Oracle神谕

    而在Spring里，已经很好的集成了Quartz，简单到像配cron一样，在xml文件里面配一下时间就可以自动执行，不需要写一行代码。Spring对Quartz大刀阔斧的简化堪称范例，Quartz项目组也许可以学习一下。

    <bean id="methodInvokingJobDetail"
        class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean">
        <property name="targetObject"><ref bean="financeDAO"/></property>
        <property name="targetMethod"><value>confirmOrder</value></property>
    </bean>

    <bean id="cronTrigger" class="org.springframework.scheduling.quartz.CronTriggerBean">
        <property name="jobDetail">
            <ref bean="methodInvokingJobDetail"/>
        </property>
        <property name="cronExpression">
            <value>0 0 6,12,20 * * ?</value>
        </property>
    </bean>

    <bean class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
        <property name="triggers">
            <list><ref local="cronTrigger"/></list>
        </property>
    </bean>

上面这段配置文件规定了在早上6点和晚上8点执行financeDAO对象的confirmOrder()方法.

附：cronExpression配置说明

字段		允许值		允许的特殊字符
秒		0-59		, - * /
分		0-59		, - * /
小时		0-23		, - * /
日期		1-31		, - * ? / L W C
月份		1-12 或者 JAN-DEC		, - * /
星期		1-7 或者 SUN-SAT		, - * ? / L C #
年（可选）		留空, 1970-2099		, - * /

TriggerListeners and JobListeners
Listeners are objects that you create to perform actions based on events occuring within the scheduler. As you can probably guess, TriggerListeners receive events related to trigger,and JobListners receive events related to jobs.

Trigger-related events include: trigger firings,trigger mis-firings(discussed in the "Triggers" sections of this document),and trigger completions (the jobs fired off by the trigger is finished).

To create a listener,simply create an object the implements either the org.quartz.TriggerListener and/or org.quartz.JobListener interface. Listeners are then registered with the scheduler during run time ,and must be given a name(or rather ,they must advertise their own name via their getName()method.  Listeners can be registered as either "global" or "non-global". Global listeners receive events for ALL triggers/jobs, and non-global listeners receive events only for the specific triggers/jobs that explicitely name the listener in their getTriggerListenerNames() or getJobListenerNames() properties.

 scheduler.addGlobalJobListener(myJobListener);
or
 scheudler.addJobListener(myJobListener);
 
Listeners are not used by most users of Quartz,but are handy when application requirements create the need for the notification of events,without the Job itself explicitly nofifying the application.

More About CronTrigger
更多关于CronTrigger

CronTriggers are often more useful than SimpleTrigger, if you need a job-firing schedule that recurs based on calendar-like notions, rather than on the exactly specified intervals of SimpleTrigger.
CronTriggers 比SimpleTrigger经常更加有用,如果你需要一个基于像日历概念的重复 job-firing 调度，而不是在一个SimpleTrigger特定的间隔。

With CronTrigger, you can specify firing-schedules such as "every Friday at noon", or "every weekday and 9:30 am", or even "every 5 minutes between 9:00 am and 10:00 am on every Monday, Wednesday and Friday".
使用CronTrigger,你可以限定firing-schedulers例如 “每天中午“，或者”，”每天周日上午9:30“，或者甚至 “每5分钟在上午9：00 到 10：00 每周一、周三、周五”

Cron Expressions
Cron 表达式

Cron-Expressions are used to configure instances of CronTrigger. Cron-Expressions are strings that are actually made up of six sub-expressions, that describe individual details of the schedule. These sub-expression are separated with white-space, and represent:
Cron 表达式被用来注册CronTrigger实例的。Cron表达式是字符串，它由六个子表达式组成，它描述了不同的调度细节。这些子表达式被白色表达式隔开，表现：

Seconds  秒
Minutes  分
Hours    时
Day-of-Month  日
Month         月
Day-of-Week   周

An example of a complete cron-expression is the string "0 0 12 ? * WED" - which means "every Wednesday at 12:00 pm".
一个完整的Cron 表达式例子是字符串“0 0 12 ? * WEB” 意味着每周三上午12：00。

Individual sub-expressions can contain ranges and/or lists. For example, the day of week field in the previous (which reads "WED") example could be replaces with "MON-FRI", "MON, WED, FRI", or even "MON-WED,SAT".
单独的子表达式可以包含平行的 和/或。例如，在上一个例子一周的一天字段（它读作"WED"）可以被“MON-FRI”,"MON,WED,FRI"，或者甚至"MON-WED,SAT"替换掉。

Wild-cards (the '*' character) can be used to say "every" possible value of this field. Therefore the '*' character in the "Month" field of the previous example simply means "every month". A '*' in the Day-Of-Week field would obviously mean "every day of the week".
统配符（"*"字符）可以被用来作为这个字段的"每一个"可能值。所以,在上一个例子月字段中的"*"字符表示每个月。 一个"*"在周天将明显意味着周的每一天。

All of the fields have a set of valid values that can be specified. These values should be fairly obvious - such as the numbers 0 to 59 for seconds and minutes, and the values 0 to 23 for hours. Day-of-Month can be any value 0-31, but you need to be careful about how many days are in a given month! Months can be specified as values between 0 and 11, or by using the strings JAN, FEB, MAR, APR, MAY, JUN, JUL, AUG, SEP, OCT, NOV and DEC. Days-of-Week can be specified as vaules between 1 and 7 (1 = Sunday) or by using the strings SUN, MON, TUE, WED, THU, FRI and SAT.
所有字段都用一个合法限定的值。这些值应该是明显的，例如0到59数字为秒和分的限定，0到23为小时。月的某天可以是0-31的，或者你需要消息给个月有多少天！月份可以被限定在0到11，或者，使用英文字符串缩写。一个礼拜的一天可以被限定作为1到7（1=Sunnday）或者使用英文字符串。

