Eclipse似乎未编译servlet，从而导致java.lang.ClassNotFoundException [英] Eclipse does not seem to compile servlet, causing java.lang.ClassNotFoundException

问题描述

目前，我正在使用Ubuntu 12.04LTS，Eclipse IDE和Apache Tomcat 7.0.27，但我没有完成任务。

Currently I am using Ubuntu 12.04LTS , Eclipse IDE and Apache Tomcat 7.0.27 and I am not getting the job done.

我制作了一个简单的jsp页面 WebContent / index.jsp中的 index.jsp。我在程序包 com.pack.web中创建了一个名为 EmployeeClass的servlet。
在Jsp页面中，我有一个带有get方法和操作的表单，如下所示：

I made a simple jsp page "index.jsp" which is in "WebContent/index.jsp". I made a servlet called "EmployeeClass" which is inside the package "com.pack.web". In Jsp page I have a form with get method and a action as follow:

<form method="GET" action="hidden.do">

在web.xml中，我也有：

In web.xml I also have:

<servlet>
    <servlet-name>Searcher</servlet-name>
    <servlet-class>com.pack.web.EmployeeClass</servlet-class>
</servlet>
<servlet-mapping>
    <servlet-name>Searcher</servlet-name>
    <url-pattern>/hidden.do</url-pattern>
</servlet-mapping>

我制作了一个简单的servlet EmployeeClass，它在软件包中：

I made a simple servlet "EmployeeClass", it's in package:

package com.pack.web;

在此servlet中，我有一个doGet方法，如：

in this servlet I have a doGet method as:

protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    PrintWriter out = response.getWriter();
    out.println("Something is happening");
}

我终于然后运行了我的项目，并点击了提交按钮，砰此：

I finally then run my project and after hitting the submit button, bang I have this:

javax.servlet.ServletException: Error instantiating servlet class com.pack.web.EmployeeClass
    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:999)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
    java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    java.lang.Thread.run(Thread.java:662)

根本原因

java.lang.ClassNotFoundException: com.pack.web.EmployeeClass
    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:999)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
    org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
    java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    java.lang.Thread.run(Thread.java:662)

推荐答案

最后，在2周15小时和34分钟后，我找到了解决方案。通过打开显然被意外关闭的自动构建解决了该问题。

Finally at last after 2 weeks 15hrs and 34min I found the solution. The problem was solved by turning on automatic build which was apparently accidentally turned off.

Project->自动构建

Project -> Build Automatically

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