学习Maven之MavenEnforcerPlugin

2019-11-14 15:35:07

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1.Maven Enforcer plugin是什么鬼？

在说这个插件是什么前我们先思考这么一个问题：当我们开发人员进入项目组进行开发前，要准备开发环境，而领导总是会强调工具的统一，编译环境的统一。比如要求所有开发人员使用JDK1.8进行开发。

开发人员接下来就是去下载指定版本的JDK，然后开始开发。但是如果开发人员的机器配置比较多，有好几个版本的JDK，而他虽然下载了JDK1.8，但是忘记配置环境变量，很有可能他用了JDK1.6进行的编译。

问题有了，该如何解决？ Maven Enforcer plugin就是来解决这类问题。Enforcer可以在项目validate时，对项目环境进行检查。

2.Maven Enforcer plugin怎么用？

Enforcer配置后默认会在validate后执行enforcer:enforce,然后对项目环境进行检查。拿上面对JDK的校验为例，我们在pom.xml中配置插件。

<?xml version="1.0" encoding="UTF-8"?><PRoject>...    <build>        <plugins>            <plugin>                <artifactId>maven-enforcer-plugin</artifactId>                <version>1.4.1</version>                <executions>                    <execution>                        <id>default-cli</id>                        <goals>                            <goal>enforce</goal>                        </goals>                        <phase>validate</phase>                        <configuration>                            <rules>                                <requirejavaVersion>                                    <message>                                        <![CDATA[You are running an older version of Java. This application requires at least JDK ${java.version}.]]>                                    </message>                                    <version>[${java.version}.0,)</version>                                </requireJavaVersion>                            </rules>                        </configuration>                    </execution>                </executions>            </plugin>        </plugins>    </build>    <properties>        <java.version>1.8</java.version>    </properties> </project>

我本地配置没有JDK1.8，按照我的期望，执行maven命令时应该会失败。让我们来执行命令 mvn validate 会打出如下日志告知我们JDK版本过低。

qyfmac$ mvn validate[INFO] Scanning for projects...[INFO] ------------------------------------------------------------------------[INFO] Reactor Build Order:[INFO] [INFO] AppFuse Modular Application[INFO] AppFuse Modular Application - Core[INFO] AppFuse Modular Application - Web (Spring MVC)[INFO]                                                                         [INFO] ------------------------------------------------------------------------[INFO] Building AppFuse Modular Application 1.0-SNAPSHOT[INFO] ------------------------------------------------------------------------[INFO] [INFO] --- maven-enforcer-plugin:1.4.1:enforce (enforce-versions) @ stock ---[WARNING] Rule 1: org.apache.maven.plugins.enforcer.RequireJavaVersion failed with message:You are running an older version of Java. This application requires at least JDK 1.8.[INFO] ------------------------------------------------------------------------[INFO] Reactor Summary:[INFO] [INFO] AppFuse Modular Application ........................ FAILURE [  0.987 s][INFO] AppFuse Modular Application - Core ................. SKipPED[INFO] AppFuse Modular Application - Web (Spring MVC) ..... SKIPPED[INFO] ------------------------------------------------------------------------[INFO] BUILD FAILURE[INFO] ------------------------------------------------------------------------[INFO] Total time: 1.886 s[INFO] Finished at: 2015-09-22T15:37:04+08:00[INFO] Final Memory: 16M/156M[INFO] ------------------------------------------------------------------------[ERROR] Failed to execute goal org.apache.maven.plugins:maven-enforcer-plugin:1.4.1:enforce (enforce-versions) on project stock: Some Enforcer rules have failed. Look above for specific messages explaining why the rule failed. -> [Help 1][ERROR] [ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.[ERROR] Re-run Maven using the -X switch to enable full debug logging.[ERROR] [ERROR] For more information about the errors and possible solutions, please read the following articles:[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/MojoExecutionException

其实执行命令 mvn enforcer:enforce 也可以达到上面的效果。区别就是validate是maven全局命令，enforcer:enforce是只执行这个插件的命令。

这里要注意一点，执行enforcer:enforce时，id必须是default-cli（具体原因请参阅:http://stackoverflow.com/questions/24827194/maven-enforcer-plugin-missing-or-invalid-rules）,否则会报

The parameters 'rules' for goal org.apache.maven.plugins:maven-enforcer-plugin:1.4.1:enforce are missing or invalid

3.Maven Enforcer plugin标签详解

现在对这个插件的配置讲解一下。

<plugin><artifactId>maven-enforcer-plugin</artifactId><version>1.4.1</version><executions>  <execution>    <id>default-cli</id>         －－一个执行实例的id      <goals>        <goal>enforce</goal>     －－执行的命令      </goals>      <phase>validate</phase>    －－执行的阶段      <configuration>        <rules>                  －－规则          <requireJavaVersion>   －－JDK的版本            <message>            －－失败后提示消息              <![CDATA[You are running an older version of Java. This application requires at least JDK ${java.version}.]]>             </message>             <version>[${java.version}.0,)</version>   －－JDK版本规则           </requireJavaVersion>         </rules>       </configuration>    </execution>  </executions></plugin>

