download a file from Spring boot rest service

Question

I am trying to download a file from a Spring boot rest service.

@RequestMapping(path="/downloadFile",method=RequestMethod.GET)     @Consumes(MediaType.APPLICATION_JSON_VALUE)     public  ResponseEntity<InputStreamReader> downloadDocument(                 String acquistionId,                 String fileType,                 Integer expressVfId) throws IOException {         File file2Upload = new File("C:\\Users\\admin\\Desktop\\bkp\\1.rtf");         HttpHeaders headers = new HttpHeaders();         headers.add("Cache-Control", "no-cache, no-store, must-revalidate");         headers.add("Pragma", "no-cache");         headers.add("Expires", "0");         InputStreamReader i = new InputStreamReader(new FileInputStream(file2Upload));         System.out.println("The length of the file is : "+file2Upload.length());          return ResponseEntity.ok().headers(headers).contentLength(file2Upload.length())                 .contentType(MediaType.parseMediaType("application/octet-stream"))                 .body(i);         } 

When I tried to download the file from the browser, it starts the download, but always fails. Is there anything wrong with the service which is causing the download to fail?

Answer 1

Option 1 using an InputStreamResource

Resource implementation for a given InputStream.

Should only be used if no other specific Resource implementation is > applicable. In particular, prefer ByteArrayResource or any of the file-based Resource implementations where possible.

@RequestMapping(path = "/download", method = RequestMethod.GET) public ResponseEntity<Resource> download(String param) throws IOException {      // ...      InputStreamResource resource = new InputStreamResource(new FileInputStream(file));      return ResponseEntity.ok()             .headers(headers)             .contentLength(file.length())             .contentType(MediaType.APPLICATION_OCTET_STREAM)             .body(resource); } 

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Option2 as the documentation of the InputStreamResource suggests - using a ByteArrayResource:

@RequestMapping(path = "/download", method = RequestMethod.GET) public ResponseEntity<Resource> download(String param) throws IOException {      // ...      Path path = Paths.get(file.getAbsolutePath());     ByteArrayResource resource = new ByteArrayResource(Files.readAllBytes(path));      return ResponseEntity.ok()             .headers(headers)             .contentLength(file.length())             .contentType(MediaType.APPLICATION_OCTET_STREAM)             .body(resource); } 

Answer 2

The below Sample code worked for me and might help someone.

import org.springframework.core.io.ByteArrayResource; 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.RequestMapping; import org.springframework.web.bind.annotation.RequestMethod; import org.springframework.web.bind.annotation.RequestParam; import org.springframework.web.bind.annotation.RestController;  import java.io.File; import java.io.IOException; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths;  @RestController @RequestMapping("/app") public class ImageResource {      private static final String EXTENSION = ".jpg";     private static final String SERVER_LOCATION = "/server/images";      @RequestMapping(path = "/download", method = RequestMethod.GET)     public ResponseEntity<Resource> download(@RequestParam("image") String image) throws IOException {         File file = new File(SERVER_LOCATION + File.separator + image + EXTENSION);          HttpHeaders header = new HttpHeaders();         header.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=img.jpg");         header.add("Cache-Control", "no-cache, no-store, must-revalidate");         header.add("Pragma", "no-cache");         header.add("Expires", "0");          Path path = Paths.get(file.getAbsolutePath());         ByteArrayResource resource = new ByteArrayResource(Files.readAllBytes(path));          return ResponseEntity.ok()                 .headers(header)                 .contentLength(file.length())                 .contentType(MediaType.parseMediaType("application/octet-stream"))                 .body(resource);     }  }