spring配置文件中配置

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context"xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:aop="http://www.springframework.org/schema/aop"xmlns:task="http://www.springframework.org/schema/task"xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsdhttp://www.springframework.org/schema/contexthttp://www.springframework.org/schema/context/spring-context-4.2.xsdhttp://www.springframework.org/schema/mvchttp://www.springframework.org/schema/mvc/spring-mvc-4.2.xsdhttp://www.springframework.org/schema/aophttp://www.springframework.org/schema/aop/spring-aop-4.2.xsdhttp://www.springframework.org/schema/taskhttp://www.springframework.org/schema/task/spring-task-3.0.xsd"><bean class="com.wjz.quartz.RepayQuartz"/><task:annotation-driven/></beans>

定时任务处理类

packagecom.wjz.quartz;importorg.springframework.scheduling.annotation.Scheduled;public classRepayQuartz {@Scheduled(cron="0/10 * * * * ?")public voidrepay() {System.out.println("sping 定时任务");}
}

<task:annotation-driven/>标签使用TaskNamespaceHandler 来处理

public class TaskNamespaceHandler extendsNamespaceHandlerSupport {@Overridepublic voidinit() {　　　　　// 注册了一些解析器其中AnnotationDrivenBeanDefinitionParser解析@Scheduled注解this.registerBeanDefinitionParser("annotation-driven", newAnnotationDrivenBeanDefinitionParser());this.registerBeanDefinitionParser("executor", newExecutorBeanDefinitionParser());this.registerBeanDefinitionParser("scheduled-tasks", newScheduledTasksBeanDefinitionParser());this.registerBeanDefinitionParser("scheduler", newSchedulerBeanDefinitionParser());}}

注册了两个后置处理器

org.springframework.scheduling.annotation.AsyncAnnotationBeanPostProcessor

org.springframework.scheduling.annotation.ScheduledAnnotationBeanPostProcessor

我们主要来看ScheduledAnnotationBeanPostProcessor

我们可以看到他实现了BeanPostProcesser，ApplicationListener接口

先执行初始化后的后置处理

@Overridepublic Object postProcessAfterInitialization(finalObject bean, String beanName) {Class<?> targetClass =AopUtils.getTargetClass(bean);if (!this.nonAnnotatedClasses.contains(targetClass)) {　　　　　　　// 获得bean的所有的方法，获得方法信息和@Scheduled注解信息Map<Method, Set<Scheduled>> annotatedMethods =MethodIntrospector.selectMethods(targetClass,new MethodIntrospector.MetadataLookup<Set<Scheduled>>() {@Overridepublic Set<Scheduled>inspect(Method method) {Set<Scheduled> scheduledMethods =AnnotatedElementUtils.getMergedRepeatableAnnotations(method, Scheduled.class, Schedules.class);return (!scheduledMethods.isEmpty() ? scheduledMethods : null);}});if(annotatedMethods.isEmpty()) {this.nonAnnotatedClasses.add(targetClass);if(logger.isTraceEnabled()) {logger.trace("No @Scheduled annotations found on bean class: " +bean.getClass());}}else{for (Map.Entry<Method, Set<Scheduled>>entry : annotatedMethods.entrySet()) {Method method=entry.getKey();for(Scheduled scheduled : entry.getValue()) {　　　　　　　　　　　　　　// 处理加工方法和注解信息，后文详解processScheduled(scheduled, method, bean);}}if(logger.isDebugEnabled()) {logger.debug(annotatedMethods.size()+ " @Scheduled methods processed on bean '" + beanName +"': " +annotatedMethods);}}}returnbean;}

