Gradle build.gradle to Maven pom.xml
MavenGradlepom.xmlMaven Problem Overview
I have a Gradle project and I need all its dependencies to be transferred and used with another Maven project. In other words how can I generate (or can I generate) the pom.xml from the build.gradle?
Maven Solutions
Solution 1 - Maven
Since Gradle 7, when using Gradle's Maven-Publish plugin, publishToMavenLocal and publish are automatically added to your tasks, and calling either will always generate a POM file.
So if your build.gradle file looks like this:
plugins {
id 'java'
id 'maven-publish'
}
repositories {
mavenCentral()
}
dependencies {
implementation group: 'org.slf4j', name: 'slf4j-api', version: '1.7.25'
runtimeOnly group: 'ch.qos.logback', name:'logback-classic', version:'1.2.3'
testImplementation group: 'junit', name: 'junit', version: '4.12'
}
// the GAV of the generated POM can be set here
publishing {
publications {
maven(MavenPublication) {
groupId = 'edu.bbte.gradleex.mavenplugin'
artifactId = 'gradleex-mavenplugin'
version = '1.0.0-SNAPSHOT'
from components.java
}
}
}
you can call gradle publishToLocalRepo
in its folder, you will find in the build/publications/maven subfolder, a file called pom-default.xml. Also, the built JAR together with the POM will be in your Maven local repo. More exactly the gradle generatePomFileForMavenPublication
task does the actual generation, if you want to omit publication to your Maven local repo.
Please note that not all dependencies show up here, since the Gradle "configurations" don't always map one-to-one with Maven "scopes".
Solution 2 - Maven
As I didn't want to install anything in my local repo, I did following, instead, after reading docs. Add in your build.gradle
apply plugin: 'maven'
group = 'com.company.root'
// artifactId is taken by default, from folder name
version = '0.0.1-SNAPSHOT'
task writeNewPom << {
pom {
project {
inceptionYear '2014'
licenses {
license {
name 'The Apache Software License, Version 2.0'
url 'http://www.apache.org/licenses/LICENSE-2.0.txt'
distribution 'repo'
}
}
}
}.writeTo("pom.xml")
}
to run it
gradle writeNewPom
@a_horse_with_no_name
gradle being made with groovy can try to add after ending } project block
build{
plugins{
plugin{
groupId 'org.apache.maven.plugins'
artifactId 'maven-compiler-plugin'
configuration{
source '1.8'
target '1.8'
}
}
}
}
didn't try, wild guess !
Solution 3 - Maven
When you have no gradle installed the "write gradle task to do this" is not very userful. Instead of installing this 100MB beast with dependecies I made the filter converting gradle dependencies to maven dependencies:
cat build.gradle\
| awk '{$1=$1};1'\
| grep -i "compile "\
| sed -e "s/^compile //Ig" -e "s/^testCompile //Ig"\
| sed -e "s/\/\/.*//g"\
| sed -e "s/files(.*//g"\
| grep -v ^$\
| tr -d "'"\
| sed -e "s/\([-_[:alnum:]\.]*\):\([-_[:alnum:]\.]*\):\([-+_[:alnum:]\.]*\)/<dependency>\n\t<groupId>\1<\/groupId>\n\t<artifactId>\2<\/artifactId>\n\t<version>\3<\/version>\n<\/dependency>/g"
This converts
compile 'org.slf4j:slf4j-api:1.7.+'
compile 'ch.qos.logback:logback-classic:1.1.+'
compile 'commons-cli:commons-cli:1.3'
into
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.+</version>
</dependency>
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.1.+</version>
</dependency>
<dependency>
<groupId>commons-cli</groupId>
<artifactId>commons-cli</artifactId>
<version>1.3</version>
</dependency>
The rest of pom.xml should be created by hand.
Solution 4 - Maven
The most built in solution would likely be to use the archiveTask
task in the Maven Plugin which will generate a pom in the poms
folder in your build dir. http://www.gradle.org/docs/current/userguide/maven_plugin.html#sec:maven_pom_generation
Solution 5 - Maven
Add this to your build.gradle
file. I pasted it to the end of mine:
apply plugin: 'maven'
apply plugin: 'java'
task writeNewPom doLast {
pom {
project {
groupId 'org.example'
artifactId 'test'
version '1.0.0'
inceptionYear '2008'
licenses {
license {
name 'The Apache Software License, Version 2.0'
url 'http://www.apache.org/licenses/LICENSE-2.0.txt'
distribution 'repo'
}
}
}
}.writeTo("$buildDir/newpom.xml")
}
Then run the following depending on which you have
$ gradle writeNewPom
or
$ /.gradlew writeNewPom
The file is generated and put in $buildDir/newpom.xml
Snagged from this gist