import javax.servlet.*;

 import javax.servlet.annotation.WebServlet;

 import java.io.IOException;

 //@WebServlet(urlPatterns = "/demo")

 @WebServlet("/demo")

 public class ServletDemo implements Servlet {

     @Override

     public void init(ServletConfig servletConfig) throws ServletException {

     }

     @Override

     public ServletConfig getServletConfig() {

         return null;

     }

     @Override

     public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {

         System.out.println("servlet 3.0");

     }

     @Override

     public String getServletInfo() {

         return null;

     }

     @Override

     public void destroy() {

     }

 }

 //

 // Source code recreated from a .class file by IntelliJ IDEA

 // (powered by Fernflower decompiler)

 //

 package javax.servlet.annotation;

 import java.lang.annotation.Documented;

 import java.lang.annotation.ElementType;

 import java.lang.annotation.Retention;

 import java.lang.annotation.RetentionPolicy;

 import java.lang.annotation.Target;

 @Target({ElementType.TYPE})

 @Retention(RetentionPolicy.RUNTIME)

 @Documented

 public @interface WebServlet {

     String name() default "";          //相当于<Servlet-name>

     String[] value() default {};       //代表urlPatterns()属性配置

     String[] urlPatterns() default {}; //相当于<url-pattern>

     int loadOnStartup() default -1;    //相当于<load-on-startup>

     WebInitParam[] initParams() default {};

     boolean asyncSupported() default false;

     String smallIcon() default "";

     String largeIcon() default "";

     String description() default "";

     String displayName() default "";

 }