    protected voidprocessScheduled(Scheduled scheduled, Method method, Object bean) {try{Method invocableMethod=AopUtils.selectInvocableMethod(method, bean.getClass());　　　　　　　// 创建了一个Runnable对象，主要是用来反射定时方法的，后文详解#1Runnable runnable= newScheduledMethodRunnable(bean, invocableMethod);boolean processedSchedule = false;String errorMessage="Exactly one of the 'cron', 'fixedDelay(String)', or 'fixedRate(String)' attributes is required";// 初始化一个定时任务集合 Set<ScheduledTask> tasks = this.scheduledTasks.get(bean);if (tasks == null) {tasks= new LinkedHashSet<ScheduledTask>(4);this.scheduledTasks.put(bean, tasks);}//Determine initial delaylong initialDelay =scheduled.initialDelay();String initialDelayString=scheduled.initialDelayString();if(StringUtils.hasText(initialDelayString)) {Assert.isTrue(initialDelay< 0, "Specify 'initialDelay' or 'initialDelayString', not both");if (this.embeddedValueResolver != null) {initialDelayString= this.embeddedValueResolver.resolveStringValue(initialDelayString);}try{initialDelay=Long.parseLong(initialDelayString);}catch(NumberFormatException ex) {throw newIllegalArgumentException("Invalid initialDelayString value \"" + initialDelayString + "\" - cannot parse into integer");}}//解析表达式String cron =scheduled.cron();if(StringUtils.hasText(cron)) {Assert.isTrue(initialDelay== -1, "'initialDelay' not supported for cron triggers");processedSchedule= true;String zone=scheduled.zone();if (this.embeddedValueResolver != null) {cron= this.embeddedValueResolver.resolveStringValue(cron);zone= this.embeddedValueResolver.resolveStringValue(zone);}TimeZone timeZone;if(StringUtils.hasText(zone)) {timeZone=StringUtils.parseTimeZoneString(zone);}else{　　　　　　　　　　　　// 没有指定时区的话使用默认时区timeZone=TimeZone.getDefault();}　　　　　　　　　 // 将表达式解析成任务计划表填充到任务集合中，后文详解#2tasks.add(this.registrar.scheduleCronTask(new CronTask(runnable, newCronTrigger(cron, timeZone))));}//At this point we don't need to differentiate between initial delay set or not anymoreif (initialDelay < 0) {initialDelay= 0;}//Check fixed delaylong fixedDelay =scheduled.fixedDelay();if (fixedDelay >= 0) {Assert.isTrue(!processedSchedule, errorMessage);processedSchedule= true;tasks.add(this.registrar.scheduleFixedDelayTask(newIntervalTask(runnable, fixedDelay, initialDelay)));}String fixedDelayString=scheduled.fixedDelayString();if(StringUtils.hasText(fixedDelayString)) {Assert.isTrue(!processedSchedule, errorMessage);processedSchedule= true;if (this.embeddedValueResolver != null) {fixedDelayString= this.embeddedValueResolver.resolveStringValue(fixedDelayString);}try{fixedDelay=Long.parseLong(fixedDelayString);}catch(NumberFormatException ex) {throw newIllegalArgumentException("Invalid fixedDelayString value \"" + fixedDelayString + "\" - cannot parse into integer");}tasks.add(this.registrar.scheduleFixedDelayTask(newIntervalTask(runnable, fixedDelay, initialDelay)));}//Check fixed ratelong fixedRate =scheduled.fixedRate();if (fixedRate >= 0) {Assert.isTrue(!processedSchedule, errorMessage);processedSchedule= true;tasks.add(this.registrar.scheduleFixedRateTask(newIntervalTask(runnable, fixedRate, initialDelay)));}String fixedRateString=scheduled.fixedRateString();if(StringUtils.hasText(fixedRateString)) {Assert.isTrue(!processedSchedule, errorMessage);processedSchedule= true;if (this.embeddedValueResolver != null) {fixedRateString= this.embeddedValueResolver.resolveStringValue(fixedRateString);}try{fixedRate=Long.parseLong(fixedRateString);}catch(NumberFormatException ex) {throw newIllegalArgumentException("Invalid fixedRateString value \"" + fixedRateString + "\" - cannot parse into integer");}tasks.add(this.registrar.scheduleFixedRateTask(newIntervalTask(runnable, fixedRate, initialDelay)));}//Check whether we had any attribute set
Assert.isTrue(processedSchedule, errorMessage);}catch(IllegalArgumentException ex) {throw newIllegalStateException("Encountered invalid @Scheduled method '" + method.getName() + "': " +ex.getMessage());}}

