前端是：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>

使用spring mvc提供的类的方法上传文件

controller :

@RequestMapping(value = "/updatespringUpload")
public String springUpload(HttpServletRequest request) throws IllegalStateException, IOException
{
long startTime=System.currentTimeMillis();
//将当前上下文初始化给 CommonsMutipartResolver （多部分解析器）
CommonsMultipartResolver multipartResolver=new CommonsMultipartResolver(
request.getSession().getServletContext());
//检查form中是否有enctype="multipart/form-data"
if(multipartResolver.isMultipart(request))
{
//将request变成多部分request
MultipartHttpServletRequest multiRequest=(MultipartHttpServletRequest)request;
//获取multiRequest 中所有的文件名
Iterator iter=multiRequest.getFileNames();

        while(iter.hasNext())
        {
            //一次遍历所有文件
            MultipartFile file=multiRequest.getFile(iter.next().toString());
            if(file!=null)
            {
                String path="E:/springUpload"+file.getOriginalFilename();
                //上传
                file.transferTo(new File(path));
            }

        }

    }
    long  endTime=System.currentTimeMillis();
    System.out.println("方法三的运行时间："+String.valueOf(endTime-startTime)+"ms");
    return "/success";
}

报错内容是：
HTTP Status 500 - Request processing failed; nested exception is com.alibaba.fastjson.JSONException: toJSON error