异步性在Vertx，它被设置

Question

之前在我MainVerticle我设置路由器

router.get("/persons").handler(ctx -> apiService.getPersons(ctx, client)); 

我要调用两次相同的主机列表返回空，首先我需要的人ID的列表，然后调用同一个主机的另一种方法来获取人员详细信息。 。所以，在这段代码中，我正在另一个接听电话。由于异步性，personList是空的，因为Vertx不等待第二个呼叫的回复，第二个呼叫的回复稍后出现，但是当然personList是空的。在我的测试案例中，迭代器有两个元素。我应该如何实现它以确保列表将被正确返回？

 public void getPersons(RoutingContext routingContext, WebClient client){ 
    logger.info("getpersons"); 
    routingContext.response().headers().add("content-type", "application/json"); 
    String wshost= ConfigUtils.getStringConfig(vertx,"personws.url"); 
    String url = wshost+"/persons"; 
    client.getAbs(url).send(response -> { 
     try { 
      if (response.succeeded() && response.result().statusCode()==200) { 
       List<Person> personList = new ArrayList<Person>(); 
       logger.info("Server content " + response.result().bodyAsString()); 

       Iterator<Object> iterator = response.result().bodyAsJsonArray().iterator(); 
       while(iterator.hasNext()){ 
        Object obj = iterator.next(); 
        JsonObject jsonPerson = (JsonObject) obj ; 
        logger.debug("personId: {}", jsonPerson.getString("id")); 
        Person person = new Person(); 
        person.setId(jsonPerson.getString("id")); 

        String url2 = wshost+"/persons/"+jsonPerson.getString("id"); 
        logger.info("Calling ws to get person details for : {}", jsonPerson.getString("id"), url2); 
        client.getAbs(url2).send(response2 -> { 
         if (response2.succeeded() && response2.result().statusCode()==200) { 

          JsonObject jsonDetails = response2.result().bodyAsJsonObject(); 
          person.setDetail(jsonDetails); 
          personList.add(person); 
          logger.info("person is {} ", person); 
          logger.info("iterator.hasNext():{}", iterator.hasNext()); 


         } 
         else{ 
          routingContext.response().setStatusCode(500); 
          routingContext.response().end(buildError("Failed to get json ", 600).encode()); 
         } 

        }); 

       }; 
       logger.info("personList: {} ", personList); 
       logger.info("personList size {} ", personList.size()); 
       routingContext.response().setStatusCode(200).end(new JsonArray(personList).toString()); 
      } else { 
       logger.error("Cannot get persons"); 
       routingContext.response().setStatusCode(500); 
       routingContext.response().end(buildError("Failed to get persons", 100).encode()); 
      } 
     } catch (Exception e) { 
      e.printStackTrace(); 
      routingContext.response().setStatusCode(500); 
      routingContext.response().end(buildError("Exception in API- Failed to get get persons for fleet "+routingContext.request().headers().get("fleet"), 300).encode()); 
     } 

    }); 

} 

Answer 1

首先，你不要只打电话给你的主机两次。您在初始请求中按每个人数调用n + 1次。

最简单的方式来实现你需要的是算你希望得到的人数：

   int expected = response.result().bodyAsJsonArray().size(); 

       Iterator<Object> iterator = response.result().bodyAsJsonArray().iterator(); 
       while(iterator.hasNext()){ 
        Object obj = iterator.next(); 
        JsonObject jsonPerson = (JsonObject) obj ; 
        logger.debug("personId: {}", jsonPerson.getString("id")); 
        Person person = new Person(); 
        person.setId(jsonPerson.getString("id")); 

        String url2 = wshost+"/persons/"+jsonPerson.getString("id"); 
        logger.info("Calling ws to get person details for : {}", jsonPerson.getString("id"), url2); 
        client.getAbs(url2).send(response2 -> { 
         if (response2.succeeded() && response2.result().statusCode()==200) { 

          JsonObject jsonDetails = response2.result().bodyAsJsonObject(); 
          person.setDetail(jsonDetails); 
          personList.add(person); 
          logger.info("person is {} ", person); 
          logger.info("iterator.hasNext():{}", iterator.hasNext()); 

          // That's the last one 
          if (personList.size() == expected) { 
           // Only now complete the request 
           routingContext.response().setStatusCode(200).end(new JsonArray(personList).toString()); 
          } 
         } 
         else{ 
          routingContext.response().setStatusCode(500); 
          routingContext.response().end(buildError("Failed to get json ", 600).encode()); 
         } 

        }); 

       }; 
       logger.info("personList: {} ", personList); 
       logger.info("personList size {} ", personList.size()); 
       // Moved inside callback 

其他的方式是使用CompositeFuture： http://vertx.io/docs/vertx-core/groovy/#_concurrent_composition