什么是動態(tài)定時任務(wù)：是由客戶制定生成的，服務(wù)端只知道該去執(zhí)行什么任務(wù)，但任務(wù)的定時是不確定的（是由客戶制定）。
這樣總不能修改配置文件每定制個定時任務(wù)就增加一個trigger吧，即便允許客戶修改配置文件，但總需要重新啟動web服務(wù)啊，研究了下Quartz在Spring中的動態(tài)定時，發(fā)現(xiàn)<bean id="cronTrigger" class="org.springframework.scheduling.quartz.CronTriggerBean" >
<property name="jobDetail" ref="schedulerJobDetail"/>
<property name="cronExpression">
<value>0/10 * * * * ?</value>
</property>
中cronExpression是關(guān)鍵，如果可以動態(tài)設(shè)置cronExpression的值，也就說如果我們可以直接調(diào)用CronTriggerBean中設(shè)置cronExpression的方法，就可以順利解決問題了。
熟悉1的朋友可以跳過不看，下面2、3是動態(tài)定時任務(wù)的具體實現(xiàn)。
1． Quartz 在Spring中的簡單配置
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>
在上面的配置中設(shè)定了
① targetMethod: 指定需要定時執(zhí)行scheduleInfoAction中的simpleJobTest()方法
② concurrent：對于相同的JobDetail，當(dāng)指定多個Trigger時, 很可能第一個job完成之前，第二個job就開始了。指定concurrent設(shè)為false，多個job不會并發(fā)運行，第二個job將不會在第一個job完成之前開始。
③ cronExpression：0/10 * * * * ?表示每10秒執(zhí)行一次，具體可參考附表。
④ triggers：通過再添加其他的ref元素可在list中放置多個觸發(fā)器。
scheduleInfoAction 中的simpleJobTest()方法
注意：此方法沒有參數(shù)，如果scheduleInfoAction有兩個方法simpleJobTest()和simpleJobTest(String argument)，則spring只會去執(zhí)行無參的simpleJobTest().
public void simpleJobTest() {
log.warn("uh oh, Job is scheduled !‘" + "‘ Success...");
}
2 ．Quartz在Spring中動態(tài)設(shè)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 ()方法及相關(guān)方法
① reScheduleJob():讀取數(shù)據(jù)庫，獲得自定義定時器調(diào)度時間
private void reScheduleJob() throws SchedulerException, ParseException {
// 運行時可通過動態(tài)注入的scheduler得到trigger
CronTriggerBean trigger = (CronTriggerBean) scheduler.getTrigger(
"cronTrigger", Scheduler.DEFAULT_GROUP);
String dbCronExpression = getCronExpressionFromDB();
String originConExpression = trigger.getCronExpression();
// 判斷從DB中取得的任務(wù)時間(dbCronExpression)和現(xiàn)在的quartz線程中的任務(wù)時間(originConExpression)是否相等
// 如果相等，則表示用戶并沒有重新設(shè)定數(shù)據(jù)庫中的任務(wù)時間，這種情況不需要重新rescheduleJob
if(!originConExpression.equalsIgnoreCase(dbCronExpression)){
trigger.setCronExpression(dbCronExpression);
scheduler.rescheduleJob("cronTrigger", Scheduler.DEFAULT_GROUP, trigger);
}
// 下面是具體的job內(nèi)容，可自行設(shè)置
// executeJobDetail();
}
② getCronExpressionFromDB()：從數(shù)據(jù)庫中獲得dbCronExpression的具體代碼，由于使用了scheduleInfoManager，所以要在定義相應(yīng)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配置了相應(yīng)的property（scheduler/scheduleInfoManager）,要為其設(shè)置setter方法
private Scheduler scheduler;
// 設(shè)值注入，通過setter方法傳入被調(diào)用者的實例scheduler
public void setScheduler(Scheduler scheduler) {
this.scheduler = scheduler;
}
private ScheduleInfoManager scheduleInfoManager;
// 設(shè)值注入，通過setter方法傳入被調(diào)用者的實例scheduleInfoManager
public void setScheduleInfoManager(ScheduleInfoManager scheduleInfoManager){
this.scheduleInfoManager = scheduleInfoManager;
}
3． Quartz 在Spring中動態(tài)設(shè)置cronTrigger方法二
在上面的2中我們可以看到，盡管 已經(jīng)可以動態(tài)進(jìn)行 rescheduleJob 了，不過依然需要我們設(shè)置一個 cronExpression ，如果嘗試一下拿掉spring配置中的
<property name="cronExpression">
<value>0/10 * * * * ?</value>
</property>
則容器（如tomcat）啟動時會報錯。
實際中我們希望tomcat啟動時就可以直接去讀數(shù)據(jù)庫，拿到相應(yīng)的 dbCronExpression ，然后定時執(zhí)行一個job，而不希望配置初始的 cronExpression ，觀察下面的 CronTriggerBean ，考慮到cronExpression需要初始化，如果設(shè)定一個類InitializingCronTrigger繼承CronTriggerBean，然后在這個類中做一些讀取DB的初始化工作（設(shè)置cronExpression），問題就可以解決了。
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 中的相關(guān)方法
注意：在注入scheduleInfoManager屬性的時候，我們可以去讀取DB任務(wù)時間（之所以放在setter方法中，是因為需要在設(shè)置scheduleInfoManager后進(jìn)行g(shù)etCronExpressionFromDB()，否則，也可以①②邏輯把放在類的構(gòu)造函數(shù)中）.
注意InitializingCronTrigger必須extendsCronTriggerBean.
public class InitializingCronTrigger extendsCronTriggerBean implements Serializable {
private ScheduleInfoManager scheduleInfoManager;
// 設(shè)值注入，通過setter方法傳入被調(diào)用者的實例scheduleInfoManager
public void setScheduleInfoManager(ScheduleInfoManager scheduleInfoManager){
this.scheduleInfoManager = scheduleInfoManager;
// 因為在getCronExpressionFromDB使用到了scheduleInfoManager，所以
// 必須上一行代碼設(shè)置scheduleInfoManager后進(jìn)行g(shù)etCronExpressionFromDB
String cronExpression = getCronExpressionFromDB (); // ①
// 因為extendsCronTriggerBean ，此處調(diào)用父類方法初始化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( 來自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
