<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
version="3.1" metadata-complete="true">
?<display-name>Archetype Created Web Application</display-name>
</web-app>
<build> ???<finalName>YMX</finalName> ???<plugins> ???????<plugin> ????????????<groupId>org.apache.maven.plugins</groupId> ????????????<artifactId>maven-compiler-plugin</artifactId> ????????????<version>3.1</version> ????????????<configuration> ????????????????<source>1.8</source> ?????????????????????<target>1.8</target> ??????????????????</configuration> ??????</plugin> ???</plugins> ?</build>
MAVEN --> update project
新建maven项目更改 web版本
原文地址：https://www.cnblogs.com/yuanbaodong/p/8267246.html