配置 

import org.springframework.boot.web.servlet.MultipartConfigFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

import javax.servlet.MultipartConfigElement;

/**
 * 上传文件配置
 * @author yuhao
 */
@Configuration
public class MultipartConfig {
    @Bean
    public MultipartConfigElement multipartConfigElement() {
        MultipartConfigFactory factory = new MultipartConfigFactory();
        // 置文件大小限制 ,超出此大小页面会抛出异常信息//KB,MB
        factory.setMaxFileSize("100MB");
        // 设置总上传数据总大小
        factory.setMaxRequestSize("100MB");
        // 设置文件临时文件夹路径
        // factory.setLocation("E://test//");
        // 如果文件大于这个值，将以文件的形式存储，如果小于这个值文件将存储在内存中，默认为0
        // factory.setMaxRequestSize(0);
        return factory.createMultipartConfig();
    }
}

controller 

import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import io.swagger.annotations.ApiParam;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.*;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

@RestController
@Api(tags = "文件上传", description = "FileController")
@RequestMapping(value = "/file")
@SuppressWarnings("all")
public class FileController {
//    @Autowired
//    private imgService service;

    //获取主机端口
    @Value("${server.port}")
    private String port;
    //获取本机ip
    @Value("${server.host}")
    private String host;


    //图片存放根路径
    private String rootPath = "C:";
    //用户上传图片存放根目录下的子目录
    private String sonPath = "/file/";
    //日期目录
    private String datePath;
    //获取图片链接
    private String imgPath;

    private static final Logger logger = LoggerFactory.getLogger(FileController.class);

    @PostMapping(value = "/upload")
    @ApiOperation(value = "单文件上传")
    public Result upload(@RequestParam("file") MultipartFile file) {
        //返回上传的文件是否为空，即没有选择任何文件，或者所选文件没有内容。
        //防止上传空文件导致奔溃
        if (file.isEmpty()) {
            return fail("文件为空");
        }

        //获取本机IP
//        try {
//            host = InetAddress.getLocalHost().getHostAddress();
//        } catch (UnknownHostException e) {
//            logger.error("get server host Exception e:", e);
//        }

        // 获取文件名
        String fileName = file.getOriginalFilename();
        String suffixName = fileName.substring(fileName.lastIndexOf("."));

        if (Constants.SUFFIX_IMAGE.contains(suffixName.toLowerCase())) {
            sonPath = "/file/imgs/";
        }
        if (Constants.SUFFIX_AUDIO.contains(suffixName.toLowerCase())) {
            sonPath = "/file/audio/";
        }
        if (Constants.SUFFIX_VIDEO.contains(suffixName.toLowerCase())) {
            sonPath = "/file/video/";
        }

        logger.info("上传的文件名为：" + fileName);
        // 设置文件上传后的路径
        // 解决中文问题，liunx下中文路径，图片显示问题
        fileName = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date())
                + "-" + UUIDUtil.getUUID() + suffixName;

        datePath = new SimpleDateFormat("yyyyMMdd").format(new Date()) + "/";

        String filePath = rootPath + sonPath + datePath;

        logger.info("上传的文件路径" + filePath);
        logger.info("整个图片路径：" + "http://" + host + ":" + port + sonPath + datePath + fileName);
        //创建文件路径
        File dest = new File(filePath + fileName);

        imgPath = (host + ":" + port + sonPath + datePath + fileName).toString();

        // 检测是否存在目录
        if (!dest.getParentFile().exists()) {
            //假如文件不存在即重新创建新的文件已防止异常发生
            dest.getParentFile().mkdirs();
        }
        try {
            //transferTo（dest）方法将上传文件写到服务器上指定的文件
            file.transferTo(dest);
            //将链接保存到URL中
            //imgTest imgTest = service.add(new imgTest(), imgPath);

            return success((sonPath + datePath + fileName).toString());
        } catch (Exception e) {

