老师你好，
MvcConfiguration配置中

    /**
     * 定义默认的请求处理器
     */
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

这个配置出错，去掉这个就没异常出现，很焦虑，望老师帮忙看一下，谢谢。
这是代码

package com.imooc.o2o.config.web;

import javax.servlet.ServletException;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.web.servlet.ServletRegistrationBean;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;
import org.springframework.web.servlet.ViewResolver;
import org.springframework.web.servlet.config.annotation.*;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

import com.google.code.kaptcha.servlet.KaptchaServlet;

/**
 * 开启Mvc,自动注入spring容器。 WebMvcConfigurerAdapter：配置视图解析器
 * 当一个类实现了这个接口（ApplicationContextAware）之后，这个类就可以方便获得ApplicationContext中的所有bean
 *
 * @author xiangze
 *
 */
@Configuration
// 等价于<mvc:annotation-driven/>
@EnableWebMvc
public class MvcConfiguration extends WebMvcConfigurerAdapter implements ApplicationContextAware {
    // Spring容器
    private ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

    /**
     * 静态资源配置
     *
     * @param registry
     */
    @Override
    public void addResourceHandlers(ResourceHandlerRegistry registry) {
         registry.addResourceHandler("/resources/**").addResourceLocations("classpath:/resources/");
//        registry.addResourceHandler("/upload/**").addResourceLocations("file:/Users/baidu/work/image/upload/");
    }

    /**
     * 定义默认的请求处理器
     */
    @Override
    public void configureDefaultServletHandling(DefaultServletHandlerConfigurer configurer) {
        configurer.enable();
    }

    /**
     * 创建viewResolver
     *
     * @return
     */
    @Bean(name = "viewResolver")
    public ViewResolver createViewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        // 设置Spring 容器
        viewResolver.setApplicationContext(this.applicationContext);
        // 取消缓存
        viewResolver.setCache(false);
        // 设置解析的前缀
        viewResolver.setPrefix("/WEB-INF/html/");
        // 设置试图解析的后缀
        viewResolver.setSuffix(".html");
        return viewResolver;
    }

    /**
     * 文件上传解析器
     *
     * @return
     */
    @Bean(name = "multipartResolver")
    public CommonsMultipartResolver createMultipartResolver() {
        CommonsMultipartResolver multipartResolver = new CommonsMultipartResolver();
        multipartResolver.setDefaultEncoding("utf-8");
        // 1024 * 1024 * 20 = 20M
        multipartResolver.setMaxUploadSize(20971520);
        multipartResolver.setMaxInMemorySize(20971520);
        return multipartResolver;
    }
}