什么是动态定时任务:是由客户制定生成的,服务端只知道该去执行什么任务,但任务的定时是不确定的(是由客户制定)。 
这样总不能修改配置文件每定制个定时任务就增加一个trigger吧,即便允许客户修改配置文件,但总需要重新启动web服务啊,研究了下Quartz在Spring中的动态定时,发现<bean id="cronTrigger" class="org.springframework.scheduling.quartz.CronTriggerBean" > 
         <property name="jobDetail" ref="schedulerJobDetail"/> 
         <property name="cronExpression"> 
             <value>0/10 * * * * ?</value> 
         </property> 
      中cronExpression是关键,如果可以动态设置cronExpression的值,也就说如果我们可以直接调用CronTriggerBean中设置cronExpression的方法,就可以顺利解决问题了。 
熟悉1的朋友可以跳过不看,下面2、3是动态定时任务的具体实现。 
 
1.  Quartz 在Spring中的简单配置 
Spring 配置文件: 
    <bean id="schedulerJobDetail" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean"> 
        <property name="targetObject" ref="scheduleInfoAction"/> 
        <property name="targetMethod" value="simpleJobTest"/> 
        <property name="concurrent" value="false"/> 
    </bean> 
    <bean id="cronTrigger" class="org.springframework.scheduling.quartz.CronTriggerBean" > 
         <property name="jobDetail" ref="schedulerJobDetail"/> 
         <property name="cronExpression"> 
             <value>0/10 * * * * ?</value> 
         </property> 
     </bean> 
    <bean id="schedulerFactory" class="org.springframework.scheduling.quartz.SchedulerFactoryBean"> 
        <property name="triggers"> 
            <list> 
                <ref local="cronTrigger"/> 
            </list> 
        </property> 
</bean> 
 
在上面的配置中设定了 
① targetMethod: 指定需要定时执行scheduleInfoAction中的simpleJobTest()方法 
② concurrent:对于相同的JobDetail,当指定多个Trigger时, 很可能第一个job完成之前,第二个job就开始了。指定concurrent设为false,多个job不会并发运行,第二个job将不会在第一个job完成之前开始。 
③ cronExpression:0/10 * * * * ?表示每10秒执行一次,具体可参考附表。 
④ triggers:通过再添加其他的ref元素可在list中放置多个触发器。 
 
scheduleInfoAction 中的simpleJobTest()方法 
注意:此方法没有参数,如果scheduleInfoAction有两个方法simpleJobTest()和simpleJobTest(String argument),则spring只会去执行无参的simpleJobTest(). 
public void simpleJobTest() {  
        log.warn("uh oh, Job is scheduled !'" + "' Success..."); 
    } 
 
2 .Quartz在Spring中动态设置cronTrigger方法一 
Spring 配置文件: 
<bean id="scheduleInfoAction" class="com.lively.happyoa.jobs.webapp.action.ScheduleInfoAction"> 
        <property name="scheduler" ref="schedulerFactory"/> 
        <property name="scheduleInfoManager" ref="scheduleInfoManager"/> 
    </bean> 
    <bean id="schedulerJobDetail" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean"> 
        <property name="targetObject" ref="scheduleInfoAction"/> 
        <property name="targetMethod" value="reScheduleJob"/> 
        <property name="concurrent" value="false"/> 
    </bean> 
    <bean id="cronTrigger" class="org.springframework.scheduling.quartz.CronTriggerBean" > 
         <property name="jobDetail" ref="schedulerJobDetail"/> 
         <property name="cronExpression"> 
             <value>0/10 * * * * ?</value> 
         </property> 
     </bean> 
    <bean id="schedulerFactory" class="org.springframework.scheduling.quartz.SchedulerFactoryBean"> 
        <property name="triggers"> 
            <list> 
                <ref local="cronTrigger"/> 
            </list> 
        </property> 
</bean> 
 
