Maven settings.xml配置解读

时间:2021-10-23 14:41:20

请确保自己的maven环境安装成功,具体安装流程详见Maven安装

在安装完maven环境后,最重要的就是去配置settings.xml文件,其作为统一的依赖配置管理入口,了解其相关配置有助于我们对maven的理解

settings.xml主配置文件

笔者此处优先查看其注释内容,信息如下

<!--
| This is the configuration file for Maven. It can be specified at two levels:
| #用户级别,面向单个用户配置,即每个用户都可以自定义settings.xml供己方使用
| 1. User Level. This settings.xml file provides configuration for a single user,
| and is normally provided in ${user.home}/.m2/settings.xml.
|
| #其中的CLI选项指的是mvn操作命令的相关参数比如:mvn -v
| NOTE: This location can be overridden with the CLI option:
|
| -s /path/to/user/settings.xml
| #全局级别,即面向所有用户同一配置
| 2. Global Level. This settings.xml file provides configuration for all Maven
| users on a machine (assuming they're all using the same Maven
| installation). It's normally provided in
| ${maven.home}/conf/settings.xml.
|
| NOTE: This location can be overridden with the CLI option:
|
| -gs /path/to/global/settings.xml
|
| The sections in this sample file are intended to give you a running start at
| getting the most out of your Maven installation. Where appropriate, the default
| values (values used when the setting is not specified) are provided.
|
|-->

由上可得

  1. settings.xml具有两个级别:用户级别和全局级别,一般我们只需要去配置用户级别即可
  2. settings.xml配置的是所有POM工程项目的全局配置

主要参数配置

笔者罗列出主要的参数配置

	## 此处的构件我们简单的理解为依赖,针对JAVA就是JAR包
localRepository 本地仓库配置路径
interactiveMode 是否交互式输入提醒,默认true
offline 是否每次编译部署时候需要联网,默认false
pluginGroups 插件组合,供编译时选用
proxies 代理配置,连接本地无法远程的网络
servers 服务配置,上传构件/连接仓库所用
mirrors 替代有网络问题的repository的访问站点
profiles 应用于不同环境的配置
activeProfiles 激活指定的配置,与profile搭配使用

对上述的参数分别作下简单的描述,更多的解释可详见官网Maven-Settings Reference

localRepository

本地仓库路径,主要用于存放从远程仓库下载的构件依赖。采用绝对路径,默认存放在${user.home}/.m2/repository路径下

<!-- localRepository
| The path to the local repository maven will use to store artifacts.
|
| Default: ${user.home}/.m2/repository-->

interactiveMode

交互式节点配置,默认为true。设置为false则会在mvn执行中使用默认的参数设置交互性问题

<!-- interactiveMode
| This will determine whether maven prompts you when it needs input. If set to false,
| maven will use a sensible default value, perhaps based on some other setting, for
| the parameter in question.
|
| Default: true-->

offline

是否每次的编译部署都需要联网,默认为false。如果构件不需要更新下载则可设置为true,以提高build效率和成功率。

<!-- offline
| Determines whether maven should attempt to connect to the network when executing a build.
| This will have an effect on artifact downloads, artifact deployment, and others.
|
| Default: false-->

pluginGroups

插件组,默认包含maven插件、mojo插件,用于插件在使用时没有指定groupId时,这个列表就会被搜索。

!-- pluginGroups
| This is a list of additional group identifiers that will be searched when resolving plugins by their prefix, i.e.
| when invoking a command line like "mvn prefix:goal". Maven will automatically add the group identifiers
| "org.apache.maven.plugins" and "org.codehaus.mojo" if these are not already contained in the list.
|-->

举个例子:

<pluginGroups>
<pluginGroup>
org.mortbay.jetty
</pluginGroup>
</pluginGroups>

上述配置后,可通过mvn jetty run替代长命令org.morbay.jetty:jetty-maven-plugin:run

proxies

网络代理配置

<!-- proxies
| This is a list of proxies which can be used on this machine to connect to the network.
| Unless otherwise specified (by system property or command-line switch), the first proxy
| specification in this list marked as active will be used.
|-->
<proxies>
<!-- proxy 新增一个代理配置示例
| Specification for one proxy, to be used in connecting to the network.
|
<proxy>
<id>optional</id>
<active>true</active>
<protocol>http</protocol>
<username>proxyuser</username>
<password>proxypass</password>
<host>proxy.host.net</host>
<port>80</port>
<nonProxyHosts>local.net|some.host.com</nonProxyHosts>
</proxy>
-->
</proxies>