书接前文#1

Runnable的run方法中是定时方法反射

@Overridepublic voidrun() {try{ReflectionUtils.makeAccessible(this.method);this.method.invoke(this.target);}catch(InvocationTargetException ex) {ReflectionUtils.rethrowRuntimeException(ex.getTargetException());}catch(IllegalAccessException ex) {throw newUndeclaredThrowableException(ex);}}

书接前文#2

创建一个CronTask任务对象，其中有Runnable对象和CronTrigger触发对象（表达式，时区），后文详解触发器的构造#2-1

publicScheduledTask scheduleCronTask(CronTask task) {ScheduledTask scheduledTask= this.unresolvedTasks.remove(task);boolean newTask = false;if (scheduledTask == null) {scheduledTask= newScheduledTask();newTask= true;}if (this.taskScheduler != null) {　　　　　　　 // 执行定时任务scheduledTask.future= this.taskScheduler.schedule(task.getRunnable(), task.getTrigger());}else{　　　　　　　 // 添加定时任务addCronTask(task);this.unresolvedTasks.put(task, scheduledTask);}return (newTask ? scheduledTask : null);}

再看监听处理

@Overridepublic voidonApplicationEvent(ContextRefreshedEvent event) {if (event.getApplicationContext() == this.applicationContext) {//Running in an ApplicationContext -> register tasks this late...//giving other ContextRefreshedEvent listeners a chance to perform//their work at the same time (e.g. Spring Batch's job registration).
finishRegistration();}}

this.registrar.afterPropertiesSet();

protected voidscheduleTasks() {if (this.taskScheduler == null) {　　　　　　　 // 初始化一个线程池调度器this.localExecutor =Executors.newSingleThreadScheduledExecutor();　　　　　　　 // 指定了任务调度器this.taskScheduler = new ConcurrentTaskScheduler(this.localExecutor);}if (this.triggerTasks != null) {for (TriggerTask task : this.triggerTasks) {addScheduledTask(scheduleTriggerTask(task));}}if (this.cronTasks != null) {for (CronTask task : this.cronTasks) {addScheduledTask(scheduleCronTask(task));}}if (this.fixedRateTasks != null) {for (IntervalTask task : this.fixedRateTasks) {addScheduledTask(scheduleFixedRateTask(task));}}if (this.fixedDelayTasks != null) {for (IntervalTask task : this.fixedDelayTasks) {addScheduledTask(scheduleFixedDelayTask(task));}}}

publicScheduledTask scheduleCronTask(CronTask task) {ScheduledTask scheduledTask= this.unresolvedTasks.remove(task);boolean newTask = false;if (scheduledTask == null) {scheduledTask= newScheduledTask();newTask= true;}　　　　　// 这次指定了ConcurrentTaskScheduler任务调度器，开始调度定时任务if (this.taskScheduler != null) {scheduledTask.future= this.taskScheduler.schedule(task.getRunnable(), task.getTrigger());}else{addCronTask(task);this.unresolvedTasks.put(task, scheduledTask);}return (newTask ? scheduledTask : null);}

@Overridepublic ScheduledFuture<?>schedule(Runnable task, Trigger trigger) {try{if (this.enterpriseConcurrentScheduler) {return new EnterpriseConcurrentTriggerScheduler().schedule(decorateTask(task, true), trigger);}else{ErrorHandler errorHandler= (this.errorHandler != null ? this.errorHandler : TaskUtils.getDefaultErrorHandler(true));　　　　　　　　　 // 这里就是核心的地方了， Runnable的run方法内，定时调用自己的run方法实现功能，巧妙之极return new ReschedulingRunnable(task, trigger, this.scheduledExecutor, errorHandler).schedule();}}catch(RejectedExecutionException ex) {throw new TaskRejectedException("Executor [" + this.scheduledExecutor + "] did not accept task: " +task, ex);}}

