Apache camel Apache Camel concurrentConsumers与线程

我花了将近两天的时间来理解ApacheCamel中concurrentConsumers与threads的概念。但我真的不明白这个概念。有人能帮我理解这个概念吗。我正在使用camel 2.12.0

   from("jms:queue:start?concurrentConsumers=5")
   .threads(3, 3, "replyThread")
   .bean(new SomeBean());

   pom.xml
   ==========================================  
   <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <camel.version>2.12.0</camel.version>
</properties>

<dependencies>
    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.8.1</version>
        <scope>test</scope>
    </dependency>

    <!-- required by both client and server -->
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-core</artifactId>
        <version>${camel.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-spring</artifactId>
        <version>${camel.version}</version>
    </dependency>
    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-jms</artifactId>
        <version>${camel.version}</version>
    </dependency>

    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-test</artifactId>
        <version>${camel.version}</version>
    </dependency>

    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-activemq</artifactId>
        <version>1.1.0</version>
    </dependency>

    <dependency>
        <groupId>org.apache.camel</groupId>
        <artifactId>camel-test-spring</artifactId>
        <version>2.12.1</version>
    </dependency>
</dependencies>


   //posting to queue
   for (int i = 0; i < 10; i++) {
      System.out.println(Thread.currentThread() + " sending request..." + i);
      template.asyncCallbackRequestBody("jms:queue:start", (body + " " + i), callback);
   } 

   //my call back
   public class MyCallback extends SynchronizationAdapter {

   @Override
   public void onComplete(Exchange exchange) {
      String body = exchange.getOut().getBody(String.class);
      System.out.println(Thread.currentThread() + " Callback Resposne..." +body);
 }
}

  public static class SomeBean {
    public void someMethod(Exchange body) {
        System.out.println(Thread.currentThread() + " Received: " + body.getIn().getBody());
        body.getOut().setBody(body.getIn().getBody());
    }
}

---

如果要检查JMS线程池，则需要像下面这样更改路由

from("jms:queue:start?concurrentConsumers=5")
   .bean(new SomeBean())
   .threads(3, 3, "replyThread")
   .bean(new SomeBean());

---

SomeBean可以向您展示驼峰路由中使用了不同的线程池。

JMS组件具有内置的线程池，它可以根据向上查询的消息数量进行很好的上下扩展

所以就用这个吧

 from("jms:queue:start?concurrentConsumers=5")
   .bean(new SomeBean());

您还可以指定一个最大值，以便有一个范围

 from("jms:queue:start?concurrentConsumers=5&maxConcurrentConsumers=10")
   .bean(new SomeBean());

---

你真的不需要第二个线程池，只要使用JMS中的线程池就可以了。啊，再往下看一点。它说从Camel 2.10.3开始，您不再需要threads（）。感谢您的快速回复。当我在@Section“Request-reply over JMS”中读到这篇文档时，我感到困惑。线程（5）需要定义我们是否要处理异步回复。应该提到的是，如果使用者最终应该缩小规模，那么还必须使用“maxMessagesPerTask”参数。

 from("jms:queue:start?concurrentConsumers=5&maxConcurrentConsumers=10")
   .bean(new SomeBean());