java Spring定时任务Quartz执行过程是什么

这篇文章主要介绍"java Spring定时任务Quartz执行过程是什么"，在日常操作中，相信很多人在java Spring定时任务Quartz执行过程是什么问题上存在疑惑，小编查阅了各式资料，整理出简单好用的操作方法，希望对大家解答"java Spring定时任务Quartz执行过程是什么"的疑惑有所帮助！接下来，请跟着小编一起来学习吧！

一、前言介绍

在日常开发中经常会用到定时任务，用来；库表扫描发送MQ、T+n账单结算、缓存数据更新、秒杀活动状态变更，等等。因为有了Spring的Schedule极大的方便了我们对这类场景的使用。那么，除了应用你还了解它多少呢；

1. 默认初始化多少个任务线程

2. JobStore有几种实现，你平时用的都是哪个

3. 一个定时任务的执行流程简述下

二、案例工程

为了更好的做源码分析，我们将平时用的定时任务服务单独抽离出来。

 1itstack-demo-code-schedule
 2└── src
 3    ├── main
 4    │   ├── java
 5    │   │   └── org.itstack.demo
 6    │   │       ├── DemoTask.java
 7    │   │       └── JobImpl.java   
 8    │   └── resources    
 9    │       ├── props    
10    │       │   └── config.properties
11    │       ├── spring
12    │       │   └── spring-config-schedule-task.xml
13    │       ├── logback.xml
14    │       └── spring-config.xml
15    └── test
16         └── java
17             └── org.itstack.demo.test
18                 ├── ApiTest.java
19                 ├── MyQuartz.java                
20                 └── MyTask.java

三、环境配置

1. JDK 1.8

2. IDEA 2019.3.1

3. Spring 4.3.24.RELEASE

4. quartz 2.3.2 ｛不同版本略有代码差异｝

四、源码分析

1
2    org.quartz-scheduler
3    quartz
4    2.3.2
5

依赖于Spring版本升级quartz选择2.3.2，同时如果你如本文案例中所示使用xml配置任务。那么会有如下更改；

Spring 3.x/org.springframework.scheduling.quart.CronTriggerBean

1 
2     
3     
4 

Spring 4.x/org.springframework.scheduling.quartz.CronTriggerFactoryBean

1 
2     
3     
4 

在正式分析前，可以看下quartz的默认配置，很多初始化动作都要从这里取得参数，同样你可以配置自己的配置文件。例如，当你的任务很多时，默认初始化的10个线程组不满足你的业务需求，就可以按需调整。

quart.properties

 1# Default Properties file for use by StdSchedulerFactory
 2# to create a Quartz Scheduler Instance, if a different
 3# properties file is not explicitly specified.
 4#
 5
 6org.quartz.scheduler.instanceName: DefaultQuartzScheduler
 7org.quartz.scheduler.rmi.export: false
 8org.quartz.scheduler.rmi.proxy: false
 9org.quartz.scheduler.wrapJobExecutionInUserTransaction: false
10
11org.quartz.threadPool.class: org.quartz.simpl.SimpleThreadPool
12org.quartz.threadPool.threadCount: 10
13org.quartz.threadPool.threadPriority: 5
14org.quartz.threadPool.threadsInheritContextClassLoaderOfInitializingThread: true
15
16org.quartz.jobStore.misfireThreshold: 60000
17
18org.quartz.jobStore.class: org.quartz.simpl.RAMJobStore

1. 从一个简单案例开始

平时我们使用Schedule基本都是注解或者xml配置文件，但是为了可以更简单的分析代码，我们从一个简单的Demo入手，放到main函数中。

DemoTask.java & 定义一个等待被执行的任务

1public class DemoTask {
2
3    private Logger logger = LoggerFactory.getLogger(DemoTask.class);
4
5    public void execute() throws Exception{
6        logger.info("定时处理用户信息任务：0/5 * * * * ?");
7    }
8
9}

MyTask.java & 测试类，将配置在xml中的代码抽离出来

 1public class MyTask {
 2
 3    public static void main(String[] args) throws Exception {
 4
 5        DemoTask demoTask = new DemoTask();
 6
 7        // 定义了；执行的内容
 8        MethodInvokingJobDetailFactoryBean methodInvokingJobDetailFactoryBean = new MethodInvokingJobDetailFactoryBean();
 9        methodInvokingJobDetailFactoryBean.setTargetObject(demoTask);
10        methodInvokingJobDetailFactoryBean.setTargetMethod("execute");
11        methodInvokingJobDetailFactoryBean.setConcurrent(true);
12        methodInvokingJobDetailFactoryBean.setName("demoTask");
13        methodInvokingJobDetailFactoryBean.afterPropertiesSet();
14
15        // 定义了；执行的计划
16        CronTriggerFactoryBean cronTriggerFactoryBean = new CronTriggerFactoryBean();
17        cronTriggerFactoryBean.setJobDetail(methodInvokingJobDetailFactoryBean.getObject());
18        cronTriggerFactoryBean.setCron_Expression("0/5 * * * * ?");
19        cronTriggerFactoryBean.setName("demoTask");
20        cronTriggerFactoryBean.afterPropertiesSet();
21
22        // 实现了；执行的功能
23        SchedulerFactoryBean schedulerFactoryBean = new SchedulerFactoryBean();
24        schedulerFactoryBean.setTriggers(cronTriggerFactoryBean.getObject());
25        schedulerFactoryBean.setAutoStartup(true);
26        schedulerFactoryBean.afterPropertiesSet();
27
28        schedulerFactoryBean.start();
29
30        // 暂停住
31        System.in.read();
32
33    }
34
35}

