报错场景：

IDEA运行Java项目报错，点击运行之后，IDEA在编译代码的时候就出现报错：

报错类型一：java: 错误: 不支持发行版本 21报错类型二：java: 错误: 无效的源发行版：21

详细报错如下：

Executing pre-compile tasks...
Running 'before' tasks
Checking sources
Copying resources... [spring6-ioc-annotation]
Checking dependencies… [spring6-ioc-annotation]
Dependency analysis found 0 affected files
Updating dependency information… [spring6-ioc-annotation]
Searching for compilable files... [spring6-ioc-annotation]
Parsing java… [spring6-ioc-annotation]
java: 错误: 不支持发行版本 21
Dependency analysis found 0 affected files
Errors occurred while compiling module 'spring6-ioc-annotation'
javac 17 was used to compile java sources
Finished, saving caches…
Module 'spring6-ioc-annotation' was fully rebuilt due to project configuration/dependencies changes
Compilation failed: errors: 1; warnings: 0
Executing post-compile tasks...
Compilation failed: errors: 1; warnings: 0
Synchronizing output directories...
2024/3/5 10:28 - Build completed with 1 error and 0 warnings in 4 sec, 114 ms

截图如下：

报错原因：

Javac编译器的版本与JDK版本不对应

解决方法：

参考以下文章：

IDEA切换JDK版本详细步骤

保持文章里面4大点的版本一直即可：

• ①File——>Project Structure——>Project；
• ②File——>Project Structure——>Modules；
• ③File——>Project Structure——>SDKs；
• ④File——>Settings——>Build, Execution, Deployment——>Compiler——>Java Compiler。

例如，我这里是第四点的版本不一致：