模拟Servlet的本质

---src
	---web.properties
	---javax.servlet
		---Servlet
	---web
		---Tomcat
	---service
	    ---UserListServlet
	    ---UserLoginServlet

• web.properties

/aaa=service.UserListServlet
/bbb=service.UserLoginServlet

• Servlet

package javax.servlet;


public interface Servlet {
    void service();
}

• Tomcat

package web;

import javax.servlet.Servlet;
import java.util.ResourceBundle;
import java.util.Scanner;


public class Tomcat {
    public static void main(String[] args) throws ClassNotFoundException, InstantiationException, IllegalAccessException {
        System.out.println("Tomcat启动了....");
        Scanner s = new Scanner(System.in);
        System.out.print("请输入访问路径：");
        String path = s.nextLine();
        ResourceBundle bundle = ResourceBundle.getBundle("web");
        String resource = bundle.getString(path);
        Class clazz = Class.forName(resource);
        Object obj = clazz.newInstance();
        Servlet servlet = (Servlet) obj;
        servlet.service();
    }
}

• UserListServlet

package service;

import javax.servlet.Servlet;


public class UserListServlet implements Servlet {
    @Override
    public void service() {
        System.out.println("UserListServlet的service方法调用了！");
    }
}

• UserLoginServlet

package service;

import javax.servlet.Servlet;


public class UserLoginServlet implements Servlet {
    @Override
    public void service() {
        System.out.println("UserLoginServlet的service方法调用了！");
    }
}