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本文主要展示一下open-messaging使用实例
consumer
PullConsumer
openmessaging-java/openmessaging-api-samples/src/main/java/io/openmessaging/samples/consumer/PullConsumerApp.java
public class PullConsumerApp {
public static void main(String[] args) throws OMSResourceNotExistException {
//Load and start the vendor implementation from a specific OMS driver URL.
final MessagingAccessPoint messagingAccessPoint =
OMS.getMessagingAccessPoint("oms:rocketmq://[email protected]/us-east");
messagingAccessPoint.startup();
//Fetch a ResourceManager to create Queue resource.
ResourceManager resourceManager = messagingAccessPoint.resourceManager();
resourceManager.createQueue( "NS://HELLO_QUEUE", OMS.newKeyValue());
//Start a PullConsumer to receive messages from the specific queue.
final PullConsumer pullConsumer = messagingAccessPoint.createPullConsumer();
pullConsumer.attachQueue("NS://HELLO_QUEUE");
pullConsumer.startup();
//Register a shutdown hook to close the opened endpoints.
Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
@Override
public void run() {
pullConsumer.shutdown();
messagingAccessPoint.shutdown();
}
}));
//Receive one message from queue.
Message message = pullConsumer.receive();
//Acknowledge the consumed message
pullConsumer.ack(message.sysHeaders().getString(Message.BuiltinKeys.RECEIPT_HANDLE));
}
}
- 首先创建messagingAccessPoint，然后启动是调用start，在shutdownHook里头调用shutdown
- 然后通过resourceManager创建queue，和pullConsumer，并将其绑定
- 之后调用pullConsumer的startup方法启动，然后关闭时shutdown方法
- pullConsumer调用receive方法来拉取消息，这里改名为pull方法可能更合适些
- pullConsumer可以对消息进行ack
PushConsumer
openmessaging-java/openmessaging-api-samples/src/main/java/io/openmessaging/samples/consumer/PushConsumerApp.java
public class PushConsumerApp {
public static void main(String[] args) throws OMSResourceNotExistException {
//Load and start the vendor implementation from a specific OMS driver URL.
final MessagingAccessPoint messagingAccessPoint =
OMS.getMessagingAccessPoint("oms:rocketmq://localhost:10911/us-east");
messagingAccessPoint.startup();
//Fetch a ResourceManager to create Queue resource.
ResourceManager resourceManager = messagingAccessPoint.resourceManager();
final PushConsumer consumer = messagingAccessPoint.createPushConsumer();
consumer.startup();
//Register a shutdown hook to close the opened endpoints.
Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
@Override
public void run() {
consumer.shutdown();
messagingAccessPoint.shutdown();
}
}));
//Consume messages from a simple queue.
String simpleQueue = "NS://HELLO_QUEUE";
resourceManager.createQueue( simpleQueue, OMS.newKeyValue());
//This queue doesn't has a source queue, so only the message delivered to the queue directly can
//be consumed by this consumer.
consumer.attachQueue(simpleQueue, new MessageListener() {
@Override
public void onReceived(Message message, Context context) {
System.out.println("Received one message: " + message);
context.ack();
}
});
}
}
- 也是先创建messagingAccessPoint，然后创建PushConsumer
- 也是通过resourceManager创建queue，然后跟PushConsumer绑定
- PushConsumer通过注册MessageListener来处理回调逻辑
StreamingConsumer
openmessaging-java/openmessaging-api-samples/src/main/java/io/openmessaging/samples/consumer/StreamingConsumerApp.java
public class StreamingConsumerApp {
public static void main(String[] args) throws OMSResourceNotExistException {
//Load and start the vendor implementation from a specific OMS driver URL.
final MessagingAccessPoint messagingAccessPoint =
OMS.getMessagingAccessPoint("oms:rocketmq://[email protected]/us-east");
messagingAccessPoint.startup();
//Fetch a ResourceManager to create Queue resource.
String targetQueue = "NS://HELLO_QUEUE";
ResourceManager resourceManager = messagingAccessPoint.resourceManager();
resourceManager.createQueue(targetQueue, OMS.newKeyValue());
//Fetch the streams of the target queue.
