【Maven】查看插件配置参数

ゞ浴缸里的玫瑰 2023-10-14 09:46 4阅读 0赞

#### 目录 ####

*  背景
 *  帮助命令
 *  使用举例
 *  查看详细信息
 *  查看指定目标
 *  其他命令

## 背景 ##

工作中使用到很多的`Maven`插件，虽然可以从网上拷贝别人的配置来用，但是想要深入了解一个插件一共有哪些可用的配置参数，就无从下手了。

当然可以从插件的官方网站查看帮助手册，也可以通过`Maven`的`help`命令查看插件帮助，包括插件的简略和详细的描述信息，也可以查看插件所有的目标`goal`，以及插件的配置参数等。

## 帮助命令 ##

在命令行下面，使用`Maven`的`help:describe`目标查看插件信息：`mvn help:describe -Dplugin=插件标识`

>  *  通过plugin参数指定要查看的插件，插件标识可以是groupId:artifactId\[:version\]形式的，
>  *  其中version是可选的，
>  *  也可以是插件前缀，
>  *  它是插件的简称，
>  *  插件前缀和插件是一一对应的，
>  *  这种对应关系存储在Maven仓库元数据中：`https://repo.maven.apache.org/maven2/org/apache/maven/plugins/maven-metadata.xml`
>  *  比如插件前缀help和插件maven-help-plugin是对应的

<plugin>
      <name>Apache Maven Help Plugin</name>
      <prefix>help</prefix>
      <artifactId>maven-help-plugin</artifactId>
    </plugin>

## 使用举例 ##

下面查看`maven-help-plugin`插件的信息，即查看帮助命令自己的信息，下面两条命令是等价的：

mvn help:describe -Dplugin=org.apache.maven.plugins:maven-help-plugin
    mvn help:describe -Dplugin=help

输出查询结果如下

可以看到`maven-help-plugin`对应的插件前缀是`help`

Group Id: org.apache.maven.plugins
    Artifact Id: maven-help-plugin
    Version: 3.2.0
    Goal Prefix: help

可以看到`help:describe`用来查看插件的属性和目标

help:describe
      Description: Displays a list of the attributes for a Maven Plugin and/or
        goals (aka Mojo - Maven plain Old Java Object).

>  *  可以看到help命令自带的帮助: `mvn help:help`
>  *  输出的结果基本和上面的相同
>  *  这里更推荐使用help:describe命令

## 查看详细信息 ##

通过在命令后追加`-Ddetail`参数，可以查看插件的详细信息：

简略信息：
    mvn help:describe -Dplugin=help
    详细信息：
    mvn help:describe -Dplugin=help -Ddetail

详细信息输出如下,这是可以看到每个`goal`的配置参数说明

[INFO] Scanning for projects...
    [INFO]
    [INFO] ------------------< org.apache.maven:standalone-pom >-------------------
    [INFO] Building Maven Stub Project (No POM) 1
    [INFO] --------------------------------[ pom ]---------------------------------
    [INFO]
    [INFO] --- maven-help-plugin:3.2.0:describe (default-cli) @ standalone-pom ---
    [INFO] org.apache.maven.plugins:maven-help-plugin:3.2.0
     
    Name: Apache Maven Help Plugin
    Description: The Maven Help plugin provides goals aimed at helping to make
      sense out of the build environment. It includes the ability to view the
      effective POM and settings files, after inheritance and active profiles have
      been applied, as well as a describe a particular plugin goal to give usage
      information.
    Group Id: org.apache.maven.plugins
    Artifact Id: maven-help-plugin
    Version: 3.2.0
    Goal Prefix: help
     
    This plugin has 8 goals:
     
    help:active-profiles
      Description: Displays a list of the profiles which are currently active for
        this build.
      Implementation: org.apache.maven.plugins.help.ActiveProfilesMojo
      Language: java
     
      Available parameters:
     
        output
          User property: output
          Optional parameter to write the output of this help in a given file,
          instead of writing to the console.
          Note: Could be a relative path.
     
    help:all-profiles
      Description: Displays a list of available profiles under the current
        project.
        Note: it will list all profiles for a project. If a profile comes up with a
        status inactive then there might be a need to set profile activation
        switches/property.
      Implementation: org.apache.maven.plugins.help.AllProfilesMojo
      Language: java
     
      Available parameters:
     
        output
          User property: output
          Optional parameter to write the output of this help in a given file,
          instead of writing to the console.
          Note: Could be a relative path.
     
    help:describe
      Description: Displays a list of the attributes for a Maven Plugin and/or
        goals (aka Mojo - Maven plain Old Java Object).
      Implementation: org.apache.maven.plugins.help.DescribeMojo
      Language: java
     
      Available parameters:
     
        artifactId
          User property: artifactId
          The Maven Plugin artifactId to describe.
          Note: Should be used with groupId parameter.
     
        cmd
          User property: cmd
          A Maven command like a single goal or a single phase following the Maven
          command line:
          mvn [options] [<goal(s)>] [<phase(s)>]
     
        detail (Default: false)
          User property: detail
          This flag specifies that a detailed (verbose) list of goal (Mojo)
          information should be given.
     
        goal
          User property: goal
          The goal name of a Mojo to describe within the specified Maven Plugin. If
          this parameter is specified, only the corresponding goal (Mojo) will be
          described, rather than the whole Plugin.
     
        groupId
          User property: groupId
          The Maven Plugin groupId to describe.
          Note: Should be used with artifactId parameter.
     
