also please provide some pointers around these two topics.
Gradle has very good multi-project support, far better than Maven's. You can start with this documentation section
You can setup compilation of generated/auto-edited sources as well. Take a look at this forum post, discussing compilation of sources created from database using hbm2dao
You can setup publishing of projects using the Maven plugin. pom.xml files will be generated automatically
I have an Ant script for automating a few tasks that are not build related by mainly as updates to the EAR file. These include calling SoapUI exe for some web services, unpacking the EAR file modifying a few classes and repacking it.
Now, for some reason I would like to do the same using maven scripts. From going through Stack Overflow and maven tutorial, I find that this can be replicated using Ant plugins inside maven. Also, I could not find direct substitutes for unpacking the EARs or calling executables in maven. This scripts will not have anything to do with the standard build process that maven is meant for and only caters to some cleanup or update of already deployed EAR.
So how do I go about this? Use Ant plugins inside maven or is there a better maven way to do this?
Thanks,
This may be an incomplete answer but -
Maven is more of a framework and it's going to want to build your application. What it will not do is modify source. It will process source files (.java, .ear, whatever) and put them in a target/ directory. Of course anything is possible (re: hackable) but this is off the rails as far as Maven is concerned if you want in place modification of source - besides, isn't the point of source that it's source, and if you're automating a task that should be part of your build, deploy, startup, etc.?
Maven resource filtering is how to process a source file and stamp dynamic information into your resources.
If you can provide more information regarding how you are processing your .ear files exactly you can possibly put together the pieces in the Maven process resources phase using existing plugins. Worst case you can write your own plugin.
We are trying to migrate our builds from ant to maven. Project I am working for is using ant since ages. Scripts are real complex where build artifact is a zip file having a definite directory structure. Build creates about 108 unique jars and packages them to this zip file along with many config files and other 3rd party jars.
We need this zip file to be same as now even after migration to Maven. I am just a learner on Maven as of now. My question to you guys is that if there is a way using which I can use one pom.xml to produce more that one jar file, providing list of jars and includes, excludes packages for each.
I googled and found that in case we need multiple jars from one project but different packages, we can do so by placing one pom.xml at each package (jar will be created from this package) and bonding all using dependency management.
But this does not solves my problem, as having 100+ pom.xmls does not seems to be a good idea.
Hope I have made my question clear. Please suggest if there is a way out.
Adding to Udo's answer here's another Sonatype blog posting with a diagram explaining the Maven anti-pattern of generating multiple jars from a single Maven project.
Both articles recommend adopting a modular structure to your code rather than fighting Maven's approach of decoupling large projects into a set of interrelated sub-modules.
Incremental publish approach
Start with looking at the arifacts you actually plan to share. Your mail suggests that the only file you're actually publishing is a large zip file containing 100+ jars and other files?
You could invoke the Maven command-line tool to publish this zip to the Maven repository:
mvn deploy:deploy-file \
-Durl=$REPO_URL \
-DrepositoryId=$REPO_ID \
-DgroupId=org.myorg \
-DartifactId=myproj \
-Dversion=1.2.3 \
-Dpackaging=zip \
-Dfile=myproj.zip
This approach can also be used to publish jars and POMs (containing dependencies). Eventually you'll be overwhelmed with the number of POMs to maintain.... AT which time it would be simpler to restructure the building of that jar into a sub-module.
Alternative to switching build technology
It's very difficult to walk away from a legacy ANT build. These often contain complex, custom and difficult to reproduce build logic. For such projects I recommend using Apache ivy to externalise 3rd party dependencies and share artifacts with other projects (who might be using Maven).
To that end I wrote an ant2ivy script for generating an initial ivy setup, based on the jars that already exist in the ANT project's directory (normally committed alongside the source).
Using ivy doesn't get you away from the fact that it's a good idea to create project sub-modules. However it does enable you to modernise your ANT build.
Update
Yes, there are Maven ANT tasks available. I don't use them because they based on Maven 2. I'm disappointed that we're still waiting for their Maven 3 replacement aether-ant-tasks (Only available from GitHub). Ivy is still the no1 choice for integrating non-Maven clients with a Maven repository
Well you can generate multiple jars out of one project.
Its not really considered best practice. Look at the supplied article and decide it yourself.
In the includes your are not limited to packages, however this surely makes it easier. :)