完整报错信息：
Maven项目报错：Failed to execute goal org.apache.maven.plugins:maven-clean-plugin:2.5:clean (default-clea
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-clean-plugin:2.5:clean (default-clean) on project study-search: Failed to clean project: Failed to delete D:\Pxxtarget\tomcat\logs\access_log.2017-3-24
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
本来是执行clean tomcat7:run命令的，结果执行clean的时候就报错了，不能清除log,那就是log被某个程序占用了，所以不能清除，因此需要从任务管理器里把javaw. exe进程关闭即可。然后重新运行