Building EAR from a single Maven project

Question

There is a Maven project that used to have JAR packaging type. Now the project has evolved, and it is required that it be built as EAR, including the JAR proper and its dependencies altogether.

Does it necessarily mean I have to introduce the second POM with EAR packaging type? Is it possible to build JAR+EAR from a single Maven project? The reason behind that is that I don't really want to radically reorganize my repository structure.

If not possible, I guess I'd need to somehow reorganize project structure to make use of Maven modules. What (sub)module structure would you recommend in that case?

Answer 1

You will need 3 poms, here is a working example;

pom 1 is the parent

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>

  <groupId>com.greg</groupId>
  <artifactId>ear-example</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>pom</packaging>

  <name>ear-example</name>
  <modules>
    <module>example-jar</module>
    <module>example-ear</module>
  </modules>

</project>

pom 2 is the jar or war

<?xml version="1.0"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>com.greg</groupId>
    <artifactId>ear-example</artifactId>
    <version>1.0-SNAPSHOT</version>
  </parent>

  <artifactId>example-jar</artifactId>
  <packaging>jar</packaging>

  <name>com.greg</name>
  <url>http://maven.apache.org</url>
  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
</project>

pom 3 is the ear which has a dependency to the jar/war and uses the ear plugin

<?xml version="1.0"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <modelVersion>4.0.0</modelVersion>

  <parent>
    <groupId>com.greg</groupId>
    <artifactId>ear-example</artifactId>
    <version>1.0-SNAPSHOT</version>
  </parent>

  <artifactId>example-ear</artifactId>
  <packaging>ear</packaging>

  <dependencies>
    <dependency>
      <groupId>com.greg</groupId>
      <artifactId>example-jar</artifactId>
      <version>${project.version}</version>
    </dependency>
  </dependencies>

  <build>
   <plugins>
     <plugin>
        <artifactId>maven-ear-plugin</artifactId>
        <version>2.10.1</version>
        <configuration>
        </configuration>
      </plugin>
    </plugins>
  </build>

</project>

Answer 2

I think you can use maven war plugin to generate a single war file every time you build the project

 <build>
<plugins>
  <plugin>
    <groupId>org.apache.maven.plugins</groupId>
    <artifactId>maven-ear-plugin</artifactId>
    <version>2.3.2</version>
    <!-- configuring the ear plugin -->
    <configuration>
      <modules>
        <!-- all your modles -->
      </modules>
    </configuration>
  </plugin>
</plugins>