元素web-app必须在intellij中声明错误（java，springmvc，maven）

Question

this is my web.xml file which getting element web-app must be declared error

<web-app id="WebApp_ID" version="2.5"
    xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
    http://java.sun.com/xml/ns/j2ee/web-app_2_5.xsd">

    <display-name>SpringMVC 3.2 + Google Chart</display-name>

    <servlet>
        <servlet-name>frontController</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>WEB-INF/applnConfig.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>frontController</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

Answer 1

You are using the deployment descriptor schema (web-app_2_5.xsd) version 2.5 which is in javaee namespace ( http://java.sun.com/xml/ns/javaee ). But You have given J2ee namespace instead ( http://java.sun.com/xml/ns/j2ee ).

Try using the Java EE 7 namespace:

<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">
</web-app>