Session session = connection.createSession(true,  Session.AUTO_ACKNOWLEDGE);

#不要进行事务提交
// session.commit()

1.第一次启动消费者，会正常消费一次
2.之后再启动6次消费者，都会消费到数据（默认6次）
3.第7次，无消息消费

ActiveMQConnection connection ...  // Create a connection

RedeliveryPolicy queuePolicy = new RedeliveryPolicy();
queuePolicy.setInitialRedeliveryDelay(0);
queuePolicy.setRedeliveryDelay(1000);
queuePolicy.setUseExponentialBackOff(false);
queuePolicy.setMaximumRedeliveries(2);

RedeliveryPolicy topicPolicy = new RedeliveryPolicy();
topicPolicy.setInitialRedeliveryDelay(0);
topicPolicy.setRedeliveryDelay(1000);
topicPolicy.setUseExponentialBackOff(false);
topicPolicy.setMaximumRedeliveries(3);

// Receive a message with the JMS API
RedeliveryPolicyMap map = connection.getRedeliveryPolicyMap();
map.put(new ActiveMQTopic(">"), topicPolicy);
map.put(new ActiveMQQueue(">"), queuePolicy);

@Component
@EnableJms
public class ActivemqConfig {
    
    //.....

	@Bean
    public RedeliveryPolicy redeliveryPolicy(){
        RedeliveryPolicy  redeliveryPolicy=   new RedeliveryPolicy();
        //是否在每次尝试重新发送失败后,增长这个等待时间
        redeliveryPolicy.setUseExponentialBackOff(true);
        //重发次数,默认为6次   这里设置为10次
        redeliveryPolicy.setMaximumRedeliveries(10);
        //重发时间间隔,默认为1秒
        redeliveryPolicy.setInitialRedeliveryDelay(1);
        //第一次失败后重新发送之前等待500毫秒,第二次失败再等待500 * 2毫秒,这里的2就是value
        redeliveryPolicy.setBackOffMultiplier(2);
        //是否避免消息碰撞
        redeliveryPolicy.setUseCollisionAvoidance(false);
        //设置重发最大拖延时间-1 表示没有拖延只有UseExponentialBackOff(true)为true时生效
        redeliveryPolicy.setMaximumRedeliveryDelay(-1);
        return redeliveryPolicy;
    }
}