无法调用getBean（）

我在按步骤配置了ApplicationContext  context = new ClassPathXmlApplicationContext("spring.xml");

但是无法调用context.getBean(beanName);

我查找了资料，也修改了maven项目的ignore，勾除了我这个web maven

我在pom.xml中也引用类service 的maven项目，但是都不行

请老师指点一下

package com.imooc.hospital.global;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import javax.servlet.GenericServlet;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class DispatcherServlet extends GenericServlet {

    private ApplicationContext context;

    @Override
    public void init() throws ServletException {
        super.init();
        context = new ClassPathXmlApplicationContext("spring.xml");
    }

    @Override
    public void service(ServletRequest servletRequest, ServletResponse servletResponse) throws ServletException, IOException {
        HttpServletRequest request = (HttpServletRequest) servletRequest;
        HttpServletResponse response = (HttpServletResponse) servletResponse;

        /**
         * /user/add.do     /login.do
         * userController
         * public void add(HttpServletRequest request,HttpServletResponse response)
         *
         */

        //提取url并且去掉第一个“/”
        String path = request.getServletPath().substring(1);
        String beanName = null;
        String methodName = null;
        int index = path.indexOf("/");

        if (index != -1) {
            beanName = path.substring(0, index) + "Controller";
            methodName = path.substring(index + 1, path.indexOf(".do"));
        } else {
            beanName = "selfController";
            methodName = path.substring(0, path.indexOf(".do"));
        }
        Object obj = context.getBean(beanName);
    }
}