The '/' character can be used to specify increments to values. For example, if you put '0/15' in the Minutes field, it means 'every 15 minutes, starting at minute zero'. If you used '3/20' in the Minutes field, it would mean 'every 20 minutes during the hour, starting at minute three' - or in other words it is the same as specifying '3,23,43' in the Minutes field.
"/"字符可以内用来限定值的增加。例如，如果你将'0/15'放到分钟字段，它意味着"每15分钟，开始于0分钟"。如果你使用"3/20"在分钟字段中，你将意味着"一个小时内每20分钟，开始于3分钟"---  或者换言之，它和在分钟字段"3,23,43"限定是一样的。

The '?' character is allowed for the day-of-month and day-of-week fields. It is used to specify "no specific value". This is useful when you need to specify something in one of the two fields, but not the other. See the examples below (and CronTrigger JavaDOC) for clarification.

"?"字符是允许为月的某一天或者周的某一天字段的。它被用来限定"没有限定值"。这是有用的，当你需要限定一些事情在一个或两个字段中，但不是这里的。

The 'L' character is allowed for the day-of-month and day-of-week fields. This character is short-hand for "last", but it has different meaning in each of the two fields. For example, the value "L" in the day-of-month field means "the last day of the month" - day 31 for January, day 28 for February on non-leap years. If used in the day-of-week field by itself, it simply means "7" or "SAT". But if used in the day-of-week field after another value, it means "the last xxx day of the month" - for example "6L" or "FRIL" both mean "the last friday of the month". When using the 'L' option, it is important not to specify lists, or ranges of values, as you'll get confusing results.

"L"字符是允许用来月某天和周某天字段。这个字符是一个"last"的缩写，但是它有不同的意义在两个字段的其中之一。例如，这个值"L"在月字段的某一天意味着" 这个月的最后一天"，31或者28等等。

Here are a few more examples of expressions and their meanings - you can find even more in the JavaDOC for CronTrigger

CronTrigger Example 1 - an expression to create a trigger that simply fires every 5 minutes

  "0 0/5 * * * ?"

CronTrigger Example 2 - an expression to create a trigger that fires every 5 minutes, at 10 seconds after the minute (i.e. 10:00:10 am, 10:05:10 am, etc.).

  "10 0/5 * * * ?"

CronTrigger Example 3 - an expression to create a trigger that fires at 10:30, 11:30, 12:30, and 13:30, on every Wednesday and Friday.

  "0 30 10-13 ? * WED,FRI"

CronTrigger Example 4 - an expression to create a trigger that fires every half hour between the hours of 8 am and 10 am on the 5th and 20th of every month. Note that the trigger will NOT fire at 10:00 am, just at 8:00, 8:30, 9:00 and 9:30

  "0 0/30 8-9 5,20 * ?"

Note that some scheduling requirements are too complicated to express with a single trigger - such as "every 5 minutes between 9:00 am and 10:00 am, and every 20 minutes between 1:00 pm and 10:00 pm". The solution in this scenario is to simply create two triggers, and register both of them to run the same job.

What is Quartz? (什么是Quartz?)
Quartz is a full-featured, open source job scheduling system that can be integrated with, or used along side virtually any J2EE or J2SE application - from the smallest stand-alone application to the largest e-commerce system. Quartz can be used to create simple or complex schedules for executing tens, hundreds, or even tens-of-thousands of jobs; jobs whose tasks are defined as standard Java components or EJBs. The Quartz Scheduler includes many enterprise-class features, such as JTA transactions and clustering.

Quartz 是一个功能齐全的、开源的job时间调度系统，它可以被结合的,或者伴随虚拟的任何J2EE或J2SE程序-从最小的独立的应用程序到最大的e-commerce系统被使用。Quartz可以用来创建简单或复杂的时间调度来执行十、百、千、甚至上万的jobs;获得的job被定义为一个标准的java组件或EJBs. 这个Quartz 时间调度包含很多企业类的特征，例如JTA事务和簇。

The licensing of Quartz versions 1.0 through 1.4.5 is similar to both the BSD and ASF (Apache) public licenses, which means it's free for use, even within commercial products.

Quartz 1.0版本到1.4.5版本的licensing 是类似与BSD和ASF(apache)公共licenses, 它意味着可以免费使用，甚至使用在商业产品中使用。
With the upcoming release of version 1.5.0, Quartz is moving to the Apache 2.0 license.
伴随1.5.0版本的发布，Quartz将转移向apache 2.0 的license.

What can Quartz do for you? (Quartz可以为你做什么？)
If your application has tasks that need to occur at given moments in time, or if your system has recurring maintenance jobs then Quartz may be your ideal solution.

如果你的程序有一些这样的任务，它需要及时地发生在给定时间，或者你如果你的系统有连续维护jobs，那么Quartz可以成为你的理想的解决方案。

Sample uses of job scheduling with Quartz:
Quartz使用job时间调度的范例

Driving Workflow: As a new order is initially placed, schedule a Job to fire in exactly 2 hours, that will check the status of that order, and trigger a warning notification if an order confirmation message has not yet been received for the order, as well as changing the order's status to 'awaiting intervention'.
System Maintenance: Schedule a job to dump the contents of a database into an XML file every business day (all weekdays except holidays) at 11:30 PM.

工作流驱动：作为一个新的订单被初始化放置，调度一个job去工作在正好两个小时内，它将检查订单的状态，并且触发一个警告通知如果订单确认信息没有被接收，又改变订单的状态到"等待干涉"。
系统维护：调度一个job来将数据库转化为XML文件 每商业日期（所有周末除了节假日）在下午11：30。