Spring REST文件下载无法设置头部内容类型附件

import org.springframework.core.io.InputStreamResource;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;

@RestController
public class FileDownloadController {

    @GetMapping("/download")
    public ResponseEntity<InputStreamResource> downloadFile() throws IOException {
        File file = new File("path/to/file.pdf");
        HttpHeaders headers = new HttpHeaders();
        headers.add(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=file.pdf");
        headers.setContentType(MediaType.APPLICATION_PDF);

        InputStreamResource resource = new InputStreamResource(new FileInputStream(file));

        return ResponseEntity.ok()
                .headers(headers)
                .body(resource);
    }
}