The content of element type "web-app" must match "( ***

WEB项目报错

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?,mime-mapping,welcome-file-list?,error-page,taglib,resource-env-ref,resource- ref,security-constraint,login-config?,security-role,env-entry,ejb-ref,ejb-local-ref)".

原因

web.xml头文件比较旧。规定了代码的书写顺序所以报错。

解决方案

按照规定的顺序写代码。或者替换头文件为其他版本。

web.xml v2.5

 <?xml version="1.0" encoding="UTF-8"?>
 <web-app xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee  http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"     version="2.5">

</web-app>

web.xml v3.0

 <?xml version="1.0" encoding="UTF-8"?>
<web-app
 version="3.0"
 xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  xsi:schemaLocation="http://java.sun.com/xml/ns/javaee   http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
</web-app>