默认以第一个配置的代理节点作为网络的通信(正向代理)。主要用于解决构件下载不到的问题

servers

上传或者下载构件时所需要验证的服务器配置。通过id来区分,主要与mirror/repository配置搭配使用

有两种方式的校验,此配置有助于用户可以搭建自己的maven私库。


密码方式校验(推荐)

 <!-- servers
| This is a list of authentication profiles, keyed by the server-id used within the system.
| Authentication profiles can be used whenever maven must make a connection to a remote server.
|-->
<servers>
<!-- server
| Specifies the authentication information to use when connecting to a particular server, identified by
| a unique name within the system (referred to by the 'id' attribute below).
|
| NOTE: You should either specify username/password OR privateKey/passphrase, since these pairings are
| used together.
|
<server>
<id>deploymentRepo</id>
<username>repouser</username>
<password>repopwd</password>
</server>
-->

privateKey方式校验,更为安全的认证方式

  <servers>
<!-- Another sample, using keys to authenticate.
<server>
<id>siteServer</id>
<privateKey>/path/to/private/key</privateKey>
<passphrase>optional; leave empty if not used.</passphrase>
</server>
-->
</servers>

mirrors

构件镜像,替代有网络问题的仓库的访问站点。即当maven构件出现下载问题时便通过此配置替换原有的下载地址去下载

<!-- mirrors
| This is a list of mirrors to be used in downloading artifacts from remote repositories.
|
| It works like this: a POM may declare a repository to use in resolving certain artifacts.
| However, this repository may have problems with heavy traffic at times, so people have mirrored
| it to several places.
|
| That repository definition will have a unique id, so we can create a mirror reference for that
| repository, to be used as an alternate download site. The mirror site will be the preferred
| server for that repository. //central代表maven官网的*仓库
|-->

举个例子

	<mirror>
<!--与server参数配置的id属性一致,登录校验-->
<id>${server_id}</id>
<!--拦截指定的仓库,支持多仓库id,以逗号分隔(*代表拦截所有的仓库,central代表拦截maven官方*仓库)-->
<mirrorOf>${repository_id}/*</mirrorOf>
<name>Human Readable Name for this Mirror.</name>
<!--服务器地址-->
<url>http://my.repository.com/repo/path</url>#镜像url
</mirror>

profiles

多条件集合配置,用于不同条件下可应用不同的配置,其中也可配置自定义的repository/pluginRepository。灵活性很高

	| This profile example uses the JDK version to trigger activation, and provides a JDK-specific repo.
<profile>
<id>jdk-1.4</id>
<!--在此配置的任何一个节点条件满足则触发此配置-->
<activation>
<jdk>1.4</jdk>
</activation>
<!--仓库配置-->
<repositories>
<repository>
<id>jdk14</id>#唯一ID,可与server搭配使用
<name>Repository for JDK 1.4 builds</name>
<releases>#发布版本
<enabled>false</enabled> #不允许在发布版本中寻找构件
<updatePolicy>always</updatePolicy> #检查构件更新的策略
<checksumPolicy>warn</checksumPolicy>
</releases>
<snapshots>#快照版本
<enabled>true</enabled>#允许在快照版本中寻找构件
<updatePolicy>never</updatePolicy>
<checksumPolicy>fail</checksumPolicy>
</snapshots>
<url>http://www.myhost.com/maven/jdk14</url>
<layout>default</layout>
<snapshotPolicy>always</snapshotPolicy>
</repository>
</repositories>
</profile>

像上述的例子,用户只需要jdk版本大于1.4,上述的profile便会生效。

activeProfiles

profile参数搭配使用,用于激活相应的profile配置,可激活多个配置

  <activeProfiles>
<activeProfile>${profile_id1}</activeProfile>
<activeProfile>${profile_id2}</activeProfile>
</activeProfiles>

总结

  1. server节点是仓库服务器的配置,有密码校验方式和私钥校验方式。其下的id配置应用于mirror/repository节点用于登录校验

  2. mirror节点配置会根据其内部的mirrorOf配置拦截指定的repository。

    如果指定为*则会拦截所有的仓库;

    指定为central则会拦截https://repo.maven.apache.org/maven2/

  3. profile节点则可由用户灵活配置,可用于不同条件下的环境配置