pulsar java IO生产消费消息

新建一个maven工程

添加pulsar-client依赖：

pom.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>org.example</groupId>
    <artifactId>Pulsar_moudle</artifactId>
    <version>1.0-SNAPSHOT</version>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <configuration>
                    <source>8</source>
                    <target>8</target>
                </configuration>
            </plugin>
        </plugins>
    </build>

    <dependencies>
        <dependency>
            <groupId>org.apache.pulsar</groupId>
            <artifactId>pulsar-client</artifactId>
            <version>2.8.0</version>在这里插入代码片
        </dependency>
        <dependency>
            <groupId>org.apache.pulsar</groupId>
            <artifactId>pulsar-client-admin</artifactId>
            <version>2.8.0</version>
        </dependency>

    </dependencies>

</project>

启动pulsar单机模式

进入pulsar的安装目录，运行以下命令启动pulsar

bin/pulsar standalone

默认的URL为​​brokerServiceUrl=pulsar://localhost:6650/​​

可在client.conf 配置文件中修改

创建client 连接

pulsar启动后，默认的url为​​pulsar://localhost:6650​​

创建PulsarClient

       String Pulsar_URL="pulsar://localhost:6650";
        PulsarClient client = mkClient(Pulsar_URL);

其中mkClient函数如下：

   private static PulsarClient mkClient(String URL) {
        try {
            PulsarClient client = PulsarClient.builder()
                    .serviceUrl(URL)
                    .build();
            return client;
        } catch (PulsarClientException e) {
            e.printStackTrace();
        }
        return null;
    }

发送消息

   private static void send(PulsarClient client) throws PulsarClientException {
        Producer<String> producer=client.newProducer(Schema.STRING)
                .topic("my-topic")
                .create();
        Scanner input=new Scanner(System.in);
        for (int i=0;i<100;i++) {
            String str=input.next();
            producer.send(str+i);
            System.out.println("消息已发送");
        }

    }

接收消息

    private static void receive (PulsarClient client)  throws PulsarClientException {
        Consumer consumer = null;
            consumer = client.newConsumer()
                    .topic("my-topic")
                    .subscriptionName("my-subscription")
                    .subscribe();
        while (true){
            Message msg= null;
            try {
                msg = consumer.receive();
                System.out.println("Message received: " +new String(msg.getData()));
                //确认消息，以便删除已经接受的消息
                consumer.acknowledge(msg);
            } catch (PulsarClientException e) {
                //消息处理失败，请稍后重新传递
                consumer.negativeAcknowledge(msg);
            }
        }
    }

结果如下：

不阻塞主线程监听新消息

//不阻塞主线程而是不断地监听新消息
private static void receive_1 (PulsarClient client)  throws PulsarClientException {


    MessageListener myMessageListener = (consumer, msg) -> {
        try {
            System.out.println("Message received: " + new String(msg.getData()));
            consumer.acknowledge(msg);
        } catch (Exception e) {
            consumer.negativeAcknowledge(msg);
        }
    };

    Consumer consumer = client.newConsumer()
            .topic("my-topic")
            .subscriptionName("my-subscription")
            .messageListener(myMessageListener)
            .subscribe();
}

异步发送消息

    //异步发送消息
    private static void seend_asyn(PulsarClient client) throws PulsarClientException{
        Producer<byte[]> producer=client.newProducer()
                .topic("my-topic")
                .create();
        Scanner input=new Scanner(System.in);
        for (int i=0;i<100;i++) {
            String str=input.next();
            producer.sendAsync(str.getBytes()).thenAccept(msgId -> {
                System.out.println("Message with ID " + msgId + str+" successfully sent");
            });

        }

    }

异步消费消息

    //异步接收消息
    private static void receive_sync(PulsarClient client) throws PulsarClientException{
        Consumer consumer = null;

        consumer = client.newConsumer()
                .topic("my-topic")
                .subscriptionName("my-subscription")
                .subscribe();
        while (true){
            //异步接收消息
            CompletableFuture<Message> asyncMessage = null;
            asyncMessage=consumer.receiveAsync();
            System.out.println("Message reveived:"+ new String(asyncMessage.toString()));
            consumer.acknowledge((MessageId) asyncMessage);
        }



    }