Develop Reference

How to download and force the browser to save a file locally in one request?

I have an unusual task. I have to download the file and immediately force my browser to save it locally to disk?
Below, what I have written so far
#PostMapping("/uploadFile")
public String uploadFile(#RequestParam("file") MultipartFile file, RedirectAttributes redirectAttributes, Model model) {
if (file.isEmpty()) {
redirectAttributes.addFlashAttribute("errorMessage", "No file to upload.");
return "index";
}
if(getExtension(file.getOriginalFilename()).equals("XLS") || getExtension(file.getOriginalFilename()).equals("XLSX")) {
Path copyLocation = Paths
.get(UPLOAD_DIR + File.separator + StringUtils.cleanPath(file.getName()));
try {
Files.copy(file.getInputStream(), copyLocation, StandardCopyOption.REPLACE_EXISTING);
} catch (IOException e) {
e.printStackTrace();
}
redirectAttributes.addFlashAttribute("successMessage", "File upload successfully, uploaded file name: " + file.getOriginalFilename());
}
return "response";
}

Well great, but you could show what you already have and write exactly what you have a problem with. Can't set the content disposition? Fine, but then you could show what you already have and write exactly what you have a problem with. Can't set the content disposition?
#PostMapping(value = "/", produces = MediaType.APPLICATION_OCTET_STREAM_VALUE)
public ResponseEntity<Resource> handleFileUpload(#RequestParam("file") MultipartFile file) {
return ResponseEntity.ok().header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=dupa.xlsx").body(file.getResource());
}

Instead of returning String (view in this case I assume) you can change your endpoint to return byte array with the file content
public #ResponseBody byte[] uploadFile(
You should also provide configuration to the #PostMapping with the media type of the file if you know what kind it's going to be.
#PostMapping(value = "/uploadFile", produces = MediaType.IMAGE_JPEG_VALUE)
Another solution is to return ResponseEntity. The documentation has two examples for it (https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/http/ResponseEntity.html)

upload to local WebDav - spring boot

I have problem with upload file to local WebDav. So far i have:
public interface IStorageService {
URI SaveFile(String filename, InputStream inputStream);
}
#Component
public class LocalStorageService implements IStorageService {
#Value( "C:\temp" )
private String filestorePath;
public URI SaveFile(String filename, InputStream inputStream) {
var rootLocation = Paths.get(filestorePath);
var filePath = rootLocation.resolve(filename);
try {
Files.copy(inputStream, filePath);
} catch (IOException e) {
throw new RuntimeException("Failure save file to " + filename + " in " + filestorePath + "." + e.getMessage(), e);
}
return filePath.toUri();
}
}
and controller
private final DocumentService documentService;
public DocumentController(DocumentService documentService) {
this.documentService = documentService;
}
#RequestMapping(method = RequestMethod.POST)
public DocumentModel handleFileUpload(#RequestParam("file") MultipartFile file) throws IOException {
return documentService.handleFileUpload(file.getOriginalFilename(), file.getInputStream());
}
And it is works correctly, the file is uploaded to C:/temp...
Now I would like to do the same but upload file to local WebDav. When i change in #Value "C:\temp to "http://localhost" (this is ma webdav location) i have:
invalidpathexception: illegal char <:> at index 4: http://localhost
or when I declare http//localhost without <:>
nosuchfileexception: http\localhost
How can I write my code to upload file directly to WebDav.
Parameters of SaveFile method cannot be changed, I need do it with Name as String and InputStream.
I tried with Sardine but to no avail. Could someone help me, give any tips or maybe suggestion of code ?
Greetings !

You can get the path where your web app/ war/ servlet / controllers are deployed :
ServletContext context = getContext();
String fullPath = context.getRealPath("/WEB-INF/test/foo.txt");
For a Spring project, in controller
'#Autowired
'ServletContext context;
And in controller method :
'String uploadPath = context.getRealPath("") + File.separator + UPLOAD_DIRECTORY;
And the real file name, but what if a user uploads same file twice or 2 users upload file with same name?
Better to put in sub directory with user id/ user name and maybe date time or some other identifier like TXN id + some fixed text like
' String fileName = context.getRealPath("") + File.separator + userId + readlName + "xyz."
extnFromMimeType;
And store the path in data base for this transaction/ user as per your busibess use case.
if mime type is image/PMG then extnFromMimeType will be "png"; if jpeg or jpg then "jpg"
See
File path to resource in our war/WEB-INF folder?
how to get getServletContext() in spring mvc Controller
In Spring MVC, how can I set the mime type header when using #ResponseBody
https://developer.mozilla.org/en-US/docs/Web/HTTP/Basics_of_HTTP/MIME_types/Common_types
If can be many images per user/ transaction can also use createTemp File to get a unique file name
using a UUID also possible ... https://stackoverflow.com/a/1293712/1643558 or a large random number

Java-spingboot how to save text document via REST-API?