public ScheduledFuture<?>schedule() {synchronized (this.triggerContextMonitor) {　　　　　　　 // 拿到下一次执行任务的时间，后文详解#2-2this.scheduledExecutionTime = this.trigger.nextExecutionTime(this.triggerContext);if (this.scheduledExecutionTime == null) {return null;}　　　　　　　 // 固定延迟即延迟多长时间执行long initialDelay = this.scheduledExecutionTime.getTime() -System.currentTimeMillis();this.currentFuture = this.executor.schedule(this, initialDelay, TimeUnit.MILLISECONDS);return this;}}@Overridepublic voidrun() {Date actualExecutionTime= newDate();　　　　　// 这就是上文所提到的定时方法反射执行定时业务方法super.run();Date completionTime= newDate();synchronized (this.triggerContextMonitor) {　　　　　　　 // 记录上一次任务执行的时间this.triggerContext.update(this.scheduledExecutionTime, actualExecutionTime, completionTime);if (!this.currentFuture.isCancelled()) {　　　　　　　　　 // 继续无限调度schedule();}}}

书接前文#2-1

CronTrigger触发对象的构造，初始化了计划时间表生成器

publicCronTrigger(String expression, TimeZone timeZone) {this.sequenceGenerator = newCronSequenceGenerator(expression, timeZone);}

publicCronSequenceGenerator(String expression, TimeZone timeZone) {this.expression =expression;this.timeZone =timeZone;　　　　　// 解析表达式生成计划时间表parse(expression);}

private void parse(String expression) throwsIllegalArgumentException {String[] fields= StringUtils.tokenizeToStringArray(expression, " ");if (!areValidCronFields(fields)) {throw newIllegalArgumentException(String.format("Cron expression must consist of 6 fields (found %d in \"%s\")", fields.length, expression));}　　　　　// 主要使用了BitSet来制造计划时间表setNumberHits(this.seconds, fields[0], 0, 60);setNumberHits(this.minutes, fields[1], 0, 60);setNumberHits(this.hours, fields[2], 0, 24);setDaysOfMonth(this.daysOfMonth, fields[3]);setMonths(this.months, fields[4]);setDays(this.daysOfWeek, replaceOrdinals(fields[5], "SUN,MON,TUE,WED,THU,FRI,SAT"), 8);if (this.daysOfWeek.get(7)) {//Sunday can be represented as 0 or 7this.daysOfWeek.set(0);this.daysOfWeek.clear(7);}}

private void setNumberHits(BitSet bits, String value, int min, intmax) {String[] fields= StringUtils.delimitedListToStringArray(value, ",");for(String field : fields) {　　　　　　　// 检查是否包含'/',不包含的话列出最小值到最大值的范围if (!field.contains("/")) {//Not an incrementer so it must be a range (possibly empty)int[] range =getRange(field, min, max);bits.set(range[0], range[1] + 1);}else{// 包含'/'的话列出每xx秒（或分、时）的时间表如{0,10,20,30,40,50}String[] split= StringUtils.delimitedListToStringArray(field, "/");if (split.length > 2) {throw new IllegalArgumentException("Incrementer has more than two fields: '" +field+ "' in expression \"" + this.expression + "\"");}int[] range = getRange(split[0], min, max);if (!split[0].contains("-")) {range[1] = max - 1;}int delta = Integer.valueOf(split[1]);if (delta <= 0) {throw new IllegalArgumentException("Incrementer delta must be 1 or higher: '" +field+ "' in expression \"" + this.expression + "\"");}　　　　　　　　　 // 以一定数值叠加为BitSet赋值for (int i = range[0]; i <= range[1]; i +=delta) {bits.set(i);}}}}

private int[] getRange(String field, int min, intmax) {int[] result = new int[2];　　　　　// 包含*就是最大到最小if (field.contains("*")) {result[0] =min;result[1] = max - 1;returnresult;}　　　　　// 不包含'/'和'-'返回值if (!field.contains("-")) {result[0] = result[1] =Integer.valueOf(field);}else{String[] split= StringUtils.delimitedListToStringArray(field, "-");if (split.length > 2) {throw new IllegalArgumentException("Range has more than two fields: '" +field+ "' in expression \"" + this.expression + "\"");}result[0] = Integer.valueOf(split[0]);result[1] = Integer.valueOf(split[1]);}if (result[0] >= max || result[1] >=max) {throw new IllegalArgumentException("Range exceeds maximum (" + max + "): '" +field+ "' in expression \"" + this.expression + "\"");}if (result[0] < min || result[1] <min) {throw new IllegalArgumentException("Range less than minimum (" + min + "): '" +field+ "' in expression \"" + this.expression + "\"");}if (result[0] > result[1]) {throw new IllegalArgumentException("Invalid inverted range: '" + field +"' in expression \"" + this.expression + "\"");}returnresult;}

