Speicherarme Übertragung großer Dateien via StreamingResponseBody

@RestController
@RequestMapping("/export")
public class DataExportController {
 
    private final LargeDatasetService datasetService;
 
    public DataExportController(LargeDatasetService datasetService) {
        this.datasetService = datasetService;
    }
 
    @GetMapping("/records")
    public ResponseEntity<StreamingResponseBody> streamExport() {
        StreamingResponseBody stream = outputStream -> {
            try (BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(outputStream))) {
                datasetService.streamRecords(record -> {
                    writer.write(record.toCsvLine());
                    writer.newLine();
                });
                writer.flush();
            }
        };
 
        return ResponseEntity.ok()
            .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=export.csv")
            .contentType(MediaType.TEXT_PLAIN)
            .body(stream);
    }
}