## MULTIPART (MultipartProperties)

# Enable multipart uploads

spring.servlet.multipart.enabled=true

# Threshold after which files are written to disk.

spring.servlet.multipart.file-size-threshold=2KB

# Max file size.

spring.servlet.multipart.max-file-size=200MB

# Max Request Size

spring.servlet.multipart.max-request-size=215MB

​

## File Storage Properties

# All files uploaded through the REST API will be stored in this directory

file.upload-dir=/Users/callicoder/uploads

package com.example.filedemo.controller;

​

import com.example.filedemo.payload.UploadFileResponse;

import com.example.filedemo.service.FileStorageService;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import org.springframework.beans.factory.annotation.Autowired;

import org.springframework.core.io.Resource;

import org.springframework.http.HttpHeaders;

import org.springframework.http.MediaType;

import org.springframework.http.ResponseEntity;

import org.springframework.web.bind.annotation.*;

import org.springframework.web.multipart.MultipartFile;

import org.springframework.web.servlet.support.ServletUriComponentsBuilder;

import javax.servlet.http.HttpServletRequest;

import java.io.IOException;

import java.util.Arrays;

import java.util.List;

import java.util.stream.Collectors;

​

@RestController

public class FileController {

​

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

​

    @Autowired

    private FileStorageService fileStorageService;

    @PostMapping("/uploadFile")

    public UploadFileResponse uploadFile(@RequestParam("file") MultipartFile file) {

        String fileName = fileStorageService.storeFile(file);

​

        String fileDownloadUri = ServletUriComponentsBuilder.fromCurrentContextPath()

                .path("/downloadFile/")

                .path(fileName)

                .toUriString();

​

        return new UploadFileResponse(fileName, fileDownloadUri,

                file.getContentType(), file.getSize());

    }

​

    @PostMapping("/uploadMultipleFiles")

    public List<UploadFileResponse> uploadMultipleFiles(@RequestParam("files") MultipartFile[] files) {

        return Arrays.asList(files)

                .stream()

                .map(file -> uploadFile(file))

                .collect(Collectors.toList());

    }

​

    @GetMapping("/downloadFile/{fileName:.+}")

    public ResponseEntity<Resource> downloadFile(@PathVariable String fileName, HttpServletRequest request) {

        // Load file as Resource

        Resource resource = fileStorageService.loadFileAsResource(fileName);

​

        // Try to determine file's content type

        String contentType = null;

        try {

            contentType = request.getServletContext().getMimeType(resource.getFile().getAbsolutePath());

        } catch (IOException ex) {

            logger.info("Could not determine file type.");

        }

​

        // Fallback to the default content type if type could not be determined

        if(contentType == null) {

            contentType = "application/octet-stream";

        }

​

        return ResponseEntity.ok()

                .contentType(MediaType.parseMediaType(contentType))

                .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"")

                .body(resource);

    }

}

package com.example.filedemo.property;

​

import org.springframework.boot.context.properties.ConfigurationProperties;

​

@ConfigurationProperties(prefix = "file")

public class FileStorageProperties {

    private String uploadDir;

​

    public String getUploadDir() {

        return uploadDir;

    }

​

    public void setUploadDir(String uploadDir) {

        this.uploadDir = uploadDir;

    }

}

package com.example.filedemo;

​

import com.example.filedemo.property.FileStorageProperties;

import org.springframework.boot.SpringApplication;

import org.springframework.boot.autoconfigure.SpringBootApplication;

import org.springframework.boot.context.properties.EnableConfigurationProperties;

​

@SpringBootApplication

@EnableConfigurationProperties({

        FileStorageProperties.class

})

public class FileDemoApplication {

​

    public static void main(String[] args) {

        SpringApplication.run(FileDemoApplication.class, args);

    }

}