web.xml配置

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  <servlet>
      <servlet-name>ssm3</servlet-name>
      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
      <init-param>
          <param-name>contextConfigLocation</param-name>
          <param-value>classpath*:servlet-context.xml</param-value>
      </init-param>
      <load-on-startup>1</load-on-startup>
  </servlet>
  
  <servlet-mapping>
      <servlet-name>ssm3</servlet-name>
      <url-pattern>/</url-pattern>
  </servlet-mapping>
  
  <context-param>
      <param-name>contextConfigLocation</param-name>
      <param-value>classpath*:service-context.xml</param-value>
  </context-param>
</web-app>

这样写会报错：

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*)".

要按顺序来写，调整context-param和servlet的顺序就可以了：

<web-app>
    <display-name>Archetype Created Web Application</display-name>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>classpath*:service-context.xml</param-value>
    </context-param>
    
    <servlet>
        <servlet-name>ssm3</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>classpath*:servlet-context.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>ssm3</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>