需求描述

複雜的maven專案，通常包含多個子模組專案，如果手工逐個去修改每個pom.xml，會非常的耗時耗力，而且容易出錯和遺漏。

解決方案

藉助maven的versions外掛，可以比較容易的解決這個問題。方法如下：

mvn versions:set -DnewVersion=0.29-SNAPSHOT

versions外掛還提供了其它靈活的功能，可以通過"mvn versions:help"來檢視幫助資訊，根據選項的描述來實驗一下實際效果。

bj-m-211510a:target jinguang1$ mvn versions:help
[INFO] Scanning for projects...
[INFO]
[INFO] ------------------< org.apache.maven:standalone-pom >-------------------
[INFO] Building Maven Stub Project (No POM) 1
[INFO] --------------------------------[ pom ]---------------------------------
[INFO]
[INFO] --- versions-maven-plugin:2.5:help (default-cli) @ standalone-pom ---
[INFO] Versions Maven Plugin 2.5
  Versions Plugin for Maven. The Versions Plugin updates the versions of
  components in the POM.

This plugin has 31 goals:

versions:commit
  Removes the initial backup of the pom, thereby accepting the changes.

versions:compare-dependencies
  Compare dependency versions of the current project to dependencies or
  dependency management of a remote repository project. Can optionally update
  locally the project instead of reporting the comparison

versions:dependency-updates-report
  Generates a report of available updates for the dependencies of a project.

versions:display-dependency-updates
  Displays all dependencies that have newer versions available. It will also
  display dependencies which are used by a plugin or defined in the plugin
  within a pluginManagement.

versions:display-parent-updates
  Displays any updates of the project's parent project

versions:display-plugin-updates
  Displays all plugins that have newer versions available.

versions:display-property-updates
  Displays properties that are linked to artifact versions and have updates
  available.

versions:force-releases
  Replaces any -SNAPSHOT versions with a release version, older if necessary (if
  there has been a release).

versions:help
  Display help information on versions-maven-plugin.
  Call mvn versions:help -Ddetail=true -Dgoal=<goal-name> to display parameter
  details.

versions:lock-snapshots
  Attempts to resolve unlocked snapshot dependency versions to the locked
  timestamp versions used in the build. For example, an unlocked snapshot
  version like '1.0-SNAPSHOT' could be resolved to '1.0-20090128.202731-1'. If a
  timestamped snapshot is not available, then the version will remained
  unchanged. This would be the case if the dependency is only available in the
  local repository and not in a remote snapshot repository.

versions:plugin-updates-report
  Generates a report of available updates for the plugins of a project.

versions:property-updates-report
  Generates a report of available updates for properties of a project which are
  linked to the dependencies and/or plugins of a project.

versions:resolve-ranges
  Attempts to resolve dependency version ranges to the specific version being
  used in the build. For example a version range of '[1.0, 1.2)' would be
  resolved to the specific version currently in use '1.1'.

versions:revert
  Restores the pom from the initial backup.

versions:set
  Sets the current project's version and based on that change propagates that
  change onto any child modules as necessary.

versions:set-property
  Set a property to a given version without any sanity checks. Please be careful
  this can lead to changes which might not build anymore. The sanity checks are
  done by other goals like update-properties or update-property etc. they are
  not done here. So use this goal with care.

versions:set-scm-tag
  Updates the current project's SCM tag.

versions:unlock-snapshots
  Attempts to resolve unlocked snapshot dependency versions to the locked
  timestamp versions used in the build. For example, an unlocked snapshot
  version like '1.0-SNAPSHOT' could be resolved to '1.0-20090128.202731-1'. If a
  timestamped snapshot is not available, then the version will remained
  unchanged. This would be the case if the dependency is only available in the
  local repository and not in a remote snapshot repository.

versions:update-child-modules
  Scans the current projects child modules, updating the versions of any which
  use the current project to the version of the current project.

versions:update-parent
  Sets the parent version to the latest parent version.

versions:update-properties
  Sets properties to the latest versions of specific artifacts.

versions:update-property
  Sets a property to the latest version in a given range of associated
  artifacts.

versions:use-dep-version

versions:use-latest-releases
  Replaces any release versions with the latest release version.

versions:use-latest-snapshots
  Replaces any release versions with the latest snapshot version (if it has been
  deployed).

versions:use-latest-versions
  Replaces any version with the latest version.

versions:use-next-releases
  Replaces any release versions with the next release version (if it has been
  released).

versions:use-next-snapshots
  Replaces any release versions with the next snapshot version (if it has been
  deployed).

versions:use-next-versions
  Replaces any version with the latest version.

versions:use-reactor
  Replaces any versions with the corresponding version from the reactor.

versions:use-releases
  Replaces any -SNAPSHOT versions with the corresponding release version (if it
  has been released).