Merge multiple spring web projects into one deployable war

Question

Please help to find solution to merge two or more spring web projects into single deployable war file. I have following projects

myproject 
  a. core 
    - src
    - pom.xml
        - packaging = jar
  b. dao 
    - src
    - pom.xml
        - packaging = jar
        - dependency on core project
  c. service
    - src
    - pom.xml 
        - packaging = jar
        - dependency on core and dao projects
  d. salem-web
    - src
    - pom.xml
        - packaging = war
        - dependency on core, dao and service projects

So far it is good. But I have a new requirement, for different customers we can have (customer specific features) salem-web-customer1, salem-web-customer2 etc..

  e. service-customer1
    - src
    - pom.xml 
        - packaging = jar
        - dependency on core and dao projects

  f. salem-web-customer1
    - src
    - pom.xml
        - packaging = war
        - dependency on core, dao and service-customer1 projects

We need to deploy salem-web & salem-web-customer1 as one package for customer1 and so on for other customers.

I already tried solutions provided by maven overlays and other threads without any luck. Could you please suggest the correct configuration (if possible) to merge two web projects into one.

Answer 1

There are a few possibilities, you could do it like this:

Have a parent pom :

<?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>salem</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>pom</packaging>

    <modules>
        <module>core</module>
        <module>dao</module>
        <module>service</module>
        <module>service-customer1</module>
        <module>salem-web</module>
        <module>salem-web-customer1</module>
    </modules>

</project>

Have projects with dependencies for each jar and war project, for example

<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>service-customer1</artifactId>
  <version>1.0-SNAPSHOT</version>
  <packaging>jar</packaging>

  <name>service-customer1</name>
  <url>http://maven.apache.org</url>

  <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <dependency>
      <groupId>com.greg</groupId>
      <artifactId>core</artifactId>
      <version>${project.version}</version>
    </dependency>
    <dependency>
      <groupId>com.greg</groupId>
      <artifactId>dao</artifactId>
      <version>${project.version}</version>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
</project>

And for a war project:

<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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>

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

    <artifactId>salem-web-customer1</artifactId>
    <packaging>war</packaging>

    <name>salem-web-customer1 Maven Webapp</name>
    <url>http://maven.apache.org</url>

    <dependencies>
        <dependency>
            <groupId>com.greg</groupId>
            <artifactId>core</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>com.greg</groupId>
            <artifactId>dao</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>com.greg</groupId>
            <artifactId>service-customer1</artifactId>
            <version>${project.version}</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <finalName>salem-web-customer1</finalName>
    </build>

</project>

When you build the whole project you will have all the wars you need in the different target folders:

./dao/target/dao-1.0-SNAPSHOT.jar
./salem-web/target/salam-web.war
./salem-web-customer1/target/salem-web-customer1/WEB-INF/lib/core-1.0-SNAPSHOT.jar
./salem-web-customer1/target/salem-web-customer1/WEB-INF/lib/dao-1.0-SNAPSHOT.jar
./salem-web-customer1/target/salem-web-customer1/WEB-INF/lib/service-customer1-1.0-SNAPSHOT.jar
./salem-web-customer1/target/salem-web-customer1.war
./service/target/service-1.0-SNAPSHOT.jar
./service-customer1/target/service-customer1-1.0-SNAPSHOT.jar