如何不使用任何插件将非Maven依赖项安装到Maven项目中？

Got it, let's tackle this problem step by step—since you need to include non-Maven repository JARs in your pom.xml and ensure they're properly resolved during mvn package in a CI environment, there are two reliable approaches you can use:

This method keeps your custom JARs directly in your project repository, so they're automatically pulled into the CI environment when the code is checked out.

• First, create a dedicated folder (like lib/) at your project root, and place all your non-Maven JARs inside it. This ensures CI has access to the files without needing external setup.
• Next, add the dependencies to your pom.xml using the system scope, with a relative path to the JAR:

<dependency>
    <groupId>com.yourteam</groupId> <!-- Custom group ID, use something consistent -->
    <artifactId>your-custom-library</artifactId> <!-- Custom artifact ID matching your JAR -->
    <version>1.0.0</version> <!-- Custom version number -->
    <scope>system</scope>
    <systemPath>${project.basedir}/lib/your-custom-library.jar</systemPath>
</dependency>

• Important note: System scope dependencies aren't automatically packaged into your final artifact (like a WAR or executable JAR). To fix this, add the maven-dependency-plugin to copy these JARs during the build:

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-dependency-plugin</artifactId>
            <version>3.6.1</version>
            <executions>
                <execution>
                    <id>copy-system-jars</id>
                    <phase>prepare-package</phase>
                    <goals>
                        <goal>copy-dependencies</goal>
                    </goals>
                    <configuration>
                        <includeScope>system</includeScope>
                        <outputDirectory>${project.build.directory}/classes/lib</outputDirectory>
                    </configuration>
                </execution>
            </executions>
        </plugin>
    </plugins>
</build>

This method treats your custom JARs like standard Maven dependencies, avoiding the limitations of the system scope.

• First, add a step in your CI build script to install the JARs to the local Maven repo before running mvn package. For example, if your JAR is in lib/, the command would be:

mvn install:install-file \
    -Dfile=lib/your-custom-library.jar \
    -DgroupId=com.yourteam \
    -DartifactId=your-custom-library \
    -Dversion=1.0.0 \
    -Dpackaging=jar \
    -DgeneratePom=true

• Then, add the dependency to your pom.xml just like any regular Maven dependency—no special scope needed:

<dependency>
    <groupId>com.yourteam</groupId>
    <artifactId>your-custom-library</artifactId>
    <version>1.0.0</version>
</dependency>

• Example CI script snippet (for GitHub Actions):

jobs:
  build:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - name: Set up JDK 17
        uses: actions/setup-java@v4
        with:
          java-version: '17'
          distribution: 'temurin'
          cache: maven
      - name: Install custom JARs to local repo
        run: |
          # Repeat this command for each custom JAR you have
          mvn install:install-file -Dfile=lib/your-custom-library.jar -DgroupId=com.yourteam -DartifactId=your-custom-library -Dversion=1.0.0 -Dpackaging=jar -DgeneratePom=true
      - name: Build with Maven
        run: mvn -B package --file pom.xml

• Use Approach 1 if you have a small number of JARs and want minimal CI script changes. Just be mindful of the packaging setup.
• Use Approach 2 for longer-term projects or multiple custom JARs—it follows Maven's best practices and avoids the edge cases of system scope dependencies.

内容的提问来源于stack exchange，提问作者Mayank Gupta