The plugin 'org.apache.maven.plugins:maven-jetty-plugin' does not exist or no va

http://blog.csdn.net/helen_phding/article/details/6224139

conf/setting.xml里面：

  <!-- 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>org.mortbay.jetty</pluginGroup>
    <!-- pluginGroup
     | Specifies a further group identifier to use for plugin lookup.
    <pluginGroup>com.your.plugins</pluginGroup>
    -->
  </pluginGroups>