Hello World Servlet执行遇404错误求助，已耗时超10小时未解决

无法成功运行这个Hello World Servlet，尝试各种方法耗时超10小时仍未解决，希望得到帮助。

HTML代码 #

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>lifelongterror</title>
</head>
<body>
<header><h1>This is a java web project #1</h1></header>
<form action="subtract" method="get">
<input type="submit">Click to say hello world.<br>
</form>
</body>
</html>

Servlet代码 #

import javax.servlet.annotation.*;
import java.io.*;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

@WebServlet(name="subtract", urlPatterns={"/subtract"})
class Serv3 extends HttpServlet{
    static final long serialVersionUID = 3535335;
    
    public void doGet(HttpServletRequest req, HttpServletResponse res) {
        try {
            PrintWriter p = res.getWriter();
            p.println("hello World");
        } catch(IOException e) {
            e.printStackTrace();
        }
    }
}

部署与测试情况 #

• Servlet类存放路径：src>main>java>package
• HTML文件位置：项目默认webapp目录
• 已完成服务器部署配置，但点击表单提交后始终返回404错误
• 已在Eclipse内置浏览器、Chrome、Microsoft Edge中测试，结果一致

内容的提问来源于stack exchange，提问作者Ronit Pandey