1.安装java11 

1.1 安装参考

​​​​​​LINUX安装JDK_liunx上安装ocean-CSDN博客

1.2 检查

java -version

2.Maven 项目pom文件修改

    <properties><project.build.sourceEncoding>UTF-8</project.build.sourceEncoding><project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding><java.version>11</java.version><maven.compiler.source>11</maven.compiler.source><maven.compiler.target>11</maven.compiler.target></properties>

3.Idea配置修改

4.低版本运行高版本编译代码报错

has been compiled by a more recent version of the Java Runtime