scheduleInfoAction 中的reScheduleJob ()方法及相关方法 
① reScheduleJob():读取数据库,获得自定义定时器调度时间 
    private void reScheduleJob() throws SchedulerException, ParseException { 
        // 运行时可通过动态注入的scheduler得到trigger 
        CronTriggerBean trigger = (CronTriggerBean) scheduler.getTrigger( 
                 "cronTrigger", Scheduler.DEFAULT_GROUP); 
        String dbCronExpression = getCronExpressionFromDB(); 
        String originConExpression = trigger.getCronExpression(); 
    // 判断从DB中取得的任务时间(dbCronExpression)和现在的quartz线程中的任务时间(originConExpression)是否相等 
    // 如果相等,则表示用户并没有重新设定数据库中的任务时间,这种情况不需要重新rescheduleJob 
        if(!originConExpression.equalsIgnoreCase(dbCronExpression)){ 
            trigger.setCronExpression(dbCronExpression); 
            scheduler.rescheduleJob("cronTrigger", Scheduler.DEFAULT_GROUP, trigger); 
        } 
    // 下面是具体的job内容,可自行设置 
    // executeJobDetail(); 
} 
 
② getCronExpressionFromDB():从数据库中获得dbCronExpression的具体代码,由于使用了scheduleInfoManager,所以要在定义相应的setter方法 
    private String getCronExpressionFromDB(){ 
        String sql="from ScheduleInfo scheduleInfo where 1=1 "; 
        sql=sql+" and scheduleInfo.infoId = '"+"1" + "'"; 
        List scheduleList = scheduleInfoManager.queryScheduleInListBySql(sql); 
        ScheduleInfo scheduleInfo = (ScheduleInfo)scheduleList.get(0); 
        String dbCronExpression = scheduleInfo.getCronExpression(); 
        return dbCronExpression; 
} 
 
③ 在spring配置文件的scheduleInfoAction配置了相应的property(scheduler/scheduleInfoManager),要为其设置setter方法 
    private Scheduler scheduler; 
    // 设值注入,通过setter方法传入被调用者的实例scheduler 
    public void setScheduler(Scheduler scheduler) { 
        this.scheduler = scheduler; 
     } 
    private ScheduleInfoManager scheduleInfoManager; 
    // 设值注入,通过setter方法传入被调用者的实例scheduleInfoManager 
    public void setScheduleInfoManager(ScheduleInfoManager scheduleInfoManager){ 
        this.scheduleInfoManager = scheduleInfoManager; 
    } 
 
3.  Quartz 在Spring中动态设置cronTrigger方法二 
在上面的2中我们可以看到,尽管 已经可以动态进行 rescheduleJob 了,不过依然需要我们设置一个 cronExpression ,如果尝试一下拿掉spring配置中的 
        <property name="cronExpression"> 
             <value>0/10 * * * * ?</value> 
         </property> 
则容器(如tomcat)启动时会报错。 
实际中我们希望tomcat启动时就可以直接去读数据库,拿到相应的 dbCronExpression ,然后定时执行一个job,而不希望配置初始的 cronExpression ,观察下面的 CronTriggerBean ,考虑到cronExpression需要初始化,如果设定一个类InitializingCronTrigger继承CronTriggerBean,然后在这个类中做一些读取DB的初始化工作(设置cronExpression),问题就可以解决了。 
 
Spring 配置文件: 
<bean id="scheduleInfoAction" class="com.lively.happyoa.jobs.webapp.action.ScheduleInfoAction"> 
        <property name="scheduler" ref="schedulerFactory"/> 
        <property name="scheduleInfoManager" ref="scheduleInfoManager"/> 
    </bean> 
    <bean id="schedulerJobDetail" class="org.springframework.scheduling.quartz.MethodInvokingJobDetailFactoryBean"> 
        <property name="targetObject" ref="scheduleInfoAction"/> 
        <property name="targetMethod" value="reScheduleJob"/> 
        <property name="concurrent" value="false"/> 
    </bean> 
     <bean id="cronTrigger" class="com.lively.happyoa.jobs.webapp.action.ScheduleInfoAction.InitializingCronTrigger"> 
         <property name="jobDetail" ref="schedulerJobDetail"/> 
         <!--<property name="cronExpression"> 
             <value>0/10 * * * * ?</value> 
         </property>--> 
         <property name="scheduleInfoManager" ref="scheduleInfoManager"/> 
     </bean> 
    <bean id="schedulerFactory" class="org.springframework.scheduling.quartz.SchedulerFactoryBean"> 
        <property name="triggers"> 
            <list> 
                <ref local="cronTrigger"/> 
            </list> 
        </property> 
</bean> 
 
