问题：
Could not calculate build plan: Failure to transfer org.apache.maven.plugins:maven-surefire-plugin:pom:2.7.1 from http://repo1.maven.org/maven2 was cached in the local repository, resolution will not be reattempted until the update interval of central has elapsed or updates are forced. Original error: Could not transfer artifact org.apache.maven.plugins:maven-surefire-plugin:pom:2.7.1 from/to central (http://repo1.maven.org/maven2): Access denied to http://repo1.maven.org/maven2/org/apache/maven/plugins/maven-surefire-plugin/2.7.1/maven-surefire-plugin-2.7.1.pom. Error code 407, Proxy Authentication Required ( The ISA Server requires authorization to fulfill the request. Access to the Web Proxy service is denied. )log4j-test01UnknownMaven Problem
解决方法：
1.找到maven库目录，进入：~\.m2\repository\org\apache\maven\plugins\maven-surefire-plugin\2.7.1
2.若2.7.1目录下只有，"maven-surefire-plugin-2.7.1.pom.lastUpdated" 则需要到http://repo1.maven.org/maven2/org/apache/maven/plugins/maven-surefire-plugin/2.7.1/，把里面的文件下载下来放到2.7.1
3.删除2.7.1下的maven-surefire-plugin-2.7.1.pom.lastUpdated文件。
4.项目右键-->maven-->Update Dependencies
from:http://blog.csdn.net/lsls22/article/details/6934370