如果一切顺利，那么会有如下结果：

 12020-01-04 10:47:16.369 [main] INFO  org.quartz.impl.StdSchedulerFactory[1220] - Using default implementation for ThreadExecutor
 22020-01-04 10:47:16.421 [main] INFO  org.quartz.core.SchedulerSignalerImpl[61] - Initialized Scheduler Signaller of type: class org.quartz.core.SchedulerSignalerImpl
 32020-01-04 10:47:16.422 [main] INFO  org.quartz.core.QuartzScheduler[229] - Quartz Scheduler v.2.3.2 created.
 42020-01-04 10:47:16.423 [main] INFO  org.quartz.simpl.RAMJobStore[155] - RAMJobStore initialized.
 52020-01-04 10:47:16.424 [main] INFO  org.quartz.core.QuartzScheduler[294] - Scheduler meta-data: Quartz Scheduler (v2.3.2) 'QuartzScheduler' with instanceId 'NON_CLUSTERED'
 6  Scheduler class: 'org.quartz.core.QuartzScheduler' - running locally.
 7  NOT STARTED.
 8  Currently in standby mode.
 9  Number of jobs executed: 0
10  Using thread pool 'org.quartz.simpl.SimpleThreadPool' - with 10 threads.
11  Using job-store 'org.quartz.simpl.RAMJobStore' - which does not support persistence. and is not clustered.
12
132020-01-04 10:47:16.424 [main] INFO  org.quartz.impl.StdSchedulerFactory[1374] - Quartz scheduler 'QuartzScheduler' initialized from an externally provided properties instance.
142020-01-04 10:47:16.424 [main] INFO  org.quartz.impl.StdSchedulerFactory[1378] - Quartz scheduler version: 2.3.2
152020-01-04 10:47:16.426 [main] INFO  org.quartz.core.QuartzScheduler[2293] - JobFactory set to: org.springframework.scheduling.quartz.AdaptableJobFactory@3e9b1010
162020-01-04 10:47:16.651 [main] INFO  org.quartz.core.QuartzScheduler[547] - Scheduler QuartzScheduler_$_NON_CLUSTERED started.
17一月 04, 2020 10:47:16 上午 org.springframework.scheduling.quartz.SchedulerFactoryBean startScheduler
18信息: Starting Quartz Scheduler now
192020-01-04 10:47:20.321 [QuartzScheduler_Worker-1] INFO  org.itstack.demo.DemoTask[11] - 定时处理用户信息任务：0/5 * * * * ?
202020-01-04 10:47:25.001 [QuartzScheduler_Worker-2] INFO  org.itstack.demo.DemoTask[11] - 定时处理用户信息任务：0/5 * * * * ?
212020-01-04 10:47:30.000 [QuartzScheduler_Worker-3] INFO  org.itstack.demo.DemoTask[11] - 定时处理用户信息任务：0/5 * * * * ?
222020-01-04 10:47:35.001 [QuartzScheduler_Worker-4] INFO  org.itstack.demo.DemoTask[11] - 定时处理用户信息任务：0/5 * * * * ?
232020-01-04 10:47:40.000 [QuartzScheduler_Worker-5] INFO  org.itstack.demo.DemoTask[11] - 定时处理用户信息任务：0/5 * * * * ?
24
25Process finished with exit code -1
26

2. 定义执行内容(MethodInvokingJobDetailFactoryBean)

1// 定义了；执行的内容
2MethodInvokingJobDetailFactoryBean methodInvokingJobDetailFactoryBean = new MethodInvokingJobDetailFactoryBean();
3methodInvokingJobDetailFactoryBean.setTargetObject(demoTask);
4methodInvokingJobDetailFactoryBean.setTargetMethod("execute");
5methodInvokingJobDetailFactoryBean.setConcurrent(true);
6methodInvokingJobDetailFactoryBean.setName("demoTask");
7methodInvokingJobDetailFactoryBean.afterPropertiesSet();

这块内容主要将我们的任务体(即待执行任务DemoTask)交给MethodInvokingJobDetailFactoryBean管理，首先设置必要信息；

• targetObject：目标对象bean，也就是demoTask

• targetMethod：目标方法name，也就是execute

• concurrent：是否并行执行，非并行执行任务，如果上一个任务没有执行完，下一刻不会执行

• name：xml配置非必传，源码中可以获取beanName

最后我们通过手动调用 afterPropertiesSet() 来模拟初始化。如果我们的类是交给 Spring 管理的，那么在实现了 InitializingBean 接口的类，在类配置信息加载后会自动执行 afterPropertiesSet() 。一般实现了 InitializingBean 接口的类，同时也会去实现 FactoryBean 接口，因为这个接口实现后就可以通过 T getObject() 获取自己自定义初始化的类。这也常常用在一些框架开发中。

