请求的资源 [projectname/servlet] 不可用

Question

这是我的项目结构：- [1]: https://i.stack.imgur.com/ootY1.png

我的问题是每当我运行我在服务器上的项目时，都会出现 HTTP 状态 404 错误。这是我从服务器收到的错误：-

The requested resource [/Doctor_Appointment_Application/Regis] is not available

我正在使用注释来注册我的 servlet，但我的 web.xml.

中只有一个欢迎文件

Web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="4.0"
    xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee 
   http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd">
    <display-name>User Login</display-name>
    <session-config>
        <session-timeout>30</session-timeout>
    </session-config>
    <welcome-file-list>
        <welcome-file>/JSP/login.jsp</welcome-file>
    </welcome-file-list>
</web-app>

我的注册 Servlet：-

package com.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.bean.RegisBean;
import com.dao.RegisDao;

@WebServlet("/Regis")
public class Regis extends HttpServlet {
    private static final long serialVersionUID = 1L;

    public Regis() {

    }

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String fullname=request.getParameter("fullname");
        String email=request.getParameter("email");
        String username=request.getParameter("username");
        String password=request.getParameter("password");
        long mobile= Long.parseLong(request.getParameter("mobile"));
        String address=request.getParameter("address");
        String identity=request.getParameter("radio");
        String specialisation=request.getParameter("special");
        String degree=request.getParameter("degree");
        String exp=request.getParameter("exp");
        String fees=request.getParameter("fees");
        
        RegisBean regisBean=new RegisBean();
        regisBean.setFullname(fullname);
        regisBean.setEmail(email);
        regisBean.setUsername(username);
        regisBean.setPassword(password);
        regisBean.setMobile(mobile);
        regisBean.setAddress(address);
        regisBean.setIdentity(identity);

        if(identity.equals("Doctor")) {
            regisBean.setSpecialiasation(specialisation);
            regisBean.setDegree(degree);
            regisBean.setExperience(exp);
            regisBean.setFees(fees);
        }
        
        RegisDao dao=new RegisDao();
        String userRegistered=dao.registerUser(regisBean);
        if(userRegistered.equals("SUCCESS"))
            request.getRequestDispatcher("/JSP/conf.jsp").forward(request, response);
        else {
            request.setAttribute("errMessage", userRegistered);
            request.getRequestDispatcher("/JSP/register.jsp").forward(request, response);
        }
    }
}

编辑 1：

Register.jsp:-

<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Registration Page</title>
<style type="text/css">
<%-- <%@include file="/CSS/register.css"%> --%>
<%@include file="/CSS/regis.css"%>
</style>
<script src='https://kit.fontawesome.com/a076d05399.js'></script>
<script>
function validate() {
        var password = document.form.password.value;
        var confpassword = document.form.confpassword.value;

/*      if (password.length < 6) {
            alert("Password must be at least 6 characters long.");
            return false;
        } else */ if (password != confpassword) {
            alert("Confirm Password should match with the Password");
            return false;
        }
    }

 </script>
</head>
<body>
    <form name="form" action="<%=request.getContextPath() %>/Regis" method="post" onsubmit="return validate()">
        Full Name: <input type="text" name="fullname" required>
        <br>
        <br> 
        Email: <input type="text" name="email" required>
        <br>
        <br> 
        Username: <input type="text" name="username" required> 
        <br>
        <br> 
        Password: <input type="password" name="password" required> 
        <br>
        <br> 
        Confirm Password: <input type="password" name="confpassword" required>
        <br>
        <br>
        Mobile Number: <input type="number" name="mobile" required>
        <br>
        <br>
        Address: <input type="text" name="address" required>
        <br>
        <br>    
        Identity: &nbsp; Doctor <input type="radio" name="radio" value="Doctor" required>
        <div class="reveal">
            Specialisation: <select name="special" class="require-if-active">
                <option selected disabled>Choose...</option> 
                <option value="Allergist">Allergist</option>
                <option value="Anesthesiologist">Anesthesiologist</option>
                <option value="Cardiologist">Cardiologist</option>
                <option value="Dermatologist">Dermatologist</option>
                <option value="Endocrinologist">Endocrinologist</option>
                <option value="Gastroenterologist">Gastroenterologist</option>
                <option value="Hematologist">Hematologist</option>
                <option value="Immunologist">Immunologist</option>
                <option value="Internist">Internist</option>
                <option value="Neurologist">Neurologist</option>
                <option value="Pulmonologist">Pulmonologist</option>
                <option value="Oncologist">Oncologist</option>
            </select>
            <br>
            <br>
            Degree: <select name="degree" class="require-if-active">
                <option selected disabled>Choose...</option> 
                <option value="MBBS">MBBS</option>
                <option value="BDS">BDS</option>
                <option value="BAMS">BAMS</option>
                <option value="BUMS">BUMS</option>
                <option value="BHMS">BHMS</option>
                <option value="BYNS">BYNS</option>
                <option value="B.V.Sc & AH">B.V.Sc & AH</option>
            </select>
            <br>
            <br>
            Experience: <input type="number" name="exp" class="require-if-active">
            <br>
            <br>
            Fees: <input type="number" name="fees" class="require-if-active">
        </div>
        Patient <input type="radio" name="radio" value="Patient" required>
        <span style="color: red"><%=(request.getAttribute("errMessage") == null) ? "" : request.getAttribute("errMessage")%></span>
        <br>
        <br> <input type="submit" value="Register">
    </form> 
</body>
</html>

编辑 2：

我只是想做一个实验，我所做的是创建另一个 jsp 文件和一个 servlet 来检查问题是否出在我的 jsp 和 servlet 文件中。所以同样的事情发生了，jsp 文件运行成功但是服务器在提交表单方法后无法找到 servlet。

感谢任何形式的帮助。

Answer 1

更新（基于问题中发布的更新）：

替换

<form name="form" action="<%=request.getContextPath() %>/Regis" method="post" onsubmit="return validate()">

和

<form name="form" action="Regis" method="post" onsubmit="return validate()">

因为 JSP 中的路径已经相对于上下文路径。

原回答：

您收到此错误的原因是默认情况下，服务器将请求作为 GET 而您没有在您的 servlet 中提供 doGet 的任何实现。如果您从 JSP/HTML 调用此 servlet，请务必提及 method="POST"。如果您尝试直接调用 servlet，您可以将 doPost 重命名为 doGet 或提供 doGet 的实现，例如

protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    doPost(request, response);
}

Answer 2

看到这个的人你好，我通过从我的构建路径中删除 mysqljdbc.auth.dll 解决了这个查询。这解决了我的问题，现在工作正常。如果您对 mysqljdbc.auth.dll 文件有问题，只需将其复制到 JDK 8 bin 文件夹中，它就可以正常工作。

请求的资源 [projectname/servlet] 不可用

The requested resource [projectname/servlet] is not available

java

jsp

servlet-3.0

server

tomcat9

更新（基于问题中发布的更新）：

原回答：