Java – compile a multi module Maven project without installing it into a local repository

There is a compilation (and packaging) problem in my multi module Maven project There was a problem compiling one of the two projects, which are sibling projects and contained in the parent project, and the other project depends on the other project For simplicity, I sketch the project folder structure and POM XML content

Folder structure

-parent
|
|-child1
| |-src
| |  |-main
| |     |-java
| |        |-Child1Class.java
| |-pom.xml
|
|-child2
| |-src
| |  |-main
| |     |-java
| |        |-Child2Class.java
| |-pom.xml
|
|-pom.xml

Parents' POM xml

<?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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <groupId>com.example.project</groupId>
    <artifactId>parent</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <name>parent</name>
    <modules>
        <module>child1</module>
        <module>child2</module>
    </modules>
</project>

POM of Child1 xml

<?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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.example.project</groupId>
        <artifactId>parent</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <groupId>com.example.project</groupId>
    <artifactId>child1</artifactId>
    <version>1.0-SNAPSHOT</version>
    <name>child1</name>
    <dependencies>
        <dependency>
            <groupId>${project.groupId}</groupId>
            <artifactId>child2</artifactId>
            <version>${project.version}</version>
        </dependency>
    </dependencies>
</project>

POM of child2 xml

<?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/maven-v4_0_0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>com.example.project</groupId>
        <artifactId>parent</artifactId>
        <version>1.0-SNAPSHOT</version>
    </parent>
    <groupId>com.example.project</groupId>
    <artifactId>child2</artifactId>
    <version>1.0-SNAPSHOT</version>
    <name>child2</name>
    <dependencies>
    </dependencies>
</project>

As shown in the figure, child2 is a dependency of Child1 Child1 and child2 are developed in parallel Therefore, after any source code changes in child2, Child1 should be compiled and deployed without any other operations But I can't successfully compile Child1 This error message appears after running the MVN compile command on Child1:

[ERROR] Failed to execute goal on project child1: Could not resolve dependencies for project com.example.project:child1: jar:1.0-SNAPSHOT: Could not find artifact com.example.project:child2:jar:1.0-SNAPSHOT -> [Help 1]

As I've seen, Maven tries to search the local repository for child2 If I run the MVN install command on the parent project, both projects will be added to the local repository Then any attempt to compile Child1 is successful This seems like a solution, but it's inconvenient What I want is to compile Child1 and write Child1 and child2 at the same time without installing into the local repository

Solution

Try MVN compile - pl: Child1 - am, where - PL is the project you want to build, and - am tells Maven to build the dependencies of these projects if they are part of a multi module project