修改Maven默認鏡像，提高下載速度

在Maven安裝目錄的conf下的settings.xml添加阿里雲Maven鏡像

  <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.
     |
	 <!--Maven自身默認鏡像-->
	 <!--
    <mirror>
      <id>mirrorId</id>
      <mirrorOf>repositoryId</mirrorOf>
      <name>Human Readable Name for this Mirror.</name>
      <url>http://my.repository.com/repo/path</url>
    </mirror>
     -->
	 <!-- Maven配置阿里雲鏡像-->
	 <mirror>
      <id>nexus-aliyun</id>
      <mirrorOf>central</mirrorOf>
      <name>Nexus aliyun</name>
      <url>http://maven.aliyun.com/nexus/content/groups/public</url>
    </mirror>
  </mirrors>

如果想要搜索所需的包，請轉：

https://maven.aliyun.com/mvn/search