从SVN导出一个Maven项目，pom.xml首行报错：
Failure to transfer org.codehaus.plexus:plexus-components:pom:1.1.20 from http://maven.oschina.net/content/groups/public/ was cached in the local repository, resolution will not be reattempted until the update interval of CN has elapsed or updates are forced. Original error: Could not transfer artifact org.codehaus.plexus:plexus- components:pom:1.1.20 from/to CN (http://maven.oschina.net/content/groups/public/): java.net.ConnectException: connection timed out to http://maven.oschina.net/ content/groups/public/org/codehaus/plexus/plexus-components/1.1.20/plexus-components-1.1.20.pom
亲测了很多办法，都没有效果，最终找到这个可行的。
<!-- war 打包插件, 设定war包名称不带版本号 --> <plugin> <groupId>org.apache.maven.plugins</groupId> <artifactId>maven-war-plugin</artifactId> <!-- <version>2.5.1</version> --> <version>2.4</version> <configuration> <warName>${project.artifactId}</warName> </configuration> </plugin>
根据该方法，将版本改为2.4，立刻错误消失。但是pom.xml在菜单上还是有红叉，所幸的是该文件已经没有错误了，可以执行。
MAVEN：Failure to transfer org.codehaus.plexus:plexus-io:jar:2.4.1
其他亲测，无效的方案（东方不亮西方亮）：
Maven工程错误 之 Failure to transfer org.codehaus.plexus:plexus-archiver:pom:1.0