ClassCastException：org.springframework.web.servlet.DispatcherServlet 不能转换为 javax.servlet.Servlet

Question

我使用 maven-eclipse 创建了一个新的 Spring MVC 项目并抛出以下错误：

（我尝试了一些在我的情况下不起作用的 stackoverflow 解决方案。我找不到 pom.xml 的一些问题。我为 servlet-api 添加了 provided 范围并尝试了它也不起作用。）

SEVERE: Servlet /Remindem threw load() exception
java.lang.ClassCastException: 
org.springframework.web.servlet.DispatcherServlet cannot be cast to javax.servlet.Servlet

我的 pom.xml

<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>servlet-api</artifactId>
  <version>2.5</version>
  <scope>provided</scope>
</dependency>
<dependency>
  <groupId>javax.servlet.jsp</groupId>
  <artifactId>jsp-api</artifactId>
  <version>2.1</version>
  <scope>provided</scope>
</dependency>
<dependency>
  <groupId>javax.servlet</groupId>
  <artifactId>jstl</artifactId>
  <version>1.2</version>
</dependency>

我的 web.xml

上下文配置位置 /WEB-INF/classes/config/spring/*-context.xml

<!-- Creates the Spring Container shared by all Servlets and Filters -->
<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<!-- Processes application requests -->
<servlet>
    <servlet-name>appServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            /WEB-INF/classes/config/spring/servlet_context.xml
        </param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>appServlet</servlet-name>
    <url-pattern>*.do</url-pattern>
</servlet-mapping>

Answer 1

尝试如下更改配置。

<init-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>
        /WEB-INF/classes/config/spring/servlet_context.xml
    </param-value>
</init-param>

<listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<!-- Processes application requests -->
<servlet>
    <servlet-name>appServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>appServlet</servlet-name>
    <url-pattern>*.do</url-pattern>
</servlet-mapping>

DispatcherServlet 默认使用不需要 init-param

XXXX-servlet.xml，其中 XXXX 是 servlet 的名称

确保这些依赖项在您的 pom.xml 中

 <!-- Spring dependencies section -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${spring.version}</version>
    </dependency>

Answer 2

从 pom.xml 中删除 servlet-api，因为它将在服务器中可用。

这是我的 pom.xml： http://maven.apache.org/maven-v4_0_0.xsd"> 4.0.0 com.mkyong CounterWebApp 战争 1.0-快照 CounterWebApp Maven Webapp http://maven.apache.org 1.8 3.0.5.RELEASE --> 4.1.1.发布 1.2 4.11 1.0.13 1.7.5

<dependencies>
    <!-- Unit Test -->
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>${junit.version}</version>
    </dependency>
    <!-- Spring Core -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>${spring.version}</version>
        <exclusions>
            <exclusion>
                <groupId>commons-logging</groupId>
                <artifactId>commons-logging</artifactId>
            </exclusion>
        </exclusions>
    </dependency>
    <!--Binding for commons logging over slf4j-->
    <dependency>
        <groupId>org.slf4j</groupId>
        <artifactId>jcl-over-slf4j</artifactId>
        <version>${jcl-over-slf4j.version}</version>
        <scope>runtime</scope>
    </dependency>       
    <dependency>
        <groupId>ch.qos.logback</groupId>
        <artifactId>logback-classic</artifactId>
        <version>${logback.version}</version>
    </dependency>       
     <!-- Spring dependencies section -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-webmvc</artifactId>
        <version>${spring.version}</version>
    </dependency>
    <!-- jstl -->
    <dependency>
        <groupId>jstl</groupId>
        <artifactId>jstl</artifactId>
        <version>${jstl.version}</version>
    </dependency>
</dependencies>

<build>
    <finalName>CounterWebApp</finalName>
    <plugins>
        <!-- Eclipse project -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-eclipse-plugin</artifactId>
            <version>2.9</version>
            <configuration>
                <!-- Always download and attach dependencies source code -->
                <downloadSources>true</downloadSources>
                <downloadJavadocs>false</downloadJavadocs>
                <!-- Avoid type mvn eclipse:eclipse -Dwtpversion=2.0 -->
                <wtpversion>2.0</wtpversion>
            </configuration>
        </plugin>
        <!--Set JDK Compiler Level -->
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <!-- <version>2.3.2</version> 3.3 -->
            <version>3.5.1</version>
            <configuration>
                <source>${jdk.version}</source>
                <target>${jdk.version}</target>
            </configuration>
        </plugin>
            <!-- For Maven Tomcat Plugin -->
        <plugin>
            <groupId>org.apache.tomcat.maven</groupId>
            <artifactId>tomcat7-maven-plugin</artifactId>
            <version>2.2</version>
            <configuration>
                <path>/CounterWebApp</path>
            </configuration>
        </plugin>
    </plugins>
</build>

从 cmd 行运行 tomcat： mvn tomcat:运行

注意：你应该停止在eclipse中运行的tomcat服务器。

这个对我有用。