            return fail("上传失败");
        }
    }

    @PostMapping(value = "/uploadBatch")
    @ApiOperation(value = "批量文件上传")
    public Result uploadBatch(@RequestParam("files") MultipartFile[] files, HttpServletRequest request) {
        //List<MultipartFile> files = ((MultipartHttpServletRequest) request).getFiles("file");
        BufferedOutputStream stream = null;
        List<String> result = new ArrayList<>();
        for (MultipartFile file : files) {

            if (!file.isEmpty()) {
                // 获取文件名
                String fileName = file.getOriginalFilename();
                String suffixName = fileName.substring(fileName.lastIndexOf("."));

                if (Constants.SUFFIX_IMAGE.contains(suffixName.toLowerCase())) {
                    sonPath = "/file/imgs/";
                }
                if (Constants.SUFFIX_AUDIO.contains(suffixName.toLowerCase())) {
                    sonPath = "/file/audio/";
                }
                if (Constants.SUFFIX_VIDEO.contains(suffixName.toLowerCase())) {
                    sonPath = "/file/video/";
                }

                logger.info("上传的文件名为：" + fileName);
                // 设置文件上传后的路径

                // 解决中文问题，liunx下中文路径，图片显示问题
                fileName = new SimpleDateFormat("yyyyMMddHHmmss").format(new Date())
                        + "-" + UUIDUtil.getUUID() + suffixName;

                datePath = new SimpleDateFormat("yyyyMMdd").format(new Date()) + "/";

                String filePath = rootPath + sonPath + datePath;
                logger.info("上传的文件路径" + filePath);
                logger.info("整个图片路径：" + host + ":" + port + sonPath + datePath + fileName);
                //创建文件路径
                File dest = new File(filePath + fileName);

                if (!dest.getParentFile().exists()) {
                    //假如文件不存在即重新创建新的文件已防止异常发生
                    dest.getParentFile().mkdirs();
                }

                try {
//                    byte[] bytes = file.getBytes();
//                    stream = new BufferedOutputStream(new FileOutputStream(dest));
//                    stream.write(bytes);
//                    stream.close();
                    //transferTo（dest）方法将上传文件写到服务器上指定的文件
                    file.transferTo(dest);
                    result.add((sonPath + datePath + fileName).toString());
                } catch (Exception e) {
                    stream = null;
                    return fail("You failed to upload " + " => " + e.getMessage());
                }
            } else {
                return fail("You failed to upload " + " because the file was empty.");
            }

        }
        return success(result);
    }


    //文件下载相关代码
    @GetMapping("/download")
    @ApiOperation(value = "文件下载")
    public ResponseEntity downloadFile(HttpServletRequest request, HttpServletResponse response,
                                       @ApiParam(value = "文件名", required = true) @RequestParam(name = "fileName", required = true) String fileName) {
        //String fileName = "aim_test.txt";// 设置文件名，根据业务需要替换成要下载的文件名
        if (fileName != null) {
            //设置文件路径
            String realPath = "C:\\imgs\\";
            File file = new File(realPath, fileName);
            if (file.exists()) {
                response.setContentType("application/force-download");// 设置强制下载不打开
                response.addHeader("Content-Disposition", "attachment;fileName=" + fileName);// 设置文件名
                byte[] buffer = new byte[1024];
                FileInputStream fis = null;
                BufferedInputStream bis = null;
                try {
                    fis = new FileInputStream(file);
                    bis = new BufferedInputStream(fis);
                    OutputStream os = response.getOutputStream();
                    /*int i = bis.read(buffer);
                    while (i != -1) {
                        os.write(buffer, 0, i);
                        i = bis.read(buffer);
                    }*/
                    int bytesRead = 0;
                    while ((bytesRead = bis.read(buffer)) != -1) {
                        os.write(buffer, 0, bytesRead);
                    }
                    System.out.println("success");
                    return null;
                } catch (Exception e) {
                    e.printStackTrace();
                } finally {
                    if (bis != null) {
                        try {
                            bis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                    if (fis != null) {
                        try {
                            fis.close();
                        } catch (IOException e) {
                            e.printStackTrace();
                        }
                    }
                }
            }
        }
        return null;
    }


}