Exception : java.lang.ClassNotFoundException: javax.servlet.http.HttpServletRequest when running Servlet [duplicate]

问题

I am working on a simple Upload JSP and Servlet tutorial outlined here :

Upload Tutorial

I have the system coded and my webpage finished but I am getting errors when running the application. When I click on the upload button, such as :

    SEVERE: Servlet.service() for servlet [UploadServlet] in context with path [/Test] threw exception [Servlet execution threw an exception] with root cause
java.lang.ClassNotFoundException: javax.servlet.http.HttpServletRequest
    at java.net.URLClassLoader$1.run(URLClassLoader.java:366)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at org.apache.commons.fileupload.servlet.ServletFileUpload.isMultipartContent(ServletFileUpload.java:68)
    at com.dell.UploadServlet.doPost(UploadServlet.java:45)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:724)

The tomcat page I'm being directed too looks as follows :

Error Picture

Anybody know what I've done wrong? Thanks

回答1:

You forgot/missed to add the apache common fileupload jar

 at org.apache.commons.fileupload.servlet.ServletFileUpload.
                     isMultipartContent(ServletFileUpload.java:68)

Check your lib/maven jar structure.

回答2:

I had a similar exception - different circumstances, but in my case, servlet-api.jar was clearly where it should be $CATALINA_HOME/lib/, however I installed jars that were compiled against a different servlet-api.jar and produced this exception:

java.lang.NoClassDefFoundError: javax/servlet/http/HttpServlet

The quick fix was to use the servlet-api.jar the servlets were originally compiled with, though in production I'd recommend recompiling your servlet instead of replacing tomcat's core jars.

来源：https://stackoverflow.com/questions/18082344/exception-java-lang-classnotfoundexception-javax-servlet-http-httpservletrequ

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java

java-ee

Tomcat

servlets

apache-commons