cvc-complex-type.2.4.a: Invalid content was found starting with element 'async-supported'

<servlet>
<servlet-name>springMVC</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:spring-mvc.xml</param-value>
</init-param>
<async-supported>true</async-supported>
<load-on-startup>1</load-on-startup>
</servlet>

解决办法：将web.xml的版本换成是3.0的，因为servlet3.0以后是不需要配置web了，这里用到的3.0版本的servlet如果需要web的时候一定要换成3.0的

<?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">