1、查看项目的jdk(Ctrl+Alt+shift+S)
File ->Project Structure->Project Settings ->Project
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2、查看工程的jdk(Ctrl+Alt+shift+S)
File ->Project Structure->Project Settings -> Modules -> (需要修改的工程名称) -> Sources ->
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3、查看idea中Java配置
File ->Setting ->Build,Execution,Deployment -> Compiler -> Java Compiler
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4、清除IDEA缓存 重启IDEA
File->Invalidate Caches/Restart
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5、Maven
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