springboot maven項目，為什么build成功，build path也沒錯誤，project-->clean 也沒用，項目上面還是有個紅x呢？
看錯誤信息有提示：
Description Resource Path Location Type
Project configuration is not up-to-date with pom.xml. Select: Maven->Update Project... from the project context menu or use Quick Fix. sendemail line 1 Maven Configuration Problem
Project configuration is not up-to-date with pom.xml. Select: Maven->Update Project... from the project context menu or use Quick Fix. sendemail line 1 Maven Configuration Problem
解決辦法： 右鍵項目
maven-->update project 后就可以了