1.打开项目所在目录下的.settings文件夹
打开org.eclipse.wst.common.project.facet.core.xml
把<installed facet="java" version="1.5"/>改成<installed facet="java" version="1.8"/>，把 <installed facet="jst.web" version="2.3"/>改成 <installed facet="jst.web" version="3.0"/>
<?xml version="1.0" encoding="UTF-8"?><faceted-project> ?<fixed facet="wst.jsdt.web"/> ?<installed facet="java" version="1.8"/> ?<installed facet="jst.web" version="3.0"/> ?<installed facet="wst.jsdt.web" version="1.0"/></faceted-project>
2.在pom.xml中增加
<!-- define the project compile level --> ??????????<plugin> ???????????<groupId>org.apache.maven.plugins</groupId> ???????????<artifactId>maven-compiler-plugin</artifactId> ?????????????????????<configuration> ???????????????<source>1.8</source> ???????????????<target>1.8</target> ???????????</configuration> ???????</plugin>
解决maven项目Cannot change version of project facet Dynamic web module to 3.0/3.1
原文地址：https://www.cnblogs.com/achengmu/p/9101669.html