maven无法下依赖jar文件的解决方案

问题描述：

　　Plugin org.apache.maven.plugins:maven-clean-plugin:2.5 or one of its dependencies could not be resolved: Failed to read artifact descriptor for org.apache.maven.plugins:maven-clean-plugin:jar:2.5: Could not transfer artifact org.apache.maven.plugins:maven-clean-plugin:pom:2.5 from/to central (https://repo.maven.apache.org/maven2): *INSERT PROXY HERE*: Unknown host *INSERT PROXY HERE*

解决方案：

　　打开apache-maven-3.2.3\conf\settings.xml文件添加如下内容

<mirror>
　　<id>ibiblio.org</id>
　　<name>ibiblio Mirror of http://repo1.maven.org/maven2/</name>
　　<url>http://mirrors.ibiblio.org/pub/mirrors/maven2</url>
　　<mirrorOf>central</mirrorOf>
　　<!-- United States, North Carolina -->
</mirror>
<mirror>
　　<id>jboss-public-repository-group</id>
　　<mirrorOf>central</mirrorOf>
　　<name>JBoss Public Repository Group</name>
　　<url>http://repository.jboss.org/nexus/content/groups/public</url>
</mirror>