maven 是常用的jar包管理工具之一。在引入的jar包多了之后往往会有同一个jar包的不同版本都被引入的情况， 这个时候需要将不用的jar包进行排除。 虽然可以使用mvn dependency:tree 来查看所有引入的jar包， 但要从中找出哪些jar包有多个版本往往很困难。 下面介绍一个maven plugin 可以帮助我们快速找出哪些java类重复了。
duplicate-finder-maven-plugin 引入
<build>
<plugins>
<plugin>
<groupId>org.basepom.maven</groupId>
<artifactId>duplicate-finder-maven-plugin</artifactId>
<version>1.1.0</version>
<executions>
<execution>
<id>default</id>
<phase>verify</phase>
<goals>
<goal>check</goal>
</goals>
</execution>
</executions>
<configuration>
<skip>false</skip>
<quiet>false</quiet>
<checkCompileClasspath>true</checkCompileClasspath>
<checkRuntimeClasspath>true</checkRuntimeClasspath>
<checkTestClasspath>true</checkTestClasspath>
<failBuildInCaseOfDifferentContentConflict>false</failBuildInCaseOfDifferentContentConflict>
<failBuildInCaseOfEqualContentConflict>false</failBuildInCaseOfEqualContentConflict>
<failBuildInCaseOfConflict>false</failBuildInCaseOfConflict>
<printEqualFiles>false</printEqualFiles>
<preferLocal>true</preferLocal>
<!-- Version 1.1.1+ -->
<includeBootClasspath>false</includeBootClasspath>
<bootClasspathProperty>sun.boot.class.path</bootClasspathProperty>
<!-- Version 1.1.1+ -->
<!-- Version 1.2.0+ -->
<includePomProjects>false</includePomProjects>
<!-- Version 1.2.0+ -->
</configuration>
</plugin>
</plugins>
</build>
duplicate-finder-maven-plugin 执行
mvn duplicate-finder:check
输出example
[WARNING] Found duplicate and different classes in [com.alibaba.external:misc.javassist:3.9.0.GA, org.javassist:javassist:3.18.0-GA]:
[WARNING] javassist.ByteArrayClassPath
[WARNING] javassist.CannotCompileException
[WARNING] javassist.ClassClassPath
[WARNING] javassist.ClassMap
[WARNING] javassist.ClassPath
[WARNING] javassist.ClassPathList
....
