是否有可能在HttpAsynClient中从HttpClient-5.x中止http请求[GET，POST等]？

在HttpAsyncClient中，可以通过设置一个标志位来中止HTTP请求。具体步骤如下：

创建一个自定义的HttpClientBuilder对象，并覆写其createHttpAsyncClient方法。在该方法中，创建一个CloseableHttpAsyncClient实例，并覆写其execute方法。
在execute方法中，将传入的HttpUriRequest对象封装成一个AbortableHttpRequest对象，然后调用execute方法执行请求。
在AbortableHttpRequest对象的execute方法中，判断一个标志位（例如isAborted），如果标志位为true，则直接返回空结果；否则，调用父类的execute方法执行请求。
当需要中止请求时，将标志位设置为true。

以下是一个示例代码：

import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
import org.apache.http.impl.nio.client.HttpAsyncClients;
import org.apache.http.nio.client.methods.AbortableHttpRequest;
import org.apache.http.nio.protocol.BasicAsyncResponseConsumer;
import org.apache.http.nio.protocol.HttpAsyncRequestProducer;
import org.apache.http.protocol.HttpContext;

public class CustomHttpAsyncClient {

    public CloseableHttpAsyncClient createHttpAsyncClient() {
        return HttpAsyncClients.custom()
                .setHttpAsyncRequester(new CustomHttpAsyncRequester())
                .build();
    }

    private class CustomHttpAsyncRequester extends DefaultHttpAsyncRequester {

        @Override
        public <T> Future<T> execute(
                final HttpAsyncRequestProducer requestProducer,
                final HttpAsyncResponseConsumer<T> responseConsumer,
                final HttpContext context,
                final FutureCallback<T> callback) {

            return super.execute(
                    new AbortableHttpRequestProducer(requestProducer),
                    responseConsumer,
                    context,
                    callback);
        }
    }

    private class AbortableHttpRequestProducer implements HttpAsyncRequestProducer {

        private final HttpAsyncRequestProducer requestProducer;
        private volatile boolean isAborted = false;

        public AbortableHttpRequestProducer(HttpAsyncRequestProducer requestProducer) {
            this.requestProducer = requestProducer;
        }

        @Override
        public HttpUriRequest generateRequest() throws IOException, HttpException {
            return requestProducer.generateRequest();
        }

        @Override
        public void produceContent(ContentEncoder encoder, IOControl ioControl) throws IOException {
            requestProducer.produceContent(encoder, ioControl);
        }

        @Override
        public void requestCompleted(HttpContext context) {
            requestProducer.requestCompleted(context);
        }

        @Override
        public boolean isRepeatable() {
            return requestProducer.isRepeatable();
        }

        @Override
        public void resetRequest() throws IOException {
            requestProducer.resetRequest();
        }

        @Override
        public void close() throws IOException {
            requestProducer.close();
        }

        @Override
        public void failed(Exception ex) {
            requestProducer.failed(ex);
        }

        @Override
        public void close(CloseMode closeMode) {
            isAborted = true;
            requestProducer.close(closeMode);
        }
    }
}

使用示例：

CloseableHttpAsyncClient httpclient = new CustomHttpAsyncClient().createHttpAsyncClient();
httpclient.start();

HttpUriRequest request = new HttpGet("http://www.example.com");

Future<HttpResponse> future = httpclient.execute(request, new BasicAsyncResponseConsumer(), null);

// 在需要中止请求时
((AbortableHttpRequest) request).abort();

HttpResponse response = future.get();

这样，当调用((AbortableHttpRequest) request).abort()时，就可以中止HTTP请求。