I am a beginner programmer, help with the implementation of uploading a text file via rest-api java.
I have already implemented the simplest action - unload a file from the server, here is my code:
#GetMapping(value = "/file/{filename:.+}")
public ResponseEntity<Resource> unloadFile(#PathVariable String filename) {
Resource file = storageService.loadAsResource(filename);
return ResponseEntity.ok().header(HttpHeaders.CONTENT_DISPOSITION,
"attachment; filename=\"" + file.getFilename() + "\"").body(file);
}
I can test the file unload by simply following the link!
I cannot test the upload. I find it difficult to write tests. Please tell me if I got a working code and maybe there is a better way to upload. My code upload:
#PostMapping(value = "/file")
public ResponseEntity<MultipartFile> uploadFile(MultipartFile file) {
storageService.store(file);
return ResponseEntity.ok().body(file);
}
Thank you so much!

To upload the file/files using spring boot application we use same method that we had for servlet containers. In your controller
#PostMapping("/uploadFile")
public ResponseEntity<Object> uploadFile(#RequestParam("file") MultipartFile file) {
String fileName = yourStorageService.storeFile(file);
String = ServletUriComponentsBuilder.fromCurrentContextPath()
.path("/downloadFile/")
.path(fileName)
.toUriString();
//You can even generate download links.
return new ResponseEntity<Object>(HttpStatus.Ok, "Uploaded", fileDownloadUri);
}
To download the files:
#GetMapping("/downloadFile/{fileName}")
public ResponseEntity<Resource> downloadFile(#PathVariable String fileName, HttpServletRequest request) {
// Load file as Resource from DB or local
Resource resource = fileStorageService.loadFileAsResource(fileName);
return ResponseEntity.ok()
.contentType(MediaType.parseMediaType(contentType))
.header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"")
.body(resource);

For #PostMapping(value = "/file") endpoint , its best to return a success/error status instead of returning the file,if file is larger ..it takes time to return back.
Better to return success state. 200 ok.

download file java spring rest api

i want to make a rest api controller (spring boot) that when petitioned with a get will allow me to download an excel file. currently i have this endpoint:
#RequestMapping(value = "/download.xls", method = RequestMethod.GET)
public ResponseEntity Survey_Reports(#RequestParam(value = "evaluated") String evaluated){
return surveyService.getSurveysFile(evaluated);
}
wich ultimately calls to this method:
public static ResponseEntity getDownloadResponse() {
File file2Upload = new File("Survey_Reports.xls");
Path path = Paths.get(file2Upload.getAbsolutePath());
ByteArrayResource resource = null;
try {
resource = new ByteArrayResource(Files.readAllBytes(path));
} catch (IOException e) {
logger.error("there was an error getting the file bytes ", e);
}
return ResponseEntity.ok()
.contentLength(file2Upload.length())
//this line doesnt seem to work as i set the file format in the controller request mapping
.contentType(MediaType.parseMediaType("application/vnd.ms-excel"))
.body(resource);
}
everything seems to work semi-fine as i get the download.xls(as the mapping) file correclty, but now i want to make the downloaded file have some specific name like: evaluatedName.xls or userDateEndDate.xls or some other stuff, is there a way to edit the response entity to do so? so that i dont have to name the mapping "download.xls"

In context of HttpServletResponse response you can do this like this
response.setContentType("application/csv");
response.setHeader("Content-Disposition", "attachment; filename=" + csvName);
and for ResponseEntity i assume you can use something like this:
ResponseEntity.ok().header("Content-Disposition","attachment; filename=" + csvName );

Java servlet cuts off file extension

I'm attempting to serve local or proxy files via my Java application.
With something like this
#ResponseBody
#RequestMapping(value = "/file/{file}", method = RequestMethod.GET)
public void doGet(HttpServletRequest request, HttpServletResponse response,#PathVariable("file") String f) throws IOException {
String filename = URLDecoder.decode(f, "UTF-8");
File file = new File("resources/files/", filename);
response.setHeader("Content-Type", "video/mp4");
response.setHeader("Content-Length", String.valueOf(file.length()));
response.setHeader("Content-Disposition", "inline; filename=\"" + file.getName() + "\"");
Files.copy(file.toPath(), response.getOutputStream());
}
With an example URL such as
example.com/file/out2KP2_1.mp4
I'm getting the error:
Problem accessing /file/out2KP2_1.mp4. Reason:
resources\files\out2KP2_1 Caused by:
java.nio.file.NoSuchFileException: resources\files\out2KP2_1 at
sun.nio.fs.WindowsException.translateToIOException(WindowsException.java:79)
If I add a trailing / to the url and requestMapping, it works, but on iOS and a few other places the video player doesn't seem to like loading a file with a trailing slash so it doesn't suit my purposes.
Any help appriciated.

Thanks for the mark down. Take it you didn't know the answer!?
It's a problem with Spring, you have to add :.+ to the file URL variable
i.e. #RequestMapping(value = "/file/{file:.+}", method = RequestMethod.GET)