在风暴中使用Apache的AsyncHttpClient

Question

我有一个螺栓，它为每个元组进行API调用（HTTP Get）。 为避免需要等待响应，我一直在寻找使用apache HttpAsyncClient的方法。

在螺栓的prepare方法中实例化客户端之后，execute方法从元组构造URL并调用sendAsyncGetRequest（url）：

private void sendAsyncGetRequest(String url){

    httpclient.execute(new HttpGet(url), new FutureCallback<HttpResponse>() {

        @Override
        public void completed(HttpResponse response) {
            LOG.info("Response Code : " + response.getStatusLine());
            LOG.debug(response.toString());
        }

        @Override
        public void failed(Exception ex) {
            LOG.warn("Async http request failed!", ex);
        }

        @Override
        public void cancelled() {
            LOG.warn("Async http request canceled!");
        }
    });
}

拓扑已部署，但Storm UI显示错误：

java.lang.RuntimeException: java.lang.IllegalStateException: Request cannot be executed; I/O reactor status: STOPPED at backtype.storm.utils.DisruptorQueue.consumeBatchToCursor(DisruptorQueue.java:12

Answer 1

我没有任何问题。 要注意的关键事项是：

1. 在螺栓类作用域上声明客户

    public class MyRichBolt extends BaseRichBolt { private CloseableHttpAsyncClient httpclient; 

2. 实例化并统计客户的螺栓准备方法

    @Override public final void prepare(Map stormConf, TopologyContext context, OutputCollector collector) { try { // start the http client httpclient = HttpAsyncClients.createDefault(); httpclient.start(); // other initialization code ... } catch (Throwable exception) { // handle errors } } 

3. 在螺栓的execute方法中进行调用

    @Override public final void execute(Tuple tuple) { // format the request url String url = ... sendAsyncGetRequest(url); } private void sendAsyncGetRequest(String url){ logger.debug("Async call to URL..."); HttpGet request = new HttpGet(url); HttpAsyncRequestProducer producer = HttpAsyncMethods.create(request); AsyncCharConsumer<HttpResponse> consumer = new AsyncCharConsumer<HttpResponse>() { HttpResponse response; @Override protected void onResponseReceived(final HttpResponse response) { this.response = response; } @Override protected void onCharReceived(final CharBuffer buf, final IOControl ioctrl) throws IOException { // Do something useful } @Override protected void releaseResources() { } @Override protected HttpResponse buildResult(final HttpContext context) { return this.response; } }; httpclient.execute(producer, consumer, new FutureCallback<HttpResponse>() { @Override public void completed(HttpResponse response) { // do something useful with the response logger.debug(response.toString()); } @Override public void failed(Exception ex) { logger.warn("!!! Async http request failed!", ex); } @Override public void cancelled() { logger.warn("Async http request canceled!"); } }); } 

Answer 2

您是否在执行回调之前在主流程中关闭了客户端（client.close（）;）？

该错误表明IO路径已关闭。 通常，异步客户端的实例应重新用于重复的请求，并且仅在发出“ ALL”请求时（例如，在应用程序关闭时）才将其销毁。