Enforcer的rules除了控制JDK版本，还有很多其他规则，甚至可以通过它的接口自定义。

alwaysFail - Always fail... used to test plugin configuration.
alwaysPass - Always passes... used to test plugin configuration.
banDistributionManagement - enforces that project doesn't have distributionManagement.
bannedDependencies - enforces that excluded dependencies aren't included.
bannedPlugins - enforces that specific plugins aren't included in the build.
bannedRepositories - enforces to not include banned repositories.
banTransitiveDependencies - enforces that project doesn't have transitive dependencies.
dependencyConvergence - ensure all dependencies converge to the same version.
evaluateBeanshell - evaluates a beanshell script.
reactorModuleConvergence - enforces that a multi module build follows best practice.
requireActiveProfile - enforces one or more active profiles.
requireEnvironmentVariable - enforces the existence of an environment variable
requireFilesDontExist - enforces that the list of files does not exist.
requireFilesExist - enforces that the list of files does exist.
requireFilesSize - enforces that the list of files exists and is within a certain size range.
requireJavaVersion - enforces the JDK version.
requireMavenVersion - enforces the Maven version.
requireNoRepositories - enforces to not include repositories.
requireOS - enforces the OS / CPU Architecture.
requirePluginVersions - enforces that all plugins have a specified version.
requirePrerequisite - enforces that prerequisites have been specified.
requireProperty - enforces the existence and values of properties.
requireReleaseDeps - enforces that no snapshots are included as dependencies.
requireReleaseVersion - enforces that the artifact is not a snapshot.
requireSameVersions - enforces that specific dependencies and/or plugins have the same version.
requireUpperBoundDeps - ensures that every (transitive) dependency is resolved to it's specified version or higher.

You may also create and inject your own custom rules by following the maven-enforcer-rule-api instructions.

我们再写一个例子。比如除了需要限制JDK外，我们还要限定maven版本，项目不得包含TestNG依赖，操作系统必须是mac os x 64位,项目版本号在执行install时必须是正式版本。

直接上代码：

<?xml version="1.0" encoding="UTF-8"?><project>...    <build>        <plugins>            <plugin>                <artifactId>maven-enforcer-plugin</artifactId>                <version>1.4.1</version>                <executions>                    <execution>                        <id>default-cli</id>                        <goals>                            <goal>display-info</goal>                            <goal>enforce</goal>                        </goals>                        <phase>validate</phase>                        <configuration>                            <rules>                                <requireMavenVersion>                                    <message>                                        <![CDATA[You are running an older version of Maven. This application requires at least Maven ${maven.version}.]]>                                    </message>                                    <version>[${maven.version},)</version>                                </requireMavenVersion>                                <requireJavaVersion>                                    <message>                                        <![CDATA[You are running an older version of Java. This application requires at least JDK ${java.version}.]]>                                    </message>                                    <version>[${java.version}.0,)</version>                                </requireJavaVersion>                                <bannedDependencies>                                    <!--是否检查传递性依赖(间接依赖)-->                                    <searchTransitive>true</searchTransitive>                                    <excludes>                                        <!--groupId[:artifactId][:version][:type][:scope][:classifier]--> 
                                        <exclude>org.testng:testng</exclude>                                    </excludes>                                    <message>don't use TestNG,must use JUnit</message>                                </bannedDependencies>                                <requireOS>                                    <name>mac os x</name>                                    <family>mac</family>                                    <arch>x86_64</arch>                                    <version>10.10.3</version>                                </requireOS>                                <requireProperty>                                    <property>project.version</property>                                    <message>"Project version must be specified."</message>                                    <regex>.*(/d|-SNAPSHOT)$</regex>                                    <regexMessage>"Project version must end in a number or -SNAPSHOT."</regexMessage>                                </requireProperty>                            </rules>                        </configuration>                    </execution>                    <execution>                        <id>enforce-install</id>                        <goals>                            <goal>enforce</goal>                        </goals>                        <phase>install</phase>                        <configuration>                            <rules>                                <requireProperty>                                    <property>project.version</property>                                    <message>"Project version must be specified."</message>                                    <regex>.*(/d)$</regex>                                    <regexMessage>"Project version must end in a number."</regexMessage>                                </requireProperty>                            </rules>                        </configuration>                    </execution>                </executions>            </plugin>        </plugins>    </build>    <dependencies>        ...        <!--测试放开-->        <!--<dependency>-->            <!--<groupId>org.testng</groupId>-->            <!--<artifactId>testng</artifactId>-->            <!--<version>6.1.1</version>-->            <!--<scope>test</scope>-->        <!--</dependency>-->    </dependencies>    <properties>        <java.version>1.7</java.version>        <maven.version>3.3.3</maven.version>    </properties></project>