出现404报错

package com.imooc.servlet;

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

public class CalculateServlet extends HttpServlet {
    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        String num1 = request.getParameter("num1");
        String num2 = request.getParameter("num2");

        PrintWriter out = response.getWriter();
        out.println("<h1>Addition Calculator：</h1><br/>");
        out.println("<h1>Calculation result:"+(Integer.parseInt(num1)+Integer.parseInt(num2))+"</h1>");
    }
}

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>加法计算器</title>
</head>
<body>
<form action="/calculate">
    加数1：<input type="text" name="num1" style="margin:15px 0"/><br/>
    加数2：<input type="text" name="num2" style="margin:15px 0"/><br/>
    <button type="submit">计算</button><br/>
</form>
</body>
</html>

<servlet>
    <servlet-name>calculate</servlet-name>
    <servlet-class>com.imooc.servlet.CalculateServlet</servlet-class>
</servlet>

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

问题描述：

想知道如何解决404错误

杰码农 2021-11-22

源自：Web与Servlet基础 2-15 自由编程