JMS感触

JMS感触:

看一家公司的招聘上写着"熟悉JEE规范如servlet, JMS, EJB等",这三个中的servlet最熟悉,基于的此那些框架也深入地研究学习过,EJB虽然没在项目中用过,但自己对这块还算了解,知道EJB的组成及其背后的一些原理,JMS就迷糊了,只知道它跟EJB中有一种Bean(也就是"Message-Driven Beans MDB")有联系,再往深的,那为什么要提出这个JMS概念?这个概念与MDB有什么联系?怎么使用?

中有下面一段对JMS的介绍:
It’s 4:55 PM on Friday. You’re only minutes away from starting a much-anticipated
vacation. You have just enough time to drive to the airport and catch your flight.
But before you pack up and head out, you need to be sure that your boss and col-
leagues know the status of the work you’ve been doing so that they can pick up
where you left off on Monday. Unfortunately, some of your colleagues have
already skipped out for an early weekend departure... and your boss is tied up in a
meeting. What do you do?
 You could call your boss’s cell phone... but it’s not necessary to interrupt his
meeting for a mere status report. Maybe you could stick around and wait until he
returns from the meeting. But it’s anyone’s guess how long the meeting will last
and you have a plane to catch. Or perhaps you could leave a sticky note on his
monitor... right next to 100 other sticky notes that it will blend in with.
 The most practical way to communicate your status and still catch your plane is
to send a quick email to your boss and your colleagues, detailing your progress
and promising to send a postcard. You don’t know where they are or when they’ll
actually read the email, but you do know that they’ll eventually return to their
desk and read it. Meanwhile, you’re on your way to the airport.
 Sometimes it’s necessary to talk to someone directly. If you injure yourself and
need an ambulance, you’re probably going to pick up the phone-emailing the
hospital just won’t do. Often, however, sending a message is sufficient and offers
some advantages over direct communication-such as letting you get on with
your vacation.
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That's it!就是想要这种感觉,深入浅出,形象易懂,很好地讲述了JMS与现有技术的关联.