java - HTTP状态500-实例化servlet类com.controller.RegisterServlet时出错

我创建了一个jsp文件register.jsp，其中获取了用户的详细信息，并尝试将其保存在数据库中
RegisterServlet.java

package com.controller;

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;

import com.model.User;
import com.service.RegisterService;


public class RegisterServlet extends HttpServlet {

    public void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
     response.setContentType("text/html;charset=UTF-8");
     PrintWriter out = response.getWriter();
     String firstName = request.getParameter("firstName");
     String middleName = request.getParameter("middleName");
     String lastName = request.getParameter("lastName");
     String email = request.getParameter("email");
     String userId = request.getParameter("userId");
     String password = request.getParameter("password");
     User user = new User(firstName,middleName,lastName, email,userId, password);

     try {
         RegisterService registerService = new RegisterService();
         boolean result = registerService.register(user);
         out.println("<html>");
         out.println("<head>");
         out.println("<title>Registration Successful</title>");
         out.println("</head>");
         out.println("<body>");
         out.println("<center>");
         if(result){
             out.println("<h1>Thanks for Registering with us :</h1>");
             out.println("To login with new UserId and Password<a href=login.jsp>Click here</a>");
         }else{
             out.println("<h1>Registration Failed</h1>");
             out.println("To try again<a href=register.jsp>Click here</a>");
         }
         out.println("</center>");
         out.println("</body>");
         out.println("</html>");
     } finally {
         out.close();
     }

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.5" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
    <display-name>MVCApplication</display-name>
    <servlet>
        <display-name>LoginServlet</display-name>
        <servlet-name>LoginServlet</servlet-name>
        <servlet-class>com.controller.LoginServlet</servlet-class>
    </servlet>
    <servlet>
        <display-name>RegisterServlet</display-name>
        <servlet-name>RegisterServlet</servlet-name>
        <servlet-class>com.controller.RegisterServlet</servlet-class>
    </servlet>
    <servlet>
        <servlet-name>InsertDataItem</servlet-name>
        <servlet-class>com.controller.InsertDataItem</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>LoginServlet</servlet-name>
        <url-pattern>/LoginServlet</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>RegisterServlet</servlet-name>
        <url-pattern>/RegisterServlet</url-pattern>
    </servlet-mapping>
    <servlet-mapping>
        <servlet-name>InsertDataItem</servlet-name>
        <url-pattern>/InsertDataItem</url-pattern>
    </servlet-mapping>
    <welcome-file-list>
        <welcome-file>login.jsp</welcome-file>
    </welcome-file-list>
</web-app>

错误

**exception**
javax.servlet.ServletException: Error instantiating servlet class com.controller.RegisterServlet
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783)
    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434)
    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    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: com.controller.RegisterServlet
    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1285)
    org.apache.catalina.loader.WebappClassLoaderBase.loadClass(WebappClassLoaderBase.java:1119)
    org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:474)
    org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
    org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:624)
    org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:349)
    org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:783)
    org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
    org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:798)
    org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1434)
    org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
    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)

每当我提交我的详细信息以在数据库中注册时，都会出现此错误
弹出！。谁能帮帮我吗？？

最佳答案

您将需要确保RegisterServlet类实际上可用于servlet容器。

通常，在WEB-INF目录中，您将具有以下目录：

LIB
类

您需要确保该类在classes目录中可用，或者该类在lib目录中的JAR内部

关于java - HTTP状态500-实例化servlet类com.controller.RegisterServlet时出错，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/42807998/