HelloWorld Servlet中的Tomcat 404 classNotFoundException

Question

我看到了大多數類似的問題，並嘗試了大多數解決方案，但是沒有任何效果對我有用！

我對Java EE完全Java EE ，這是我的第一個servlet。

這是我的servlet，它位於： C:\\tomcat\\webapps\\jspbook\\WEB-INF\\classes

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HelloWorld extends HttpServlet {

@Override
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {

    response.setContentType("text/html");
    PrintWriter out = response.getWriter();

    out.println("<html>");
    out.println("<head>");
    out.println("<title> hello World Title </title>");
    out.println("</head>");
    out.println("<body>");
    out.println("<h1> Hello To World in body!</h1>");
    out.println("</body>");
    out.println("</html>");
   }
}

這是C:\\tomcat\\webapps\\jspbook\\WEB-INF web.xml文件

 <servlet>
    <servlet-name>HelloWorld</servlet-name>
    <servlet-class>HelloWorld</servlet-class>
 </servlet>

 <servlet-mapping>
    <servlet-name>HelloWorld</servlet-name>
    <url-pattern>/HelloWorld</url-pattern>
 </servlet-mapping> 


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

</web-app>

現在，當我重新啟動tomcat時，嘗試http://127.0.0.1:8080/jspbook/HelloWorld

第一次，這是我的第一個錯誤：

type Exception report

message Error instantiating servlet class HelloWorld

description The server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: Error instantiating servlet class HelloWorld
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2462)
    org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2451)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:722)

root cause

java.lang.ClassNotFoundException: HelloWorld
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1720)
    org.apache.catalina.loader.WebappClassLoader.loadClass(WebappClassLoader.java:1571)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:503)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
    org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:950)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:421)
    org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1070)
    org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:611)
    org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.doRun(AprEndpoint.java:2462)
    org.apache.tomcat.util.net.AprEndpoint$SocketProcessor.run(AprEndpoint.java:2451)
    java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1110)
    java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:603)
    org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    java.lang.Thread.run(Thread.java:722)

當我重新加載頁面時，這是我的第二個錯誤：

HTTP Status 404 -

type Status report

message

description The requested resource is not available.

我的代碼有什么問題？

更新：

我創建了一個程序包，並將其命名為com.jspbook ，並將其放在此處C:\\tomcat\\webapps\\jspbook\\WEB-INF\\classes\\com\\jspbook\\HelloWorld.java

package com.jspbook;

import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class HelloWorld extends HttpServlet {

    @Override
    public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
        response.setContentType("text/html");
        PrintWriter out = response.getWriter();

        out.println("<html>");
        out.println("<head>");
        out.println("<title> hello World Title </title>");
        out.println("</head>");
        out.println("<body>");
        out.println("<h1> Hello To World in body! </h1>");
        out.println("</body>");
        out.println("</html>");
    }
}

web.xml在這里： C:\\tomcat\\webapps\\jspbook\\WEB-INF\\web.xml

<web-app xmlns="http://java.sun.com/xml/ns/j2ee" version="2.4">

 <servlet>
    <servlet-name>HelloWorld</servlet-name>
    <servlet-class>com.jspbook.HelloWorld</servlet-class>
 </servlet>

 <servlet-mapping>

    <servlet-name>HelloWorld</servlet-name>
    <url-pattern>/HelloWorld</url-pattern>

 </servlet-mapping> 



<welcome-file-list>

<welcome-file> welcome.html </welcome-file>

</welcome-file-list>

</web-app>

我嘗試http://127.0.0.1:8080/jspbook/HelloWorld但出現相同的錯誤！

（根本沒有編譯的類文件）

Answer 1

請將servlet放在一個包中。 容器無法從默認包中加載類。

HelloWorld Servlet中的Tomcat 404 classNotFoundException

問題描述

1 個解決方案

解決方案1
1 已采納 2014-11-21 18:40:31

HelloWorld Servlet中的Tomcat 404 classNotFoundException

問題描述

1 個解決方案

解決方案1 1 已采納 2014-11-21 18:40:31

解決方案1
1 已采納 2014-11-21 18:40:31