rocketmq/docs/en/client/java/API_Reference_DefaultMQProducer.md

DefaultMQProducer

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Class introduction

public class DefaultMQProducer extends ClientConfig implements MQProducer

DefaultMQProducer is the entry point for an application to post messages. Out of the box, you can quickly create a producer with a no-argument constructor. It is mainly responsible for message sending and supports synchronous, asynchronous, and one-way sends. All of these send methods support batch sends. The parameters of the sender can be adjusted through the getter/setter methods provided by this class. DefaultMQProducer has multiple send methods, and each method is slightly different. Make sure you know the usage before you use it. Below is a producer example. See more examples.

public class Producer {
    public static void main(String[] args) throws MQClientException {
        // create a producer with producer_group_name
        DefaultMQProducer producer = new DefaultMQProducer("ProducerGroupName");

        // start the producer
        producer.start();

        for (int i = 0; i < 128; i++)
            try {
            	// construct the msg
                Message msg = new Message("TopicTest",
                        "TagA",
                        "OrderID188",
                        "Hello world".getBytes(RemotingHelper.DEFAULT_CHARSET));

                // send sync
                SendResult sendResult = producer.send(msg);

                // print the result
                System.out.printf("%s%n", sendResult);
            } catch (Exception e) {
                e.printStackTrace();
            }

        producer.shutdown();
    }
}

Note : This class is thread safe. It can be safely shared between multiple threads after configuration and startup is complete.

Variable

Type	Name	description
DefaultMQProducerImpl	defaultMQProducerImpl	The producer's internal default implementation
String	producerGroup	The producer's group
String	createTopicKey	Topics that do not exist on the server are automatically created when the message is sent
int	defaultTopicQueueNums	The default number of queues to create a topic
int	sendMsgTimeout	The timeout for the message to be sent
int	compressMsgBodyOverHowmuch	the threshold of the compress of message body
int	retryTimesWhenSendFailed	Maximum number of internal attempts to send a message in synchronous mode
int	retryTimesWhenSendAsyncFailed	Maximum number of internal attempts to send a message in asynchronous mode
boolean	retryAnotherBrokerWhenNotStoreOK	Whether to retry another broker if an internal send fails
int	maxMessageSize	Maximum length of message body
TraceDispatcher	traceDispatcher	Message trackers. Use rpcHook to track messages

construction method

Method name	Method description
DefaultMQProducer()	creates a producer with default parameter values
DefaultMQProducer(final String producerGroup)	creates a producer with producer group name.
DefaultMQProducer(final String producerGroup, boolean enableMsgTrace)	creates a producer with producer group name and set whether to enable message tracking
DefaultMQProducer(final String producerGroup, boolean enableMsgTrace, final String customizedTraceTopic)	creates a producer with producer group name and set whether to enable message tracking、the trace topic.
DefaultMQProducer(RPCHook rpcHook)	creates a producer with a rpc hook.
DefaultMQProducer(final String producerGroup, RPCHook rpcHook)	creates a producer with a rpc hook and producer group.
DefaultMQProducer(final String producerGroup, RPCHook rpcHook, boolean enableMsgTrace,final String customizedTraceTopic)	all of above.