新建maven web项目时，将dynamic web module由2.3改成3.0时，提示错误：
java
cannot change version of project facet dynamic web module to 3.0。web
解决办法是：app
1）打开该项目在本地的地址，如项目名称是test，找到该目录下的 .settings/org.eclipse.wst.common.project.facet.core.xml文件（好比路径是：E:\eclipse\test\.settings\org.eclipse.wst.common.project.facet.core.xml）eclipse
修改web version为3.0：maven
<?xml version="1.0" encoding="UTF-8"?> <faceted-project> <runtime name="Apache Tomcat v7.0"/> <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）修改该项目（test）的web.xml头信息，以下：spa
<?xml version="1.0" encoding= "UTF-8"?> <web-app xmlns:xsi= "http://www.w3.org/2001/XMLSchema-instance" xmlns= "http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id= "WebApp_ID" version = "3.0"> < display-name>Archetype Created Web Application </display-name > </web-app>
至此，dynamic web module已自动改成3.0.code