如何为 spring 配置 web.xml

Question

I am new to spring Framework and having problem with linking/configuring springframework through web.xml. I am getting below error when running my app.

Error:

HTTP Status 500 - Error instantiating servlet class org.springframework.web.servlet.DispatcherServlet


    type Exception report

    message Error instantiating servlet class org.springframework.web.servlet.DispatcherServlet

    description The server encountered an internal error (Error instantiating servlet class org.springframework.web.servlet.DispatcherServlet) that prevented it from fulfilling this request.

    exception 

    javax.servlet.ServletException: Error instantiating servlet class org.springframework.web.servlet.DispatcherServlet
        org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
        org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
        org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
        org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
        org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1001)
        org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585)
        org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
        java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        java.lang.Thread.run(Unknown Source)


    root cause 

    java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet
        org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1711)
        org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1556)
        org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
        org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
        org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
        org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
        org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1001)
        org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:585)
        org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
        java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        java.lang.Thread.run(Unknown Source)

Apparently, it could not find class org.springframework.web.servlet.DispatcherServlet in the Libraries. However, I dont know how to tell web.xml where to look for this class.

web.xml

    <?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" 
             xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" 
             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>
            <servlet-name>DispatcherSample</servlet-name>
            <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        </servlet>

        <servlet-mapping>
            <servlet-name>DispatcherSample</servlet-name>
            <url-pattern>/PlayField.html</url-pattern>
        </servlet-mapping>

      <welcome-file-list>
        <welcome-file>index.html</welcome-file>
        <welcome-file>Welcome.html</welcome-file>
      </welcome-file-list>

    </web-app>

DispatcherSample-servlet.xml

    <?xml version="1.0" encoding="UTF-8"?>

    <beans xmlns="http://www.springframework.org/schema/beans"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

        <bean id="handlerMapping" class="org.springframework.web.servlet.handler.SimpleUrlHandlerMapping">  
            <property name="mappings">
                <props>
                    <prop key="/PlayField.html">playfieldController</prop>
                </props>    
            </property>
        </bean>

        <bean id="playfieldController" class="demos.PlayfieldController"/>

    </beans>

Answer 1

java.lang.ClassNotFoundException: org.springframework.web.servlet.DispatcherServlet

You must add spring-webmvc.jar to your CLASSPATH (most likely to /WEB-INF/lib directory). The rest of your configuration seems fine.