IDEA JDK版本切换

1.File->Setting->Build->Complier->Java Compiler->Project bytecode version/Module->Target bytecode version
2.File->Setting->Build->Maven->importing->JDK for importer
3.File->Project Structure->Modules->Language level
4.File->Project Structure->SDKs **
5.File->Project Structure->Project->Project SDK **
6.pom.xml

<java.version> </java.version>