final Properties partitionsInfo = new Properties();
partitionsInfo.put("topic.num.exampleTopic1", "0:4;1:4");
metaClientConfig.setPartitionsInfo(partitionsInfo);
// New session factory,ǿ�ҽ���ʹ�õ���
final OrderedMessageSessionFactory sessionFactory = new OrderedMetaMessageSessionFactory(metaClientConfig);
// create producer,ǿ�ҽ���ʹ�õ���
final MessageProducer producer = sessionFactory.createProducer(new CustomPartitionSelector());
// publish topic
final String topic = "meta-test";
producer.publish(topic);