书接前文#2-2

拿到下一个执行调度的时间

@OverridepublicDate nextExecutionTime(TriggerContext triggerContext) {　　　　　// 拿到上一次执行调度的时间Date date=triggerContext.lastCompletionTime();if (date != null) {Date scheduled=triggerContext.lastScheduledExecutionTime();if (scheduled != null &&date.before(scheduled)) {date =scheduled;}}else{　　　　　　　 // 没拿到的话就拿当前时间date= newDate();}　　　　　// 拿到一下一次执行调度的时间return this.sequenceGenerator.next(date);}

publicDate next(Date date) {Calendar calendar= newGregorianCalendar();calendar.setTimeZone(this.timeZone);calendar.setTime(date);calendar.set(Calendar.MILLISECOND, 0);long originalTimestamp =calendar.getTimeInMillis();　　　　　// 为日历设置下一次执行调度的时间doNext(calendar, calendar.get(Calendar.YEAR));if (calendar.getTimeInMillis() ==originalTimestamp) {calendar.add(Calendar.SECOND, 1);doNext(calendar, calendar.get(Calendar.YEAR));}// 返回设置好下一次调度的日历时间returncalendar.getTime();}

private void doNext(Calendar calendar, intdot) {List<Integer> resets = new ArrayList<Integer>();// 拿到当前时间的秒数int second =calendar.get(Calendar.SECOND);List<Integer> emptyList =Collections.emptyList();　　　　　// 拿到下一次执行调度的秒数int updateSecond = findNext(this.seconds, second, calendar, Calendar.SECOND, Calendar.MINUTE, emptyList);if (second ==updateSecond) {resets.add(Calendar.SECOND);}int minute =calendar.get(Calendar.MINUTE);int updateMinute = findNext(this.minutes, minute, calendar, Calendar.MINUTE, Calendar.HOUR_OF_DAY, resets);if (minute ==updateMinute) {resets.add(Calendar.MINUTE);}else{doNext(calendar, dot);}int hour =calendar.get(Calendar.HOUR_OF_DAY);int updateHour = findNext(this.hours, hour, calendar, Calendar.HOUR_OF_DAY, Calendar.DAY_OF_WEEK, resets);if (hour ==updateHour) {resets.add(Calendar.HOUR_OF_DAY);}else{doNext(calendar, dot);}int dayOfWeek =calendar.get(Calendar.DAY_OF_WEEK);int dayOfMonth =calendar.get(Calendar.DAY_OF_MONTH);int updateDayOfMonth = findNextDay(calendar, this.daysOfMonth, dayOfMonth, daysOfWeek, dayOfWeek, resets);if (dayOfMonth ==updateDayOfMonth) {resets.add(Calendar.DAY_OF_MONTH);}else{doNext(calendar, dot);}int month =calendar.get(Calendar.MONTH);int updateMonth = findNext(this.months, month, calendar, Calendar.MONTH, Calendar.YEAR, resets);if (month !=updateMonth) {if (calendar.get(Calendar.YEAR) - dot > 4) {throw new IllegalArgumentException("Invalid cron expression \"" + this.expression +"\" led to runaway search for next trigger");}doNext(calendar, dot);}}

private int findNext(BitSet bits, int value, Calendar calendar, int field, int nextField, List<Integer>lowerOrders) {　　　　　// 拿到下一个执行调度的秒数如当前时间的秒数是23任务是每10秒调度则拿到30，如果是58则返回-1int nextValue =bits.nextSetBit(value);        if (nextValue == -1) {　　　　　　　 // 加一分（时，日）calendar.add(nextField,1);　　　　　　　 // 重置秒（分、时）reset(calendar, Arrays.asList(field));nextValue= bits.nextSetBit(0);}if (nextValue !=value) {　　　　　　　 // 为日历设置下一个执行调度的秒（分、时）数calendar.set(field, nextValue);reset(calendar, lowerOrders);}returnnextValue;}