Java study notes-exclude pom dependency

We know that the introduction of dependencies in maven, directly in the pom file

 <dependency>
      <groupId>ch.qos.logback</groupId>
      <artifactId>logback-classic</artifactId>
      <version>1.2.1</version>
 </dependency>

 

But sometimes the imported dependency contains a layer of dependency, and the layer of dependency in it is not what we want, it needs to be excluded, how can we exclude it?

<dependency>
     <groupId>com.taobao.metaq.final</groupId>
     <artifactId>metaq-client</artifactId>
     <version>4.1.6.Final</version>
     <exclusions>
           <exclusion>
               <groupId>com.alibaba.unit.rule</groupId>
               <artifactId>unitrouter</artifactId>
           </exclusion>
      </exclusions>
 </dependency>

It can be seen from the above example that <exclusions><exclusion><exclusion/></exclusions> is used for exclusion, and the only dependency on the positioning of exclusion is groups and artifactId

At this time, you can introduce other versions of the dependency or not