List streams = resourceManager.listStreams(targetQueue);
//Start a StreamingConsumer to iterate messages from the specific stream.
final StreamingConsumer streamingConsumer = messagingAccessPoint.createStreamingConsumer();
streamingConsumer.startup();
//Register a shutdown hook to close the opened endpoints.
Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
@Override
public void run() {
streamingConsumer.shutdown();
messagingAccessPoint.shutdown();
}
}));
assert streams.size() != 0;
StreamingIterator streamingIterator = streamingConsumer.seekToBeginning(streams.get(0));
while (streamingIterator.hasNext()) {
Message message = streamingIterator.next();
System.out.println("Received one message: " + message);
}
//All the messages in the stream has been consumed.
//Now consume the messages in reverse order
while (streamingIterator.hasPrevious()) {
Message message = streamingIterator.previous();
System.out.println("Received one message again: " + message);
}
}
}
- stream的这种方式跟kafka的使用方式有点类似
- 通过StreamingConsumer获取StreamingIterator，然后遍历获取消息
producer
Producer
openmessaging-java/openmessaging-api-samples/src/main/java/io/openmessaging/samples/producer/ProducerApp.java
public class ProducerApp {
public static void main(String[] args) {
final MessagingAccessPoint messagingAccessPoint =
OMS.getMessagingAccessPoint("oms:rocketmq://[email protected]/us-east");
final Producer producer = messagingAccessPoint.createProducer();
messagingAccessPoint.startup();
producer.startup();
//Register a shutdown hook to close the opened endpoints.
Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
@Override
public void run() {
producer.shutdown();
messagingAccessPoint.shutdown();
}
}));
//Sends a message to the specified destination synchronously.
{
SendResult sendResult = producer.send(producer.createBytesMessage(
"NS://HELLO_QUEUE", "HELLO_BODY".getBytes(Charset.forName("UTF-8"))));
System.out.println("Send sync message OK, message id is: " + sendResult.messageId());
}
//Sends a message to the specified destination asynchronously.
//And get the result through Future
{
final Future result = producer.sendAsync(producer.createBytesMessage(
"NS://HELLO_QUEUE", "HELLO_BODY".getBytes(Charset.forName("UTF-8"))));
final SendResult sendResult = result.get(3000L);
System.out.println("Send async message OK, message id is: " + sendResult.messageId());
}
//Sends a message to the specified destination asynchronously.
//And retrieve the result through FutureListener
{
final Future result = producer.sendAsync(producer.createBytesMessage(
"NS://HELLO_QUEUE", "HELLO_BODY".getBytes(Charset.forName("UTF-8"))));
result.addListener(new FutureListener() {
@Override
public void operationComplete(Future future) {
if (future.isDone() && null == future.getThrowable()) {
System.out.println("Send async message OK, message id is: " + future.get().messageId());
} else {
System.out.println("Send async message Failed, cause is: " + future.getThrowable().getMessage());
}
}
});
}
//Sends a message to the specific queue in OneWay manner.
{
//There is no {@code Future} related or {@code RuntimeException} thrown. The calling thread doesn't
//care about the send result and also have no context to get the result.
producer.sendOneway(producer.createBytesMessage(
"NS://HELLO_QUEUE", "HELLO_BODY".getBytes(Charset.forName("UTF-8"))));
}
}
}
- 通过messagingAccessPoint创建producer
- producer可以send、sendAsync以及sendOneway
- send是同步，sendAsync是异步，可以通过listener回调处理，sendOneway就是不关系发送结果
TransactionProducer
openmessaging-java/openmessaging-api-samples/src/main/java/io/openmessaging/samples/producer/TransactionProducerApp.java
public class TransactionProducerApp {
public static void main(String[] args) {
final MessagingAccessPoint messagingAccessPoint =
OMS.getMessagingAccessPoint("oms:rocketmq://[email protected]/us-east");
final Producer producer = messagingAccessPoint.createProducer();
messagingAccessPoint.startup();
producer.startup();
//Register a shutdown hook to close the opened endpoints.
Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
@Override
public void run() {
producer.shutdown();
messagingAccessPoint.shutdown();
}
}));
Message message = producer.createBytesMessage(
"NS://HELLO_QUEUE", "HELLO_BODY".getBytes(Charset.forName("UTF-8")));
//Sends a transaction message to the specified destination synchronously.
SendResult sendResult = producer.send(message, new LocalTransactionExecutor() {
@Override
public void execute(final Message message, final ExecutionContext context) {
//Do some local transaction
//Then commit this transaction and the message will be delivered.
context.commit();
}
@Override
public void check(final Message message, final CheckContext context) {
//The server may lookup the transaction status forwardly associated the specified message
context.commit();
}
}, OMS.newKeyValue());
System.out.println("Send transaction message OK, message id is: " + sendResult.messageId());
}
}
- 使用的还是Producer，只是send方法使用的是有LocalTransactionExecutor参数的方法，来发送事务消息
- LocalTransactionExecutor定义了execute和check方法
- execute方法用来做本地事务相关的操作；check方法用于检查本地事务的状态
routing
openmessaging-java/openmessaging-api-samples/src/main/java/io/openmessaging/samples/routing/RoutingApp.java
public class RoutingApp {
public static void main(String[] args) throws OMSResourceNotExistException {
//Load and start the vendor implementation from a specific OMS driver URL.
final MessagingAccessPoint messagingAccessPoint =
OMS.getMessagingAccessPoint("oms:rocketmq://[email protected]/us-east");
messagingAccessPoint.startup();
String destinationQueue = "NS://DESTINATION_QUEUE";
String sourceQueue = "NS://SOURCE_QUEUE";
//Fetch a ResourceManager to create source Queue, destination Queue, and the Routing instance.
ResourceManager resourceManager = messagingAccessPoint.resourceManager();
//Create the destination queue.
resourceManager.createQueue(destinationQueue, OMS.newKeyValue());
//Create the source queue.
resourceManager.createQueue(sourceQueue, OMS.newKeyValue());
KeyValue routingAttr = OMS.newKeyValue();
routingAttr.put(OMSBuiltinKeys.ROUTING_SOURCE, sourceQueue)
.put(OMSBuiltinKeys.ROUTING_DESTINATION, destinationQueue)
.put(OMSBuiltinKeys.ROUTING_EXPRESSION, "color = 'red'");
resourceManager.createRouting("NS://HELLO_ROUTING", routingAttr);
//Send messages to the source queue ahead of the routing
final Producer producer = messagingAccessPoint.createProducer();
producer.startup();
producer.send(producer.createBytesMessage(sourceQueue, "RED_COLOR".getBytes())
.putUserHeaders("color", "red"));
producer.send(producer.createBytesMessage(sourceQueue, "GREEN_COLOR".getBytes())
.putUserHeaders("color", "green"));
//Consume messages from the queue behind the routing.
final PushConsumer pushConsumer = messagingAccessPoint.createPushConsumer();
pushConsumer.startup();
pushConsumer.attachQueue(destinationQueue, new MessageListener() {
@Override
public void onReceived(Message message, Context context) {
//The message sent to the sourceQueue will be delivered to anotherConsumer by the routing rule
//In this case, the push consumer will only receive the message with red color.
System.out.println("Received a red message: " + message);
context.ack();
}
});
//Register a shutdown hook to close the opened endpoints.
Runtime.getRuntime().addShutdownHook(new Thread(new Runnable() {
@Override
public void run() {
producer.shutdown();
pushConsumer.shutdown();
messagingAccessPoint.shutdown();
}
}));
}
}
- routing用来做路由，可以通过表达式来从源队列过滤消息到目标队列，起到消息过滤的作用
小结
- open messaging没有定义kafka的topic相关的概念，也没有consumer group的概念
- amqp通过Exchange屏蔽了queue和topic的细节，不像JMS那样，需要producer去选择是要发到topic，还是发到queue
- 这里open messaging虽然没有定义exchange，但是由于没有topic概念，发送都是发送到queue
- open messaging的routing概念，跟amqp的outingKey有点类似，不过这个routing仅仅是作用于消息过滤，对消费者起作用
doc
- AMQP基本概念
- openmessaging.cloud
- OpenMessaging Runtime Interface for Java