如何将本地项目（不是 jar）作为依赖项添加到 Maven 项目

Question

I have two Maven projects that I've added to one Intellij Idea's project as two modules. Project B depends on Project A.

Here are simplified versions of their pom.xml files.

Project A:

<?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.group</groupId>
    <artifactId>a</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
    </dependencies>
</project>

Project B:

<?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.group</groupId>
    <artifactId>b</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>jar</packaging>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>com.group</groupId>
            <artifactId>a</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>
    </dependencies>
</project>

Project A compiles easily since it has no dependency. But Project B depends on Project A and since I'm not telling maven how to find it, it can not be compiled with mvn package . But if I'm not mistaken, this was possible using Intellij Idea's "Meven Projects" menu since to Intellij Idea both projects are known.

But right now, for some unknown reason, I can not compile project B even in Intellij Idea. When I do, it prompts:

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

My question is, how can I include one project into other as its dependency? Please note that I'm not looking for a local dependency injection in maven since I want this to work in the future when I upload my packages into some repository.

Answer 1

Your project B depends on project A and you have already specified this as a dependency in your pom file. The only reason project B is not able to find project A may be due because of project A artifact is not installed in your local .m2 repository. So you have to first do a mvn clean install of your project A which will create the artifact in your maven repository. You should be then able to use artifact A in project B.

Answer 2

Since I came here searxing for the same problem with Eclipse and it is mentioned in some comments (where it seems the IntelliJ focus is not obvious) I want to point to this solution for Eclipse that may be similar to IntelliJ as well: https://stackoverflow.com/a/10696646/1915920

The crucial point for us was the dependent projects pom.xml version match (in the dependent and depending pom.xml ) in the workspace, so the workspace resolution works.