认识maven与安装maven
什么是maven
- Maven是Apache的一款开源的项目管理工具
- Maven使用项目对象模型(POM-Project Object Model,项目对象模型)的概念，,可以通过一小段描述信息来管理项目的构建，报告和文档的软件项目管理工具
- 在Maven中每个项目都相当于是一个对象，对象（项目）和对象（项目）之间是有关系的
- 关系包含了：依赖、继承、聚合
maven能做什么
- maven可以非常简单、方便的帮助开发者管理项目
- maven可以简单的实现jar包管理
maven的下载与安装
- 如果已经下载安装了IDEA的话，那么IDEA其实已经集成了maven了，直接就可以使用
- 如果重新下载maven的话需要到maven下载页面进行下载
- 下载完成后直接解压即可
- 然后需要执行
mvn help:system，如果提示命令错误需要自行添加环境变量
- 等待命令执行完成后就会生成
C:\Users\用户名\.m2目录，目录下有repository目录与settings.xml文件夹
- 如果没有
settings.xml文件可以自行从网上下载 一个，下面提供一个阿里镜像的settings.xml文件
<?xml version="1.0" encoding="UTF-8"?>
<!--
Licensed to the Apache Software Foundation (ASF) under one
or more contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
-->
<!--
| 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,
| and is normally provided in ${user.home}/.m2/settings.xml.
|
| NOTE: This location can be overridden with the CLI option:
|
| -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.
|
|-->
<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 http://maven.apache.org/xsd/settings-1.0.0.xsd">
<!-- localRepository
| The path to the local repository maven will use to store artifacts.
|
| Default: ${user.home}/.m2/repository
<localRepository>/path/to/local/repo</localRepository>
-->
<localRepository>C:\Users\Administrator\.m2\repository</localRepository>
<!-- 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
<interactiveMode>true</interactiveMode>
-->
<!-- 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
<offline>false</offline>
-->
<!-- 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.
|-->
<pluginGroups>
<!-- pluginGroup
| Specifies a further group identifier to use for plugin lookup.
<pluginGroup>com.your.plugins</pluginGroup>
-->
<pluginGroup>org.mortbay.jetty</pluginGroup>
</pluginGroups>
<!-- 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
| 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
| 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>
-->
<server>
<id>releases</id>
<username>ali</username>
<password>ali</password>
</server>
<server>
<id>Snapshots</id>
<username>ali</username>
<password>ali</password>
</server>
</servers>
<!-- 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.
|-->
<mirrors>
<!-- mirror
| Specifies a repository mirror site to use instead of a given repository. The repository that
| this mirror serves has an ID that matches the mirrorOf element of this mirror. IDs are used
| for inheritance and direct lookup purposes, and must be unique across the set of mirrors.
|
<mirror>
<id>mirrorId</id>
<mirrorOf>repositoryId</mirrorOf>
<name>Human Readable Name for this Mirror.</name>
<url>http://my.repository.com/repo/path</url>
</mirror>
-->
<!-- <mirror>
<id>nexus</id>
<mirrorOf>*</mirrorOf>
<url>http://maven.aliyun.com/nexus/content/groups/public/</url>
</mirror>
<mirror>
<id>nexus-public-snapshots</id>
<mirrorOf>public-snapshots</mirrorOf>
<url>http://maven.aliyun.com/nexus/content/repositories/snapshots/</url>
</mirror> -->
<mirror>
<!-- 指定镜像ID（可自己改名） -->
<id>nexus-aliyun</id>
<!-- 匹配中央仓库（阿里云的仓库名称，不可以自己起名，必须这么写）-->
<mirrorOf>central</mirrorOf>
<!-- 指定镜像名称（可自己改名） -->
<name>Nexus aliyun</name>
<!-- 指定镜像路径（镜像地址） -->
<url>http://maven.aliyun.com/nexus/content/groups/public</url>
</mirror>
</mirrors>
<!-- profiles
| This is a list of profiles which can be activated in a variety of ways, and which can modify
| the build process. Profiles provided in the settings.xml are intended to provide local machine-
| specific paths and repository locations which allow the build to work in the local environment.
|
| For example, if you have an integration testing plugin - like cactus - that needs to know where
| your Tomcat instance is installed, you can provide a variable here such that the variable is
| dereferenced during the build process to configure the cactus plugin.
|
| As noted above, profiles can be activated in a variety of ways. One way - the activeProfiles
| section of this document (settings.xml) - will be discussed later. Another way essentially
| relies on the detection of a system property, either matching a particular value for the property,
| or merely testing its existence. Profiles can also be activated by JDK version prefix, where a
| value of '1.4' might activate a profile when the build is executed on a JDK version of '1.4.2_07'.
| Finally, the list of active profiles can be specified directly from the command line.
|
| NOTE: For profiles defined in the settings.xml, you are restricted to specifying only artifact
| repositories, plugin repositories, and free-form properties to be used as configuration
| variables for plugins in the POM.
|
|-->
<profiles>
<!-- <profile>
<id>development</id>
<repositories>
<repository>
<id>central</id>
<url>http://central</url>
<releases><enabled>true</enabled><updatePolicy>always</updatePolicy></releases>
<snapshots><enabled>true</enabled><updatePolicy>always</updatePolicy></snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>central</id>
<url>http://central</url>
<releases><enabled>true</enabled><updatePolicy>always</updatePolicy></releases>
<snapshots><enabled>true</enabled><updatePolicy>always</updatePolicy></snapshots>
</pluginRepository>
</pluginRepositories>
</profile>
<profile>
<id>public-snapshots</id>
<repositories>
<repository>
<id>public-snapshots</id>
<url>http://public-snapshots</url>
<releases><enabled>false</enabled></releases>
<snapshots><enabled>true</enabled><updatePolicy>always</updatePolicy></snapshots>
</repository>
</repositories>
<pluginRepositories>
<pluginRepository>
<id>public-snapshots</id>
<url>http://public-snapshots</url>
<releases><enabled>false</enabled></releases>
<snapshots><enabled>true</enabled><updatePolicy>always</updatePolicy></snapshots>
</pluginRepository>
</pluginRepositories>
</profile> -->
<profile>
<!-- settings.xml中的id不能随便起的 -->
<!-- 告诉maven我们用jdk1.8 -->
<id>jdk-1.8</id>
<!-- 开启JDK的使用 -->
<activation>
<activeByDefault>true</activeByDefault>
<jdk>1.8</jdk>
</activation>
<properties>
<!-- 配置编译器信息 -->
<maven.compiler.source>1.8</maven.compiler.source>
<maven.compiler.target>1.8</maven.compiler.target>
<maven.compiler.compilerVersion>1.8</maven.compiler.compilerVersion>
</properties>
</profile>
</profiles>
<activeProfiles>
<activeProfile>development</activeProfile>
<activeProfile>public-snapshots</activeProfile>
</activeProfiles>
</settings>