        minimal (Default: false)
          User property: minimal
          This flag specifies that a minimal list of goal (Mojo) information should
          be given.
     
        output
          User property: output
          Optional parameter to write the output of this help in a given file,
          instead of writing to the console.
          Note: Could be a relative path.
     
        plugin
          Alias: prefix
          User property: plugin
          The Maven Plugin to describe. This must be specified in one of three
          ways:
     
          1.  plugin-prefix, i.e. 'help'
          2.  groupId:artifactId, i.e. 'org.apache.maven.plugins:maven-help-plugin'
          3.  groupId:artifactId:version, i.e.
            'org.apache.maven.plugins:maven-help-plugin:2.0'
     
        version
          User property: version
          The Maven Plugin version to describe.
          Note: Should be used with groupId/artifactId parameters.
     
    help:effective-pom
      Description: Displays the effective POM as an XML for this build, with the
        active profiles factored in, or a specified artifact. If verbose, a comment
        is added to each XML element describing the origin of the line.
      Implementation: org.apache.maven.plugins.help.EffectivePomMojo
      Language: java
     
      Available parameters:
     
        artifact
          User property: artifact
          The artifact for which to display the effective POM.
          Note: Should respect the Maven format, i.e. groupId:artifactId[:version].
          The latest version of the artifact will be used when no version is
          specified.
     
        output
          User property: output
          Optional parameter to write the output of this help in a given file,
          instead of writing to the console.
          Note: Could be a relative path.
     
        verbose (Default: false)
          User property: verbose
          Output POM input location as comments.
     
    help:effective-settings
      Description: Displays the calculated settings as XML for this project,
        given any profile enhancement and the inheritance of the global settings
        into the user-level settings.
      Implementation: org.apache.maven.plugins.help.EffectiveSettingsMojo
      Language: java
     
      Available parameters:
     
        output
          User property: output
          Optional parameter to write the output of this help in a given file,
          instead of writing to the console.
          Note: Could be a relative path.
     
        showPasswords (Default: false)
          User property: showPasswords
          For security reasons, all passwords are hidden by default. Set this to
          true to show all passwords.
     
    help:evaluate
      Description: Evaluates Maven expressions given by the user in an
        interactive mode.
      Implementation: org.apache.maven.plugins.help.EvaluateMojo
      Language: java
     
      Available parameters:
     
        artifact
          User property: artifact
          An artifact for evaluating Maven expressions.
          Note: Should respect the Maven format, i.e. groupId:artifactId[:version].
          The latest version of the artifact will be used when no version is
          specified.
     
        expression
          User property: expression
          An expression to evaluate instead of prompting. Note that this must not
          include the surrounding ${...}.
     
        forceStdout (Default: false)
          User property: forceStdout
          This options gives the option to output information in cases where the
          output has been suppressed by using -q (quiet option) in Maven. This is
          useful if you like to use maven-help-plugin:evaluate in a script call
          (for example in bash) like this:
          RESULT=$(mvn help:evaluate -Dexpression=project.version -q -DforceStdout)
          echo $RESULT
          This will only printout the information which has been requested by
          expression to stdout.
     
        output
          User property: output
          Optional parameter to write the output of this help in a given file,
          instead of writing to the console. This parameter will be ignored if no
          expression is specified.
          Note: Could be a relative path.
     
    help:help
      Description: Display help information on maven-help-plugin.
        Call mvn help:help -Ddetail=true -Dgoal=<goal-name> to display parameter
        details.
      Implementation: org.apache.maven.plugins.help.HelpMojo
      Language: java
     
      Available parameters:
     
        detail (Default: false)
          User property: detail
          If true, display all settable properties for each goal.
     
        goal
          User property: goal
          The name of the goal for which to show help. If unspecified, all goals
          will be displayed.
     
        indentSize (Default: 2)
          User property: indentSize
          The number of spaces per indentation level, should be positive.
     
        lineLength (Default: 80)
          User property: lineLength
          The maximum length of a display line, should be positive.
     
    help:system
      Description: Displays a list of the platform details like system properties
        and environment variables.
      Implementation: org.apache.maven.plugins.help.SystemMojo
      Language: java
     
      Available parameters:
     
        output
          User property: output
          Optional parameter to write the output of this help in a given file,
          instead of writing to the console.
          Note: Could be a relative path.
     
     
    [INFO] ------------------------------------------------------------------------
    [INFO] BUILD SUCCESS
    [INFO] ------------------------------------------------------------------------
    [INFO] Total time:  1.904 s
    [INFO] Finished at: 2021-10-12T15:53:53+08:00
    [INFO] ------------------------------------------------------------------------

## 查看指定目标 ##

可以通过`-Dgoal`参数，查看指定目标的详细信息：

简略信息：
    mvn help:describe -Dplugin=help -Dgoal=describe
    详细信息：
    mvn help:describe -Dplugin=help -Dgoal=describe -Ddetail

简略信息输出如下

详细信息输出如下

## 其他命令 ##

该帮助插件还有很多有用的`goal`，下面仅列出几个常用的，更多的请自行尝试。

*  查看当前`pom.xml`具体生效的结果，并且输出到文件: `mvn help:effective-pom -Doutput=EffectivePom.xml`
 *  查看`pom`中生效的`profile`: `mvn help:active-profiles -N`
 *  查看系统所有环境变量: `mvn help:system`