在maven clean的时候一直报这个错误：
Cannot access nexus (http://110.110.110.42:8082/repository/maven-public/) in offline mode and the artifact org.springframework.boot:spring-boot-starter-parent:pom:2.0.1.RELEASE has not been downloaded from it before. and ‘parent.relativePath’ points at no local POM @ line 15, column 13
查找资料发现是,maven默认配置 work offline, 去掉勾选：