如何从maven中的其他库继承依赖项？

Question

I created a custom my-commons library with maven. The commons pom contains eg the following dependency:

<?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">

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.4.RELEASE</version>
        <relativePath/>
    </parent>

    <groupId>de.mydomain</groupId>
    <artifactId>my-commons</artifactId>
    <version>1.0.0</version>
    <packaging>jar</packaging> 

    <properties>
        <!-- workaround for http://jira.codehaus.org/browse/MASSEMBLY-603-->
        <maven.build.timestamp>${maven.build.timestamp}</maven.build.timestamp>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
    </dependencies>
</project>

I installed the custom library into my local repository. In a different project, I reuse the library. It resolves correctly, so it exists in the repo:

<project ...>
    <groupId>de.mydomain</groupId>
    <artifactId>my-core</artifactId>
    <version>1.0.0</version>

    <dependencies>
        <dependency>
            <groupId>my.domain</groupId>
            <artifactId>my-commons</artifactId>
            <version>1.0.0</version>
        </dependency>
    </dependencies>
</project>

Now in this project I'd like to use a class org.springframework.web.bind.annotation.ResponseBody .

Problem: the class is not in classpath. So maven complains [ERROR] cannot find symbol . But why?? I'd expect the dependency being inherited!

Sidenote: I'm using Intellij IDEA if that matters. The same problem applies to all "inherited" libraries. The spring-web lib is just an example.

Answer 1

Please check if .m2 folder contains the jar you want to use or not. You can use mvn install command in commons project to generate the jar. Also you need to add commons project in your project pom that you are running.

Answer 2

You need to create the artifact for your commons project, through its pom.xml.

Like in my below example i created a separate project where i am using the AWS and some other dependency and then final jar, which i am using in other project :-

My AWS-client pom.xml looks like below :-

<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.kaamkaj</groupId>
    <artifactId>aws-clients</artifactId>
    <version>1.0-SNAPSHOT</version>

    <packaging>jar</packaging>

    <name>aws-clients</name>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <aws.sdk.version>1.11.104</aws.sdk.version>
    </properties>



    <dependencies>
        <!--AWS dependency-->
        <!-- https://mvnrepository.com/artifact/com.amazonaws/aws-java-sdk-dynamodb -->
        <dependency>
            <groupId>com.amazonaws</groupId>
            <artifactId>aws-java-sdk-dynamodb</artifactId>
            <version>${aws.sdk.version}</version>
        </dependency>
        <dependency>
            <groupId>com.mercadopago</groupId>
            <artifactId>sdk</artifactId>
            <version>0.3.4</version>
        </dependency>
    </dependencies>

    <repositories>
        <repository>
            <id>mercadopago</id>
            <url>https://github.com/mercadopago/sdk-java/raw/master/releases</url>
        </repository>
    </repositories>

</project>

Also, run mvn clean install on the commons pom, in your case.

And then in all other project where i need to include the aws-client , i use the artifact-id of above project, like below :-

 <dependency>
            <groupId>com.kaamkaj</groupId>
            <artifactId>aws-clients</artifactId>
            <version>1.0-SNAPSHOT</version>
        </dependency>

Let me know if you have any questions:

Answer 3

Found it: removing the <maven.build.timestamp>... <property> solved the problem. I don't know why it prevented the inheritance to work properly, especially as I didn't get any errors.