通过enforcer插件定位jar包或类冲突问题

jar包或者类冲突，一般日志中出现类似于： 

Java.lang.NoClassDefFoundError，java.lang.NoSuchMethodError，java.lang.NoSuchFieldError，java.lang.NoSuchMethodException，java.lang.LinkageError，java.lang.ClassNotFoundException

 

首先在maven插件中添加enforcer插件：

<plugin>

    <groupId>org.apache.maven.plugins</groupId>

    <artifactId>maven-enforcer-plugin</artifactId>

    <version>1.4.1</version>

    <executions>

        <execution>

            <id>default-cli</id>

            <phase>validate</phase>

            <goals>

                <goal>enforce</goal>

            </goals>

        </execution>

    </executions>

    <dependencies>

        <dependency>

            <groupId>org.codehaus.mojo</groupId>

            <artifactId>extra-enforcer-rules</artifactId>

            <version>1.0-beta-4</version>

        </dependency>

    </dependencies>

    <configuration>

        <!--规则检查不通过就构建失败;Default:false. -->

        <!--<failFast>true</failFast>-->

        <rules>

            <!--<requireMavenVersion>

                <version>3.0.4</version>

            </requireMavenVersion>-->

            <requireJavaVersion>

                <version>1.6.0</version>

            </requireJavaVersion>

            <banDuplicateClasses>

                <ignoreClasses>

                    <ignoreClass>javax.*</ignoreClass>

                    <ignoreClass>org.junit.*</ignoreClass>

                    <ignoreClass>junit.*</ignoreClass>

                    <ignoreClass>org.apache.xbean.recipe.*</ignoreClass>

                    <ignoreClass>org.hamcrest.*</ignoreClass>

                    <ignoreClass>org.slf4j.*</ignoreClass>

                    <ignoreClass>org.antlr.runtime.*</ignoreClass>

                    <ignoreClass>org.apache.commons.lang.*</ignoreClass>

                    <ignoreClass>org.apache.commons.codec.*</ignoreClass>

                    <ignoreClass>org.apache.commons.logging.*</ignoreClass>

                    <ignoreClass>org.codehaus.plexus.component.builder.*</ignoreClass>

                </ignoreClasses>

                <findAllDuplicates>true</findAllDuplicates>

            </banDuplicateClasses>

            <bannedDependencies>

                <!--是否检查传递性依赖(间接依赖)-->

                <searchTransitive>true</searchTransitive>

                <excludes>

                    <exclude>org.apache:libthrift</exclude>

                    <exclude>org.jboss.netty:netty</exclude>

                    <exclude>org.apache.thrift:libthrift:(,0.8.0),(0.8.0,)</exclude>

                    <exclude>io.netty:netty:(,3.9.2.Final)</exclude>

                    <exclude>com.sankuai.octo:mns-invoker:(,1.7.5)</exclude>

                    <exclude>com.fasterxml.jackson.core:*:(,2.6.0)</exclude>

                    <exclude>com.google.guava:guava:(,15.0)</exclude>

                    <exclude>com.caucho:hessian:(,3.1.5),(3.1.5,)</exclude>

                    <exclude>com.dianping.dpsf:dpsf-net:(,2.9.7)</exclude>

                    <exclude>com.dianping:pigeon-octo:(,0.1.1)</exclude>

                    <exclude>com.dianping.platform:platform-sdk:(,1.3.5)</exclude>

                    <exclude>com.dianping.lion:lion-client:(,0.6.7)</exclude>

                    <exclude>com.dianping.cat:*:(,1.5.4)</exclude>

                    <exclude>com.dianping.swallow:swallow-producerclient:(,0.8.7)</exclude>

                    <exclude>com.dianping.swallow:swallow-consumerclient:(,0.8.7)</exclude>

                    <exclude>com.dianping.swallow:swallow-common:(,0.8.7)</exclude>

                    <exclude>com.dianping.swallow:swallow-client:(,0.5.4)</exclude>

                </excludes>

                <message>some dependency must exclude</message>

            </bannedDependencies>

        </rules>

    </configuration>

</plugin>

 

然后输入maven命令来查找重复类和存在版本限制和冲突的jar包：

mvn -U clean package -Dmaven.test.skip=true enforcer:enforce -DcheckDeployRelease_skip=true

会看到相关的输出，一个个排查即可：

存在重复的类的情况：

Found in:

    org.jboss.netty:netty:jar:3.2.19:compile

    io.netty:netty:jar:3.9.2.Final:compile

  Duplicate classes:

    org/jboss/netty/handler/codec/base64/Base64Decoder.class

    org/jboss/netty/util/VirtualExecutorService.class

以下省略

不允许的依赖jar包或不允许的依赖版本号：

[WARNING] Rule 2: org.apache.maven.plugins.enforcer.BannedDependencies failed with message:

some dependency must exclude

Found Banned Dependency: org.apache:libthrift:jar:0.6.0

Found Banned Dependency: org.jboss.netty:netty:jar:3.2.19

Found Banned Dependency: org.apache.thrift:libthrift:jar:0.9.3

Use 'mvn dependency:tree' to locate the source of the banned dependencies.

最后根据插件排查下来的信息，一个个排除掉存在冲突的jar包即可。注意如果是parent pom当中的依赖冲突，要在parent pom中修改，否则无法排除。

福利：使用idea的同学，推荐使用maven helper插件排除冲突，一目了然，很好用。

enforcer插件参考文档：

http://www.tuicool.com/articles/RfIBfa

https://github.com/dimitri-koussa/maven-enforcer-duplicate-class-check

http://www.mojohaus.org/extra-enforcer-rules/banDuplicateClasses.html