Java HTTP 状态 500 错误实例化 servlet 类
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HTTP Status 500 Error instantiating servlet class
提问by jssmkp
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/
我正在编写一个 Web 应用程序并将其部署到 apache tomcat Web 容器。我遵循来自http://cse.csusb.edu/turner/java_web_programming/servlets/的简单教程
and then end up getting this error. I am pasting snippets of and web.xml, website.xml and my code files respectively.
然后最终得到这个错误。我分别粘贴和 web.xml、website.xml 和我的代码文件的片段。
Structure:
结构：
web.xml:
网页.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
HomeServlet.java
package website.web;
打包网站.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:
错误：
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)
采纳答案by Oleg Baranenko
I think somethin wrong in this section:
我认为本节有些不对劲：
<servlet-class>website.web.HomeServlet</servlet-class>
Instead try:
而是尝试：
<servlet-class>website.HomeServlet</servlet-class>
回答by JHH
First of all, your web.xml lists TestServlet as the class name for your server, as opposed to HomeServlet.
首先，您的 web.xml 将 TestServlet 列为您的服务器的类名，而不是 HomeServlet。
Second, it seems that although your HomeServlet class is in package website.web, it's physically located in a folder called website, not website/web. I would be surprised to see this even compile correctly?
其次，虽然您的 HomeServlet 类在包 website.web 中，但它实际上位于名为 website 而不是 website/web 的文件夹中。我会惊讶地看到这甚至可以正确编译？
