HTTP状态500错误实例化servlet类 [英] HTTP Status 500 Error instantiating servlet class
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问题描述
我写一个web应用程序，并将其部署到Apache Tomcat Web容器。我遵循 http://cse.csusb.edu/turner/java_web_programming/servlets/一个简单的教程
，然后最终得到这个错误。我分别粘贴的片段和web.xml，website.xml和我的code文件。
结构：
web.xml中：
＆LT;？XML版本=1.0＆GT？;
＆LT; web应用程序
的xmlns =http://java.sun.com/xml/ns/j2ee
XMLNS：XSI =http://www.w3.org/2001/XMLSchema-instance
XSI：的schemaLocation =http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd
版本=2.4＆GT;
＆LT;＆servlet的GT;
＆LT; servlet的名称＆gt;＆回家LT; / servlet的名称＆gt;
＆LT;的servlet类＆GT; website.web.HomeServlet＆LT; / servlet的类＆GT;
＆LT; / servlet的＆GT;
＆LT; Servlet映射＆GT;
＆LT; servlet的名称＆gt;＆回家LT; / servlet的名称＆gt;
＆LT; URL模式＆GT; /家居与LT; / URL模式＆GT;
＆LT; / Servlet映射＆GT;
＆LT; / web-app的＆GT;
HomeServlet.java
包website.web;
进口java.io.IOException异常;
进口的java.io.PrintWriter;
进口javax.servlet.ServletException;
进口javax.servlet.ServletRequest;
进口javax.servlet.ServletResponse;
进口javax.servlet.http.HttpServlet;
进口javax.servlet.http.HttpServletRequest;
进口javax.servlet.http.HttpServletResponse;公共类HomeServlet延伸的HttpServlet { @覆盖
保护无效的doGet（HttpServletRequest的REQ，HttpServletResponse的RESP）
抛出了ServletException，IOException异常{
为PrintWriter作家= resp.getWriter（）;
writer.println（＆LT; H1＆GT;的Hello，World＆LT;！/ H1＆gt;中）;
}
}
错误：
HTTP状态500 - 错误实例化servlet类website.web.HomeServlet类型异常报告消息错误实例化servlet类website.web.HomeServlet说明服务器遇到了$ P $履行这一要求pvented它内部错误。例外javax.servlet.ServletException：错误实例化servlet类website.web.HomeServlet
org.apache.catalina.authenticator.AuthenticatorBase.invoke（AuthenticatorBase.java:502）
org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:79）
org.apache.catalina.valves.AbstractAccessLogValve.invoke（AbstractAccessLogValve.java:610）
org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:518）
org.apache.coyote.http11.AbstractHttp11Processor.process（AbstractHttp11Processor.java:1091）
org.apache.coyote.AbstractProtocol $ AbstractConnectionHandler.process（AbstractProtocol.java:668）
org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
org.apache.tomcat.util.net.NioEndpoint $ SocketProcessor.doRun（NioEndpoint.java:1517）
org.apache.tomcat.util.net.NioEndpoint $ SocketProcessor.run（NioEndpoint.java:1474）
java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1142）
java.util.concurrent.ThreadPoolExecutor中的$ Worker.run（ThreadPoolExecutor.java:617）
org.apache.tomcat.util.threads.TaskThread $ WrappingRunnable.run（TaskThread.java:61）
java.lang.Thread.run（Thread.java:745）
根本原因抛出java.lang.ClassNotFoundException：website.web.HomeServlet
org.apache.catalina.loader.WebappClassLoaderBase.loadClass（WebappClassLoaderBase.java:1305）
org.apache.catalina.loader.WebappClassLoaderBase.loadClass（WebappClassLoaderBase.java:1157）
org.apache.catalina.authenticator.AuthenticatorBase.invoke（AuthenticatorBase.java:502）
org.apache.catalina.valves.ErrorReportValve.invoke（ErrorReportValve.java:79）
org.apache.catalina.valves.AbstractAccessLogValve.invoke（AbstractAccessLogValve.java:610）
org.apache.catalina.connector.CoyoteAdapter.service（CoyoteAdapter.java:518）
org.apache.coyote.http11.AbstractHttp11Processor.process（AbstractHttp11Processor.java:1091）
org.apache.coyote.AbstractProtocol $ AbstractConnectionHandler.process（AbstractProtocol.java:668）
org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
org.apache.tomcat.util.net.NioEndpoint $ SocketProcessor.doRun（NioEndpoint.java:1517）
org.apache.tomcat.util.net.NioEndpoint $ SocketProcessor.run（NioEndpoint.java:1474）
java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1142）
java.util.concurrent.ThreadPoolExecutor中的$ Worker.run（ThreadPoolExecutor.java:617）
org.apache.tomcat.util.threads.TaskThread $ WrappingRunnable.run（TaskThread.java:61）
java.lang.Thread.run（Thread.java:745）
解决方案
我觉得事端错在本节：
＆LT;的servlet类＆GT; website.web.HomeServlet＆LT; / servlet的类＆GT;
而不是尝试：
＆LT;的servlet类＆GT; website.HomeServlet＆LT; / servlet的类＆GT;
I am writing a web app and deploying it to the apache tomcat web container. I follow a simple tutorial from http://cse.csusb.edu/turner/java_web_programming/servlets/
and then end up getting this error. I am pasting snippets of and web.xml, website.xml and my code files respectively.
Structure:
web.xml:
<?xml version="1.0"?>
<web-app
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee
http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"
version="2.4">
<servlet>
<servlet-name>home</servlet-name>
<servlet-class>website.web.HomeServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>home</servlet-name>
<url-pattern>/home</url-pattern>
</servlet-mapping>
</web-app>
HomeServlet.java
package website.web;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class HomeServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
PrintWriter writer = resp.getWriter();
writer.println("<h1>Hello, World!</h1>");
}
}
Error:
HTTP Status 500 - Error instantiating servlet class website.web.HomeServlet
type Exception report
message Error instantiating servlet class website.web.HomeServlet
description The server encountered an internal error that prevented it from fulfilling this request.
exception
javax.servlet.ServletException: Error instantiating servlet class website.web.HomeServlet
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1517)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1474)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
root cause
java.lang.ClassNotFoundException: website.web.HomeServlet
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1305)
org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1157)
org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:610)
org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:518)
org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1091)
org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:668)
org.apache.coyote.http11.Http11NioProtocol$Http11ConnectionHandler.process(Http11NioProtocol.java:223)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1517)
org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1474)
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
java.lang.Thread.run(Thread.java:745)
解决方案
I think somethin wrong in this section:
<servlet-class>website.web.HomeServlet</servlet-class>
Instead try:
<servlet-class>website.HomeServlet</servlet-class>
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