[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 f:\ncyteng\tomcat\logs\access_log.2020-02-19

　　[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 tomcat8:run命令的，结果执行clean的时候就报错了，不能清除log,那是log被某个程序占用了，所以不能清除，刚刚启动的程序没有关闭，terminate.再次启动，ＯＫ了！