Spring Boot Controller export an Excel

Question

I have a java/spring boot application where I want to build an API endpoint that creates and returns a downloadable excel file. Here is my controller endpoint:

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Answer 1

Since you are using ByteArrayResource, you can use the below controller code assuming that the FooService is autowired in the controller class.

@RequestMapping(path = "/download_excel", method = RequestMethod.GET)
public ResponseEntity download(String fileName) throws IOException {

ByteArrayResource resource = fooService.export(fileName);

return ResponseEntity.ok()
        .headers(headers) // add headers if any
        .contentLength(resource.contentLength())
        .contentType(MediaType.parseMediaType("application/vnd.ms-excel"))
        .body(resource);
}