用java写一下mq消息队列怎么接收

要使用Java接收MQ消息，您可以使用Java Message Service（JMS）API或使用MQ提供的Java API。

使用JMS API，您需要创建一个JMS连接并使用JMS会话来接收消息。以下是一个使用JMS API接收MQ消息的示例代码：

import javax.jms.*;
import org.apache.activemq.ActiveMQConnectionFactory;

public class MQConsumer {
    public static void main(String[] args) {
        ConnectionFactory connectionFactory = new ActiveMQConnectionFactory("tcp://localhost:61616");
        Connection connection = null;
        try {
            connection = connectionFactory.createConnection();
            connection.start();
            Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
            Destination destination = session.createQueue("QUEUE_NAME");
            MessageConsumer consumer = session.createConsumer(destination);
            Message message = consumer.receive();
            if (message instanceof TextMessage) {
                TextMessage textMessage = (TextMessage) message;
                System.out.println("Received message: " + textMessage.getText());
            }
        } catch (JMSException e) {
            e.printStackTrace();
        } finally {
            try {
                if (connection != null) {
                    connection.close();
                }
            } catch (JMSException e) {
                e.printStackTrace();
            }
        }
    }
}

请将上述代码中的"QUEUE_NAME"替换为您要接收消息的队列名称。

如果您想使用MQ提供的Java API，可以使用MQ的JAR文件并编写以下代码：

import com.ibm.mq.*;
import com.ibm.mq.constants.MQConstants;

public class MQConsumer {
    public static void main(String[] args) {
        MQQueueManager queueManager = null;
        MQQueue queue = null;
        MQMessage message = null;
        try {
            MQEnvironment.hostname = "MQ_HOSTNAME";
            MQEnvironment.channel = "MQ_CHANNEL";
            MQEnvironment.port = MQConstants.MQ_PORT;
            MQEnvironment.userID = "MQ_USERID";
            MQEnvironment.password = "MQ_PASSWORD";
            queueManager = new MQQueueManager("MQ_MANAGER");
            int openOptions = MQConstants.MQOO_INPUT_SHARED | MQConstants.MQOO_FAIL_IF_QUIESCING;
            queue = queueManager.accessQueue("QUEUE_NAME", openOptions);
            message = new MQMessage();
            MQGetMessageOptions getMessageOptions = new MQGetMessageOptions();
            getMessageOptions.options = MQConstants.MQGMO_WAIT;
            getMessageOptions.waitInterval = 5000;
            queue.get(message, getMessageOptions);
            String messageText = message.readStringOfByteLength(message.getMessageLength());
            System.out.println("Received message: " + messageText);
        } catch (MQException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (queue != null) {
                    queue.close();
                }
                if (queueManager != null) {
                    queueManager.disconnect();
                }
            } catch (MQException e) {
                e.printStackTrace();
            }
        }
    }
}

请将上述代码中的"MQ_HOSTNAME"，"MQ_CHANNEL"，"MQ_PORT"，"MQ_USERID"，"MQ_PASSWORD"，"MQ_MANAGER"和"QUEUE_NAME"替换为您MQ实例的相关信息和您要接收消息的队列名称。