返回InputStream SpringMVC

Question

在这种情况下，有什么可能是一个可能的解决方案？我可以在返回InputStreamResource后以某种方式关闭CloseableHttpresponse吗？我确实需要使用

ClosableHttpClient

，该方法应返回一些

Stream。

    public ResponseEntity<InputStreamResource> getFileAsStream(@PathVariable("uuid") String uuid) throws IOException, InterruptedException {
        CloseableHttpResponse response = fileService.importFileByUuid(uuid);
        try {
            HttpEntity entity = response.getEntity();
            HttpHeaders responseHeaders = new HttpHeaders();
            responseHeaders.add(HttpHeaders.CONTENT_LENGTH, String.valueOf(entity.getContentLength()));
            responseHeaders.add(HttpHeaders.CONTENT_TYPE, entity.getContentType().getValue());
            responseHeaders.add(HttpHeaders.CONTENT_DISPOSITION, response.getFirstHeader(HttpHeaders.CONTENT_DISPOSITION).getValue());

            if (entity != null) {
                InputStream inputStream = entity.getContent();
                InputStreamResource inputStreamResource = new InputStreamResource(inputStream);
                return ResponseEntity.ok()
                            .headers(responseHeaders)
                            .body(inputStreamResource);
            }
            throw new IllegalStateException(String.format(
                    "Error during stream downloading, uuid = %s", uuid));
        } finally {
            response.close();
        }
    } 

您始终可以创建从httpentity获得的输入流的副本，并使用副本创建响应率中返回的InputStreamResource。这样，可以在返回响应率之前安全地关闭从HTTPENTITY获得的原始输入流。

InputStream inputStream = entity.getContent();
ByteArrayOutputStream outputStream = new ByteArrayOutputStream();
IOUtils.copy(inputStream, outputStream);
byte[] contentBytes = outputStream.toByteArray();
ByteArrayInputStream byteArrayInputStream = new ByteArrayInputStream(contentBytes);
InputStreamResource inputStreamResource = new InputStreamResource(byteArrayInputStream);

或保存使用字节[]并使用它来返回

ByteArrayResource

而不是

InputStreamResource

Answer 1

使用Servlet API中的HTTP拖车标头的供应商来运行

.close()

侧效应。 filecontroller.java

    @GetMapping(path = "/document")
    public ResponseEntity<?> getSingleDocument(
            @RequestParam(name = "docPath") String documentPath,
            HttpServletResponse response
    ) {
        return fileService.fetchPDF(documentPath, response);
    }

FileService.java

Answer 2