java - Spring 集成在方法之间传递多个参数

Question

我正在使用 Spring Integration 来执行一些 http 请求，然后解析它并最终将其保存到数据库
我想在转换方法中访问 App 对象，正如您所看到的 App 对象是 download 方法的参数(从另一个 channel )，解决方案是什么？
这是我的代码:

@ServiceActivator(inputChannel = "channel1", outputChannel = "channel2")
public ResponseEntity<DetailsItemParser[]> download(App app)
{
    String url = config.getAppDetailUrl();
    try
    {
        SSLUtil.turnOffSslChecking();
    }
    catch (Exception e)
    {
        LOG.error(e.getMessage());
    }
    HttpHeaders requestHeaders = new HttpHeaders();
    requestHeaders.setAccept(Collections.singletonList(new MediaType("application","json")));
    HttpEntity<?> requestEntity = new HttpEntity<Object>(requestHeaders);
    detailsCrawlerRestTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
    ResponseEntity<DetailsItemParser[]> responseEntity = detailsCrawlerRestTemplate.exchange(url, HttpMethod.GET, requestEntity, DetailsItemParser[].class, app.getExternalId());

    return responseEntity;

}

@Splitter(inputChannel = "channel2", outputChannel = "channel3")
public List<DetailsItemParser> scrape(ResponseEntity<DetailsItemParser[]> payload)
{
    return new ArrayList<>(Arrays.asList(payload.getBody()));
}



@Filter(inputChannel = "channel3", outputChannel = "channel4")
public boolean filter(DetailsItemParser detailsItemParser)
{
    final Set<ConstraintViolation<DetailsItemParser>> violations = validator.validate(detailsItemParser);
    if (violations != null && !violations.isEmpty())
    {
        return false;
    }

    return true;
}

@Transformer(inputChannel = "channel4", outputChannel = "channel5")
public App convert(DetailsItemParser payload)
{

    App app = appRepository.findById(payload.getId());

    LOG.info("entry={}", o.toString());
    return null;
}

Answer 1

如果您与 payload 完全匹配，则可以使用多个参数，其余所有内容都必须通过 @Header 配置。你不能有两个payload ，并且 Java 方法不能有两个返回值。

所以，如果您想携带 App对象与 ResponseEntity<DetailsItemParser[]> 并排考虑将其添加到 headers .

您可以使用HeaderEnricher在发送至 channel1 之前或返回整个Message<?>来自download()方法并添加App使用 MessageBuilder 到标题.

convert()方法则可以指定为:

public App convert(DetailsItemParser payload, @Header("app") App app)

更新

HeaderEnricher通过 Java 配置的示例:

    @Bean
    @Transformer(inputChannel = "routingSlipHeaderChannel", outputChannel = "processChannel")
    public HeaderEnricher headerEnricher() {
        return new HeaderEnricher(Collections.singletonMap(IntegrationMessageHeaderAccessor.ROUTING_SLIP,
                new RoutingSlipHeaderValueMessageProcessor(routeStrategy())));
    }

引用手册中的更多信息:https://docs.spring.io/spring-integration/reference/html/messaging-transformation-chapter.html#_configuring_a_header_enricher_with_java_configuration