import java.io.File;
import java.io.FileOutputStream;
/**
 * @Author: Manitozhang
 * @Data: 2019/1/9 16:51
 * @Email: manitozhang@foxmail.com
 *
 * 文件工具类
 */
public class FileUtil {
    public static void uploadFile(byte[] file, String filePath, String fileName) throws Exception {
        File targetFile = new File(filePath);
        if(!targetFile.exists()){
            targetFile.mkdirs();
        }
        FileOutputStream out = new FileOutputStream(filePath+fileName);
        out.write(file);
        out.flush();
        out.close();
    }
}

@Resource
    HttpServletRequest request;
    //处理文件上传
    @RequestMapping(value="/testuploadimg", method = RequestMethod.POST)
    public @ResponseBody String uploadImg(@RequestParam("file") MultipartFile file) {
        String fileName = file.getOriginalFilename();
        //设置文件上传路径
        String filePath = request.getSession().getServletContext().getRealPath("imgupload/");
        try {
            FileUtil.uploadFile(file.getBytes(), filePath, fileName);
            return "上传成功";
        } catch (Exception e) {
            return "上传失败";
        }
    }