EJB2和EJB3的不一样,而且好像和容器提供商也有关,这里给出的是适用于EJB3和JBoss4的:
@MessageDriven(activationConfig = {
@ActivationConfigProperty(
propertyName = "destinationType",
propertyValue = "javax.jms.Queue"),
@ActivationConfigProperty(
propertyName = "destination",
propertyValue = "queue/email"),
@ActivationConfigProperty(
propertyName = "maxSession",
propertyValue = "1")})
关键的就是那个maxSession,它控制实例的最大个数。