下载本地文件

package com.chen.controller;

import com.chen.utils.MultipartFileToFileUtils;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;


@Slf4j
@CrossOrigin
@RestController
@Api(tags = "文件下载测试")
@RequestMapping("/multipartFileController")
public class MultipartFileController {


    @ApiOperation("下载文件")
    @PostMapping("downloadFile")
    public String downloadFile(@RequestParam("file")MultipartFile file){
        return MultipartFileToFileUtils.saveMultipartFile(file, "src/main/resources/template/");
    }
}

package com.chen.utils;


import org.springframework.web.multipart.MultipartFile;

import java.io.*;
import java.util.UUID;

public class MultipartFileToFileUtils {

    /**
     * @param file
     * @param targetDirPath 存储MultipartFile文件的目标文件夹
     * @return 文件的存储的绝对路径
     */
    public static String saveMultipartFile(MultipartFile file, String targetDirPath) {

        File toFile = null;
        if (file.equals("") || file.getSize() <= 0) {
            return null;
        } else {

            /*获取文件原名称*/
            String originalFilename = file.getOriginalFilename();
            /*获取文件格式*/
            String fileFormat = originalFilename.substring(originalFilename.lastIndexOf("."));

            String uuid = UUID.randomUUID().toString().trim().replaceAll("-", "");
            toFile = new File(targetDirPath + File.separator + originalFilename);

            String absolutePath = null;
            try {
                absolutePath = toFile.getCanonicalPath();

                /*判断路径中的文件夹是否存在，如果不存在，先创建文件夹*/
                String dirPath = absolutePath.substring(0, absolutePath.lastIndexOf(File.separator));
                File dir = new File(dirPath);
                if (!dir.exists()) {
                    dir.mkdirs();
                }

                InputStream ins = file.getInputStream();

                inputStreamToFile(ins, toFile);
                ins.close();

            } catch (IOException e) {
                e.printStackTrace();
            }
            return absolutePath;
        }

    }

    //获取流文件
    private static void inputStreamToFile(InputStream ins, File file) {
        try {
            OutputStream os = new FileOutputStream(file);
            int bytesRead = 0;
            byte[] buffer = new byte[8192];
            while ((bytesRead = ins.read(buffer, 0, 8192)) != -1) {
                os.write(buffer, 0, bytesRead);
            }
            os.close();
            ins.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    /**
     * 删除本地临时文件
     *
     * @param file
     */
    public static void deleteTempFile(File file) {
        if (file != null) {
            File del = new File(file.toURI());
            del.delete();
        }
    }

}