InitializingCronTrigger 中的相关方法 
注意:在注入scheduleInfoManager属性的时候,我们可以去读取DB任务时间(之所以放在setter方法中,是因为需要在设置scheduleInfoManager后进行getCronExpressionFromDB(),否则,也可以①②逻辑把放在类的构造函数中). 
注意InitializingCronTrigger必须extendsCronTriggerBean. 
 
public class InitializingCronTrigger extendsCronTriggerBean implements Serializable { 
    private ScheduleInfoManager scheduleInfoManager; 
    // 设值注入,通过setter方法传入被调用者的实例scheduleInfoManager 
    public void setScheduleInfoManager(ScheduleInfoManager scheduleInfoManager){ 
        this.scheduleInfoManager = scheduleInfoManager; 
        // 因为在getCronExpressionFromDB使用到了scheduleInfoManager,所以 
        // 必须上一行代码设置scheduleInfoManager后进行getCronExpressionFromDB 
        String cronExpression = getCronExpressionFromDB ();   // ① 
        // 因为extendsCronTriggerBean ,此处调用父类方法初始化cronExpression 
        setCronExpression (cronExpression);                    // ② 
} 
    private String getCronExpressionFromDB(){ 
        String sql="from ScheduleInfo scheduleInfo where 1=1 "; 
        sql=sql+" and scheduleInfo.infoId = '"+"1" + "'"; 
        List scheduleList = scheduleInfoManager.queryScheduleInListBySql(sql); 
        ScheduleInfo scheduleInfo = (ScheduleInfo)scheduleList.get(0); 
        String dbCronExpression = scheduleInfo.getCronExpression(); 
        return dbCronExpression; 
 } 
…… 
} 
 
附表 CronTrigger Expression( 来自http://quartz.sourceforge.net/javadoc/org/quartz/CronTrigger.html) 
Expression 
 Meaning 
 
"0 0 12 * * ?" 
 Fire at 12pm (noon) every day 
 
"0 15 10 ? * *" 
 Fire at 10:15am every day 
 
"0 15 10 * * ?" 
 Fire at 10:15am every day 
 
"0 15 10 * * ? *" 
 Fire at 10:15am every day 
 
"0 15 10 * * ? 2005" 
 Fire at 10:15am every day during the year 2005 
 
"0 * 14 * * ?" 
 Fire every minute starting at 2pm and ending at 2:59pm, every day 
 
"0 0/5 14 * * ?" 
 Fire every 5 minutes starting at 2pm and ending at 2:55pm, every day 
 
"0 0/5 14,18 * * ?" 
 Fire every 5 minutes starting at 2pm and ending at 2:55pm, AND fire every 5 minutes starting at 6pm and ending at 6:55pm, every day 
 
"0 0-5 14 * * ?" 
 Fire every minute starting at 2pm and ending at 2:05pm, every day 
 
"0 10,44 14 ? 3 WED" 
 Fire at 2:10pm and at 2:44pm every Wednesday in the month of March. 
 
"0 15 10 ? * MON-FRI" 
 Fire at 10:15am every Monday, Tuesday, Wednesday, Thursday and Friday 
 
"0 15 10 15 * ?" 
 Fire at 10:15am on the 15th day of every month 
 
"0 15 10 L * ?" 
 Fire at 10:15am on the last day of every month 
 
"0 15 10 ? * 6L" 
 Fire at 10:15am on the last Friday of every month 
 
"0 15 10 ? * 6L" 
 Fire at 10:15am on the last Friday of every month 
 
"0 15 10 ? * 6L 2002-2005" 
 Fire at 10:15am on every last friday of every month during the years 2002, 2003, 2004 and 2005 
 
"0 15 10 ? * 6#3" 
 Fire at 10:15am on the third Friday of every month