springmvc中的上传文件报错

 下面是报错内容

org.springframework.beans.BeanInstantiationException: Failed to instantiate [org.springframework.web.multipart.MultipartFile]: Specified class is an interface

直接看Controller类：

package com.tjcu.controller;

import org.apache.commons.io.FilenameUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;
import java.util.UUID;

@Controller
@RequestMapping("file")
public class FileController {

    @RequestMapping("upload")
    public String fileUpload(MultipartFile upload, HttpServletRequest request) throws IOException {

        //获取原文件名
        String originalFilename = upload.getOriginalFilename();
        //上传文件的类型
        String contentType = upload.getContentType();
        //上传文件的大小
        long size = upload.getSize();
        
        System.out.println(originalFilename);
        System.out.println(contentType);
        System.out.println(size);

        //提取文件后缀名
        String extension = FilenameUtils.getExtension(upload.getOriginalFilename());
        String newFileName = UUID.randomUUID().toString().replace("-","")+"."+extension;

        System.out.println(newFileName);

        //调用业务 文件拷贝 将接收的文件放upload里
        String realPath = request.getSession().getServletContext().getRealPath("/upload");
        upload.transferTo(new File(realPath+"/"+newFileName));

        return "index";
    }
}

解决方法：

在MultipartFile  前面加上@RequestParam  

package com.tjcu.controller;

import org.apache.commons.io.FilenameUtils;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletRequest;
import java.io.File;
import java.io.IOException;
import java.util.UUID;

@Controller
@RequestMapping("file")
public class FileController {

    @RequestMapping("upload")
    public String fileUpload(@RequestParam MultipartFile upload, HttpServletRequest request) throws IOException {

        //获取原文件名
        String originalFilename = upload.getOriginalFilename();
        //上传文件的类型
        String contentType = upload.getContentType();
        //上传文件的大小
        long size = upload.getSize();
        
        System.out.println(originalFilename);
        System.out.println(contentType);
        System.out.println(size);

        //提取文件后缀名
        String extension = FilenameUtils.getExtension(upload.getOriginalFilename());
        String newFileName = UUID.randomUUID().toString().replace("-","")+"."+extension;

        System.out.println(newFileName);

        //调用业务 文件拷贝 将接收的文件放upload里
        String realPath = request.getSession().getServletContext().getRealPath("/upload");
        upload.transferTo(new File(realPath+"/"+newFileName));

        return "index";
    }
}

 直接传入MultipartFile，springmvc不能自动映射 上传文件到指定的参数中

@RequestParam  用于将指定的请求参数赋值给形参