學習Maven之MavenEnforcerPlugin

2019-11-14 15:35:07

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1.Maven Enforcer plugin是什么鬼？

在說這個插件是什么前我們先思考這么一個問題：當我們開發人員進入項目組進行開發前，要準備開發環境，而領導總是會強調工具的統一，編譯環境的統一。比如要求所有開發人員使用JDK1.8進行開發。

開發人員接下來就是去下載指定版本的JDK，然后開始開發。但是如果開發人員的機器配置比較多，有好幾個版本的JDK，而他雖然下載了JDK1.8，但是忘記配置環境變量，很有可能他用了JDK1.6進行的編譯。

問題有了，該如何解決？ Maven Enforcer plugin就是來解決這類問題。Enforcer可以在項目validate時，對項目環境進行檢查。

2.Maven Enforcer plugin怎么用？

Enforcer配置后默認會在validate后執行enforcer:enforce,然后對項目環境進行檢查。拿上面對JDK的校驗為例，我們在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>

我本地配置沒有JDK1.8，按照我的期望，執行maven命令時應該會失敗。讓我們來執行命令 mvn validate 會打出如下日志告知我們JDK版本過低。

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

其實執行命令 mvn enforcer:enforce 也可以達到上面的效果。區別就是validate是maven全局命令，enforcer:enforce是只執行這個插件的命令。

這里要注意一點，執行enforcer:enforce時，id必須是default-cli（具體原因請參閱:http://stackoverflow.com/questions/24827194/maven-enforcer-plugin-missing-or-invalid-rules）,否則會報

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

3.Maven Enforcer plugin標簽詳解

現在對這個插件的配置講解一下。

<plugin><artifactId>maven-enforcer-plugin</artifactId><version>1.4.1</version><executions>  <execution>    <id>default-cli</id>         －－一個執行實例的id      <goals>        <goal>enforce</goal>     －－執行的命令      </goals>      <phase>validate</phase>    －－執行的階段      <configuration>        <rules>                  －－規則          <requireJavaVersion>   －－JDK的版本            <message>            －－失敗后提示消息              <![CDATA[You are running an older version of Java. This application requires at least JDK ${java.version}.]]>             </message>             <version>[${java.version}.0,)</version>   －－JDK版本規則           </requireJavaVersion>         </rules>       </configuration>    </execution>  </executions></plugin>

Enforcer的rules除了控制JDK版本，還有很多其他規則，甚至可以通過它的接口自定義。

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.

我們再寫一個例子。比如除了需要限制JDK外，我們還要限定maven版本，項目不得包含TestNG依賴，操作系統必須是mac os x 64位,項目版本號在執行install時必須是正式版本。

直接上代碼：

<?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>                                    <!--是否檢查傳遞性依賴(間接依賴)-->                                    <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>        ...        <!--測試放開-->        <!--<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>