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

笔者最近学习一些spring mvc，在复制别人代码的时候报这个错。报错来源web.xml，原因是不符合xsd对xml的约束

源文件

<?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">

    <servlet>
        <!--名称 -->
        <servlet-name>springmvc</servlet-name>
        <!-- Servlet类 -->
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!-- 启动顺序，数字越小，启动越早 -->
        <load-on-startup>1</load-on-startup>
        <init-param>
            <!--SpringMVC配置参数文件的位置 -->
            <param-name>contextConfigLocation</param-name>
            <!--默认名称为ServletName-servlet.xml -->
            <param-value>classpath*:springmvc-servlet.xml</param-value>
        </init-param>
    </servlet>

    <!--所有请求都会被springmvc拦截 -->
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>

解决方法:

调整<load-on-startup>节点的顺序，放到</servlet>之前，修改后的web.xml如下

<?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">

    <servlet>
        <!--名称 -->
        <servlet-name>springmvc</servlet-name>
        <!-- Servlet类 -->
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <!--SpringMVC配置参数文件的位置 -->
            <param-name>contextConfigLocation</param-name>
            <!--默认名称为ServletName-servlet.xml -->
            <param-value>classpath*:springmvc-servlet.xml</param-value>
        </init-param>
        <!-- 启动顺序，数字越小，启动越早 -->
        <load-on-startup>1</load-on-startup> 
    </servlet>

    <!--所有请求都会被springmvc拦截 -->
    <servlet-mapping>
        <servlet-name>springmvc</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>

</web-app>