I want to preview a pdf file genereted with java, but the following code gives this error

Unrecognized response type; displaying content as text.

@GetMapping("/previewPDF/{codeStudent}")
    public ResponseEntity<byte[]> previewPDF(@PathVariable("codeStudent") String code) throws IOException {
        
        byte[] pdf = //pdf content in bytes

        HttpHeaders headers = new HttpHeaders();      
        headers.add("Content-Disposition", "inline; filename="   "example.pdf");
        headers.setContentType(MediaType.parseMediaType("application/pdf"));
        return ResponseEntity.ok().headers(headers).body(pdf); 
    }

UPDATE: here is a screenshot of the error

CodePudding user response：

You need to specify the response PDF Media Type for your resource.
See RFC standart. Full list of Media Types.
Spring documentation regarding produces Media Type.

    @GetMapping(value = "/previewPDF/{codeStudent}", produces = MediaType.APPLICATION_PDF_VALUE)
    public ResponseEntity<byte[]> previewPDF(@PathVariable("codeStudent") String code) throws IOException

Set also PDF content type for your ResponseEntity

    @GetMapping(value = "/previewPDF/{codeStudent}", produces = MediaType.APPLICATION_PDF_VALUE)
    public ResponseEntity<byte[]> previewPDF(@PathVariable("codeStudent") String code) throws IOException {
        byte[] pdf = null;
        HttpHeaders headers = new HttpHeaders();
        String fileName = "example.pdf";
        headers.setContentDispositionFormData(fileName, fileName);        
        headers.setContentType(MediaType.APPLICATION_PDF);
        return ResponseEntity.ok().headers(headers).body(pdf);
    }