springBoot上传文件时加上拦截器MultipartFile报空问题解决方法

使用springboot2.0实现上传文件MultipartFile报空，找了一下午没有解决问题，最后思考是否是拦截器被拦截了，然后去掉拦截器配置，再次测试获取到了文件，确认拦截器问题后上网百度解决问题方法，今天早上找到解决办法：

添加配置类

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.multipart.MultipartResolver;
import org.springframework.web.multipart.commons.CommonsMultipartResolver;

@Configuration
public class UploadConfig {
    //显示声明CommonsMultipartResolver为mutipartResolver
    @Bean(name = "multipartResolver")
    public MultipartResolver multipartResolver() {
        CommonsMultipartResolver resolver = new CommonsMultipartResolver();
        resolver.setDefaultEncoding("UTF-8");
        //resolveLazily属性启用是为了推迟文件解析，以在在UploadAction中捕获文件大小异常
        resolver.setResolveLazily(true);
        resolver.setMaxInMemorySize(40960);
        //上传文件大小 5M 5*1024*1024
        resolver.setMaxUploadSize(5 * 1024 * 1024);
        return resolver;
    }

然后在sp