UploadController.java

package com.liferon.boot2demo;

import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.springframework.core.io.Resource;
import org.springframework.core.io.UrlResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.ResponseEntity;
import org.springframework.util.StringUtils;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

/**
 *
 * @author olanrewaju.ebenezer
 */
@RestController
public class UploadController {

    private final String uploadFolder = "uploads";
    private final Path rootLocation;

    public UploadController() throws IOException {
        rootLocation = Paths.get(uploadFolder);
        if (Files.notExists(rootLocation)) {
            try {
                Files.createDirectories(rootLocation);
            } catch (IOException ex) {
                System.err.println("IOException: " + ex.getMessage());
                throw ex;
                //Logger.getLogger(UploadController.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

    @GetMapping("/pictures/{filename:.+}")
    @ResponseBody
    public ResponseEntity<Resource> serveFile(@PathVariable String filename) {

        Path path = rootLocation.resolve(filename);
        Resource file = null;
        try {
            file = new UrlResource(path.toUri());
        } catch (MalformedURLException ex) {
            Logger.getLogger(UploadController.class.getName()).log(Level.SEVERE, null, ex);
        }
        return ResponseEntity.ok().header(HttpHeaders.CONTENT_DISPOSITION,
                "attachment; filename=\"" + file.getFilename() + "\"").body(file);
    }

    @PostMapping("/api/upload")
    public ResponseEntity<?> handleFileUpload(@RequestParam("picture") MultipartFile picture) {
        String filename = StringUtils.cleanPath(picture.getOriginalFilename());

        try (InputStream inputStream = picture.getInputStream()) {
            Files.copy(inputStream, this.rootLocation.resolve(filename),
                    StandardCopyOption.REPLACE_EXISTING);
        } catch (IOException ex) {
            Logger.getLogger(UploadController.class.getName()).log(Level.SEVERE, null, ex);
        }

        return ResponseEntity.ok("File uploaded successfully");
    }
}