我有一个使用Vertx框架和Kafka的Java应用程序。
有以下类可以实现Kafka使用者和Web服务：

package com.example.starter;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import io.vertx.core.*;
import io.vertx.kafka.client.consumer.KafkaConsumer;

public class ConsumerVerticle extends AbstractVerticle {
    
    public void initKafkaConsumer() {
        Map<String, String> config = new HashMap<>();
        config.put("bootstrap.servers", "localhost:9092");
        config.put("key.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        config.put("value.deserializer", "org.apache.kafka.common.serialization.StringDeserializer");
        config.put("group.id", "my_group");
        config.put("auto.offset.reset", "latest");
        config.put("enable.auto.commit", "true");
    
        KafkaConsumer<String, String> consumer = KafkaConsumer.create(vertx, config);
    
        consumer.handler(record -> {
          System.out.println("Processing key=" + record.key() + ",value=" + record.value() +
            ",partition=" + record.partition() + ",offset=" + record.offset());
          try {TimeUnit.SECONDS.sleep(1);}
          catch(Exception e){}
        });
        consumer.subscribe("quickstart");
      }

      @Override
      public void start() throws Exception {
          System.out.println("CONSUMER THREAD: Thread name -> " + Thread.currentThread().getName());
          initKafkaConsumer();
      }
}

package com.example.starter;
import io.vertx.core.AbstractVerticle;
import io.vertx.ext.web.Router;

public class WebServiceVerticle extends AbstractVerticle {

    private void initWebService() {
        Router router = Router.router(vertx);
        router.get("/healthcheck").handler(rc -> rc.response().end("OK"));
        vertx.createHttpServer().requestHandler(router)
            .listen(5555, result -> {
            System.out.println("HTTP server started");
        });
    }
    
    @Override
    public void start() throws Exception {
        System.out.println("WEB SERVICE: Thread name -> " + Thread.currentThread().getName());
        initWebService();
    }
}

如果主类定义如下：

package com.example.starter;
import java.util.HashMap;
import java.util.Map;
import io.vertx.core.AbstractVerticle;
import io.vertx.core.DeploymentOptions;
import io.vertx.core.Vertx;

public class MainVerticle extends AbstractVerticle {
  
  @Override
  public void start() throws Exception {

    System.out.println("MAIN THREAD: Thread name -> " + Thread.currentThread().getName());    
    DeploymentOptions options = new DeploymentOptions();
    vertx.deployVerticle(WebServiceVerticle.class, options);
    vertx.deployVerticle(ConsumerVerticle.class, options);
}

输出如下所示：

MAIN THREAD: Thread name -> vert.x-eventloop-thread-1
WEB SERVICE: Thread name -> vert.x-eventloop-thread-2
CONSUMER THREAD: Thread name -> vert.x-eventloop-thread-3

这对我来说很有意义，因为每个垂直线都被分配给一个特定的线程。
另一方面，我不理解以下情况：

public class MainVerticle extends AbstractVerticle {
  
  @Override
  public void start() throws Exception {

    System.out.println("MAIN THREAD: Thread name -> " + Thread.currentThread().getName());    
    DeploymentOptions options = new DeploymentOptions();
    vertx = Vertx.vertx(new VertxOptions().setMaxEventLoopExecuteTime(1)); // The vertx object is explicitly initialized
    vertx.deployVerticle(WebServiceVerticle.class, options);
    vertx.deployVerticle(ConsumerVerticle.class, options);
}

在这种情况下，输出如下：

MAIN THREAD: Thread name -> vert.x-eventloop-thread-1
WEB SERVICE: Thread name -> vert.x-eventloop-thread-0
CONSUMER THREAD: Thread name -> vert.x-eventloop-thread-1

我希望在这个实现中不同的顶点也有不同的线程。有人能解释这个行为吗？