Maven多模块项目导入模块

Question

I read a lot of tutorials for the last 3 days with no success.

I have a maven multi module project. In the parent pom I define my submodules:

  ...
  <groupId>test</groupId>
  <artifactId>parent</artifactId>
  <version>0.0.1-SNAPSHOT</version>
  <name>parent</name>
  <packaging>pom</packaging>
  <modules>
   <module>common</module>
   <module>backend</module>
  </modules>

The common module keeps common data. Basically it provides google protobuf classes that will be used in my backend (and later also client) project. So, my protobufs are being generated and now I want to use them in my backend project.

pom.xml common:

<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>
  <parent>
    <groupId>test</groupId>
    <artifactId>parent</artifactId>
    <version>0.0.1-SNAPSHOT</version>
  </parent>
  <artifactId>common</artifactId>
  <name>common</name>
  <packaging>jar</packaging>
  <dependencies>
   <dependency>
      <groupId>com.google.protobuf</groupId>
      <artifactId>protobuf-java</artifactId>
      <version>2.6.1</version>
   </dependency>
  </dependencies>
  <build>
  <plugins>
  <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.5.1</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.xolstice.maven.plugins</groupId>
        <artifactId>protobuf-maven-plugin</artifactId>
        <version>0.5.0</version>
        <configuration>
          <protocExecutable>protoc</protocExecutable>
        </configuration>
        <executions>
          <execution>
            <goals>
              <goal>compile</goal>
              <goal>test-compile</goal>
            </goals>
          </execution>
        </executions>
      </plugin>
  </plugins>
  </build>
</project>

pom.xml backend: In the dependencies section I define the common project to be included.

    <?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>test</groupId>
    <artifactId>parent</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    </parent>
    <artifactId>backend</artifactId>
    <name>backend</name>
    <packaging>jar</packaging>
    <properties>
    <jersey.version>2.22.2</jersey.version>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencyManagement>
    <dependencies>
      <dependency>
        <groupId>test</groupId>
        <artifactId>common</artifactId>
        <version>${project.parent.version}</version>
      </dependency>
      <dependency>
        <groupId>org.glassfish.jersey</groupId>
        <artifactId>jersey-bom</artifactId>
        <version>${jersey.version}</version>
        <type>pom</type>
        <scope>import</scope>
      </dependency>
    </dependencies>
   </dependencyManagement>
   <dependencies>
    <dependency>
      <groupId>org.glassfish.jersey.containers</groupId>
      <artifactId>jersey-container-grizzly2-http</artifactId>
    </dependency>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.9</version>
      <scope>test</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>2.5.1</version>
        <inherited>true</inherited>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
      <plugin>
        <groupId>org.codehaus.mojo</groupId>
        <artifactId>exec-maven-plugin</artifactId>
        <version>1.2.1</version>
        <executions>
          <execution>
            <goals>
              <goal>java</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
          <mainClass>backend.Main</mainClass>
        </configuration>
      </plugin>
      <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-assembly-plugin</artifactId>
                <configuration>
                    <descriptorRefs>
                        <descriptorRef>jar-with-dependencies</descriptorRef>
                    </descriptorRefs>
                    <finalName>jersey-service-${project.version}</finalName>
                    <archive>
                        <manifest>                           <mainClass>de.unidue.inf.is.websail.wsbackend.Main</mainClass>
                        </manifest>
                    </archive>
                </configuration>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>single</goal>
                        </goals>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-dependency-plugin</artifactId>
                <version>2.4</version>
                <executions>
                    <execution>
                        <id>copy-dependencies</id>
                        <phase>package</phase>
                        <goals><goal>copy-dependencies</goal></goals>
                    </execution>
                </executions>
            </plugin>
        </plugins>
      </build>
    </project>

Now, I am using mvn install on the parent project to generate and copy the jars to my local repository. (I also tried to invoke the command on the common project first). Everything is being generated fine but I can not use my protobufs and other classes in backend module..

The dependency tree of the backend module does not even show up my "test.common" dependency. Thats why I can not include the classes. Its very frustrating! I tried a lot, eg, to use the maven compiler plugin in my common pom:

    <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-dependency-plugin</artifactId>
        <version>2.4</version>
        <executions>
            <execution>
                <id>copy-dependencies</id>
                <phase>package</phase>
                <goals><goal>copy-dependencies</goal></goals>
            </execution>
        </executions>
    </plugin>

But it stills does not work. Do I miss anything? When looking to my local repository I can see the "test.common" jar but the backend module does not import it. Hope you can help me.

* UPDATE *

Moving common dependency to dependencies section:

  <dependencies>
    ...
    <dependency>
        <groupId>test</groupId>
        <artifactId>common</artifactId>
        <version>${project.parent.version}</version>
        <scope>compile</scope>
    </dependency>
  </dependencies>

Best regards Ioannis K.

Answer 1

Oh my gosh! I didnt realize I put the common dependency to the dependencyManagement section.

To solve the problem: move the common dependency from dependencyManagement to dependencies section.

Best regards Ioannis K.