转载：https://blog.csdn.net/u012562943/article/details/61916067
第一步：看settings.xml的内容解释
<!--
| #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
| This is the configuration file for Maven. It can be specified at two levels:
| 1. User Level. This settings.xml file provides configuration for a single user,
| |#其中的CLI选项指的是mvn操作命令的相关参数比如：mvn -v
| and is normally provided in ${user.home}/.m2/settings.xml.
| NOTE: This location can be overridden with the CLI option:
| #全局级别，即面向所有用户同一配置
| | -s /path/to/user/settings.xml
| 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
| ${maven.home}/conf/settings.xml. | | NOTE: This location can be overridden with the CLI option:
| | -gs /path/to/global/settings.xml
| | The sections in this sample file are intended to give you a running start at
| getting the most out of your Maven installation. Where appropriate, the default
| values (values used when the setting is not specified) are provided.
-->
明白settings.xml具有两个级别：用户级别和全局级别
settings.xml配置文件属于maven的相关配置，配置的是其他工程项目pom.xml中的全局配置
第二步：了解settings.xml标准参数结构
localRepository 本地仓库配置路径 interactiveMode 是否交互式输入提醒。默认true offline 是否每次编译部署时候需要联网，默认false pluginGroups 插件组合，供编译时选用 proxies 代理配置，连接本地无法远程的网络 servers 服务配置，上传构件/连接仓库所用 mirrors 替代有网络问题的repository的访问站点 profiles 应用于不同环境的配置 activeProfiles 激活指定的配置，与profile搭配使用
第三步：详解以上的参数含义
localRepository 保存远程下载的构建的本地位置，采用绝对路径，默认存放在${user.home}/.m2/repository
<!--
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，建议设置为true
<!--
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，提高build效率、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.
-->
示例：mvn jetty run替代org.morbay.jetty:jetty-maven-plugin:run
<pluginGroups>
<pluginGroup> org.mortbay.jetty </pluginGroup>
</pluginGroups>
proxies 代理配置，默认第一个proxy配置起效
<!--
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>
servers配置，上传构件需要验证的server配置，通过id来应用，与mirror/repository标签的id相一致
<!--
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>
-->
<!-- 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 构建镜像，替代有网络问题的repository的访问站点，即当下载的maven构建有问题时可通过此配置替换原有的下载地址
<!--
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官网的中央仓库
-->
示例：
<mirror>
<id>mirrorId</id>
#指定替代的唯一仓库id或者*代表所有都替代，支持多仓库id，以逗号分隔
<mirrorOf>repositoryId/*</mirrorOf>
<name>Human Readable Name for this Mirror.</name>
#镜像url
<url>http://my.repository.com/repo/path</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
| This profile example uses the JDK version to trigger activation, and provides a JDK-specific repo.
<profile>
#唯一id
<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>
<repositories>
<repository>
#与server的id一致
<id>jdk14</id>
<name>Repository for JDK 1.4 builds</name>
#发布版本
<releases>
#不允许在发布版本中寻找构件
<enabled>false</enabled>
<updatePolicy>always</updatePolicy>
<checksumPolicy>warn</checksumPolicy>
</releases>
#快照版本
<snapshots>
#允许在快照版本中寻找构件
<enabled>true</enabled>
<updatePolicy>never</updatePolicy>
<checksumPolicy>fail</checksumPolicy>
</snapshots>
<url>http://www.myhost.com/maven/jdk14</url>
<layout>default</layout>
<snapshotPolicy>always</snapshotPolicy>
</repository>
</repositories>
</profile>
-->
activeProfiles 激活相应的profile配置，可激活多个配置
activeProfiles //List of profiles that are active for all builds.
<activeProfiles>
<activeProfile>alwaysActiveProfile</activeProfile>
<activeProfile>anotherAlwaysActiveProfile</activeProfile>
</activeProfiles>
distributionManagement(新增) 上传构件
<distributionManagement>
<repository>
#对应发布版本的server.id
<id>release_server</id>
<url></url>
</repository>
<snapshotRepository>
#对应快照版本的server.id
<id>snapshot_server</id>
<url></url>
</snapshotRepository>
repositories(新增) 统一的下载仓库
<repositories>
<repository>
#对应server.id
<id>snapshot</id>
#下载构件的仓库url
<url></url>
<releases>
#不支持发布版本的查询
<enabled>false</enabled>
</releases>
<snapshots>
#支持快照版本的查询
<enabled>true</enabled>
</snapshots>
</repository>
</repositories>
总结
mirror是下载构件的配置，其中的id属性在其下载构件需要server验证时候对应的server.id
mirror的优先级高于repository
distributionManagement是用在上传构件到远程服务器的配置，其中的repository配置中的id也对应server.id，毕竟上传构件需要server验证