xml方式定义

示例

<?xml version="1.0" encoding="UTF-8"?>
<web-app 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"
         version="4.0"
         metadata-complete="false">

    <display-name>Archetype Created Web Application</display-name>
    <servlet>
        <display-name>HelloServlet</display-name>
        <servlet-name>HelloServlet</servlet-name>
        <servlet-class>org.zz.servlet.HelloServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>HelloServlet</servlet-name>
        <url-pattern>/hello</url-pattern>
    </servlet-mapping>
</web-app>

package org.zz.servlet;

import jakarta.servlet.*;

import java.io.IOException;

public class HelloServlet implements Servlet {
    @Override
    public void init(ServletConfig servletConfig) throws ServletException {
        System.out.println("=== " + this.getClass().getName() + " init() ===");
    }

    @Override
    public ServletConfig getServletConfig() {
        return null;
    }

    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        System.out.println("=== " + this.getClass().getName() + " service() ===");
    }

    @Override
    public String getServletInfo() {
        return null;
    }

    @Override
    public void destroy() {
        System.out.println("=== " + this.getClass().getName() + " destroy() ===");
    }
}