SSM项目的web.xml的DispatcherServlet爆红原因及解决方案

<dependencies>  
    <!-- SpringMVC -->  
    <dependency>  
        <groupId>org.springframework</groupId>  
        <artifactId>spring-webmvc</artifactId>  
        <version>5.3.1</version>  
    </dependency>  
    <!-- 日志 -->  
    <dependency>  
        <groupId>ch.qos.logback</groupId>  
        <artifactId>logback-classic</artifactId>  
        <version>1.2.3</version>  
    </dependency>  
    <!-- ServletAPI -->  
    <dependency>  
        <groupId>javax.servlet</groupId>  
        <artifactId>javax.servlet-api</artifactId>  
        <version>3.1.0</version>  
        <scope>provided</scope>  
    </dependency>  
    <!-- Spring5和Thymeleaf整合包 -->  
    <dependency>  
        <groupId>org.thymeleaf</groupId>  
        <artifactId>thymeleaf-spring5</artifactId>  
        <version>3.0.12.RELEASE</version>  
    </dependency>  
</dependencies>

<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_4_0.xsd"
         version="4.0">

    <!--
        配置SpringMVC的前端控制器DispatcherServlet
        /:匹配浏览器向服务器发送的所有请求（不包括.jsp）
        /*:匹配浏览器向服务器发送的所有请求（包括.jsp）
        org.springframework.web.servlet.DispatcherServlet
    -->
    <servlet>
        <servlet-name>SpringMVC</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <!--class这里报错就将5.3.1改为5.3.18-->
    </servlet>
    <servlet-mapping>
        <servlet-name>SpringMVC</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
</web-app>

    <dependency>  
        <groupId>org.springframework</groupId>  
        <artifactId>spring-webmvc</artifactId>  
        <version>5.3.18</version>  
    </dependency>