The content of element type "web-app" must match "(icon?,display- name?,description?,distributable?,context-param,filter,filter-mapping,listener,servlet,servlet- mapping,session-config?

web.xml头部配置：

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE web-app PUBLIC "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd">
<web-app>

原因：文档内容标签顺序不符合web-app_2_3.dtd规范