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咱们晓得每个音讯的解决工夫是不同的，换句话说音讯的复杂度是不同的，有些音讯很简单，须要很久的工夫，有些音讯很简略，只需耗时一会就能够实现，而在理论状况下如何分配资源，让效率达到最大化，从而实现按能力分配任务，达到物尽其用。这就须要音讯的散发机制。
一、Fair dispatch(偏心散发)
这里咱们创立 DistributionSender.java 和 DistributionReceiver.java 来模仿发送者和接收者。
DistributionSender.java
@Component
public class DistributionSender {
@Autowired
private AmqpTemplate rabbitTemplate;
public void send(int i) {
// 发送的音讯
String message = "This is a task, and the complexity is" + i + "。" + StringUtils.repeat(".", i);
this.rabbitTemplate.convertAndSend("distribu", message);
}
}应用默认交换机，队列为“distribu”
/**
* 申明 distribu 队列
*
* @return
*/
@Bean
public Queue DistribuQueue() {return new Queue("distribu");
}java 和 DistributionReceiver.java
@Component
public class DistributionReceiver {
/**
* 消费者 A
*
* @param msg
*/
@SuppressWarnings("deprecation")
@RabbitListener(queues = "distribu")
public void processA(Message message) {String msg = new String(message.getBody());
System.out.println("DistributionReceiverA :" + msg);
SimpleDateFormat time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSSS");
System.out.println("ProccessingA... at" + time.format(new Date()));
try {for (char ch : msg.toCharArray()) {if (ch == '.') {doWork(1000);
}
}
} catch (InterruptedException e) { } finally {System.out.println("A Done! at" + time.format(new Date()));
}
}
private void doWork(long time) throws InterruptedException {Thread.sleep(time);
}
}增加 RabbitTest.java 文件模仿申请
@Controller
public class RabbitTest{
@Autowired
private DistributionSender distributionSender;
/**
* 散发机制音讯发送测试
*/
@GetMapping("/distribu")
public void distribu() {distributionSender.send(3);
}
}运行程序，拜访 http://localhost:8080/rabbit/…，能够失去上面的打印的信息：
DistributionReceiverA : This is a task, and the complexity is 3。...
ProccessingA... at 2018-05-23 21:29:18:0628
A Done! at 2018-05-23 21:29:21:0639从打印的信息能够看出这里就模仿了实现工作须要 3 秒钟的工夫工作实现。
上面咱们更改发送的音讯数量，在 controller 控制器外面进行更改，如下：
/**
* 散发机制音讯发送测试
*/
@GetMapping("/distribu")
public void distribu() {for (int i = 0; i < 5; i++) {
// 发送工作复杂度都为 1 的音讯
distributionSender.send(1);
}
}模仿发送 5 条音讯，并且每条发送的音讯的复杂度都是雷同的，复杂度都为 1。
而后再在 receiver 包中 DistributionReceiver.java 新增一个消费者 B，如下：
/**
* 消费者 B
*
* @param msg
*/
@SuppressWarnings("deprecation")
@RabbitListener(queues = "distribu")
public void processB(Message message) {String msg = new String(message.getBody());
System.out.println("DistributionReceiverB :" + msg);
SimpleDateFormat time = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss:SSSS");
System.out.println("ProccessingB... at" + time.format(new Date()));
try {for (char ch : msg.toCharArray()) {if (ch == '.') {doWork(1000);
}
}
} catch (InterruptedException e) { } finally {System.out.println("B Done! at" + time.format(new Date()));
}
}再次运行程序，拜访接口，后果如下：
DistributionReceiverA : This is a task, and the complexity is 1。.
ProccessingA... at 2018-05-22 23:23:43:0014
DistributionReceiverB : This is a task, and the complexity is 1。.
ProccessingB... at 2018-05-22 23:23:43:0014
A Done! at 2018-05-22 23:23:44:0017
B Done! at 2018-05-22 23:23:44:0017
DistributionReceiverA : This is a task, and the complexity is 1。.
DistributionReceiverB : This is a task, and the complexity is 1。.
ProccessingA... at 2018-05-22 23:23:44:0093
ProccessingB... at 2018-05-22 23:23:44:0093
A Done! at 2018-05-22 23:23:45:0095
B Done! at 2018-05-22 23:23:45:0095
DistributionReceiverB : This is a task, and the complexity is 1。.
ProccessingB... at 2018-05-22 23:23:45:0143
B Done! at 2018-05-22 23:23:46:0148在音讯雷同，A、B 解决能力一样状况下，咱们能够发现 A、B 简直是同时解决音讯，音讯发送程序为 A ->B->A->B->B。能够看出这里并没有实现 A 与 B 均匀轮询的状况，在最初的状况 B 执行了两次。
接着当初咱们把 A 解决能力更改为每个点要 Thread.sleep(4000）, B 为 Thread.sleep(1000），就是 B 的解决能力是 A 的四倍。运行一下，咱们看一下打印的后果：
DistributionReceiverB : This is a task, and the complexity is 1。.
ProccessingB... at 2018-05-22 23:24:48:0623
DistributionReceiverA : This is a task, and the complexity is 1。.
ProccessingA... at 2018-05-22 23:24:48:0623
B Done! at 2018-05-22 23:24:49:0624
DistributionReceiverB : This is a task, and the complexity is 1。.
ProccessingB... at 2018-05-22 23:24:49:0663
B Done! at 2018-05-22 23:24:50:0664
DistributionReceiverB : This is a task, and the complexity is 1。.
ProccessingB... at 2018-05-22 23:24:50:0704
B Done! at 2018-05-22 23:24:51:0709
DistributionReceiverB : This is a task, and the complexity is 1。.
ProccessingB... at 2018-05-22 23:24:51:0748
A Done! at 2018-05-22 23:24:52:0629
B Done! at 2018-05-22 23:24:52:0749 当初咱们能够清晰地看到在这里 B 解决了 4 条音讯，而 A 只解决了 1 条音讯。这里就是按偏心散发的机制来发送音讯的，即按消费者解决能力来散发音讯。
这就是偏心散发。
二、Round-robin dispatch(轮询散发)
相较于偏心散发而言，轮询散发即不去判断消费者的解决速率，也不思考每个工作的时长，依照轮流排序的形式，把工作一一发给消费者，并且是提前一次性调配，并非一个一个调配。