MethodInvokingJobDetailFactoryBean.afterPropertiesSet()

 1public void afterPropertiesSet() throws ClassNotFoundException, NoSuchMethodException {
 2    prepare();
 3    // Use specific name if given, else fall back to bean name.
 4    String name = (this.name != null ? this.name : this.beanName);
 5    // Consider the concurrent flag to choose between stateful and stateless job.
 6    Class jobClass = (this.concurrent ? MethodInvokingJob.class : StatefulMethodInvokingJob.class);
 7    // Build JobDetail instance.
 8    JobDetailImpl jdi = new JobDetailImpl();
 9    jdi.setName(name);
10    jdi.setGroup(this.group);
11    jdi.setJobClass((Class) jobClass);
12    jdi.setDurability(true);
13    jdi.getJobDataMap().put("methodInvoker", this);
14    this.jobDetail = jdi;
15
16    postProcessJobDetail(this.jobDetail);
17}

• 源码168行： 根据是否并行执行选择任务类，这两个类都是MethodInvokingJobDetailFactoryBean的内部类，非并行执行的StatefulMethodInvokingJob只是继承MethodInvokingJob添加了标记注解。

• 源码171行： 创建JobDetailImpl，添加任务明细信息，注意这类的jdi.setJobClass((Class) jobClass)实际就是MethodInvokingJob。MethodInvokingJob也是我们最终要反射调用执行的内容。

• 源码177行： 初始化任务后赋值给this.jobDetail = jdi，也就是最终的类对象

  MethodInvokingJobDetailFactoryBean.getObject()

  1@Override
  2public JobDetail getObject() {
  3    return this.jobDetail;
  4}
  

• 源码：220行： 获取对象时返回 this.jobDetail，这也就解释了为什么 MethodInvokingJobDetailFactoryBean 初始化后直接赋值给了一个 JobDetail ；

3. 定义执行计划(CronTriggerFactoryBeann)

1// 定义了；执行的计划
2CronTriggerFactoryBean cronTriggerFactoryBean = new CronTriggerFactoryBean();
3cronTriggerFactoryBean.setJobDetail(methodInvokingJobDetailFactoryBean.getObject());
4cronTriggerFactoryBean.setCron_Expression("0/5 * * * * ?");
5cronTriggerFactoryBean.setName("demoTask");
6cronTriggerFactoryBean.afterPropertiesSet();

这一块主要定义任务的执行计划，并将任务执行内容交给 CronTriggerFactoryBean 管理，同时设置必要信息；

• jobDetail：设置任务体，xml 中可以直接将对象赋值，硬编码中设置执行的 JobDetail 对象信息。也就是我们上面设置的 JobDetailImpl ，通过 getObject() 获取出来。

• cronExpression：计划表达式；秒、分、时、日、月、周、年

CronTriggerFactoryBean.afterPropertiesSet()

 1@Override
 2public void afterPropertiesSet() throws ParseException {
 3
 4    // ... 校验属性信息
 5
 6    CronTriggerImpl cti = new CronTriggerImpl();
 7    cti.setName(this.name);
 8    cti.setGroup(this.group);
 9    if (this.jobDetail != null) {
10        cti.setJobKey(this.jobDetail.getKey());
11    }
12    cti.setJobDataMap(this.jobDataMap);
13    cti.setStartTime(this.startTime);
14    cti.setCron_Expression(this.cronExpression);
15    cti.setTimeZone(this.timeZone);
16    cti.setCalendarName(this.calendarName);
17    cti.setPriority(this.priority);
18    cti.setMisfireInstruction(this.misfireInstruction);
19    cti.setDescription(this.description);
20    this.cronTrigger = cti;
21}

• 源码237行： 创建触发器 CronTriggerImpl 并设置相关属性信息

• 源码245行： 生成执行计划类 cti.setCron_Expression(this.cronExpression);

  1public void setCron_Expression(String cronExpression) throws ParseException {
  2    TimeZone origTz = getTimeZone();
  3    this.cronEx = new Cron_Expression(cronExpression);
  4    this.cronEx.setTimeZone(origTz);
  5}
  

  CronExpression.java & 解析Cron表达式

   1protected void build_Expression(String expression) throws ParseException {
   2    expressionParsed = true;
   3    try {

      // ... 初始化 TreeSet xxx = new TreeSet<Integer>();
   4
   5    int exprOn = SECOND;
   6    StringTokenizer exprsTok = new StringTokenizer(expression, " \t",
   7            false);
   8
   9    while (exprsTok.hasMoreTokens() && exprOn <= YEAR) {
  10        String expr = exprsTok.nextToken().trim();
  11
  12        // ... 校验DAY_OF_MONTH和DAY_OF_WEEK字段的特殊字符
  13
  14        StringTokenizer vTok = new StringTokenizer(expr, ",");
  15        while (vTok.hasMoreTokens()) {
  16            String v = vTok.nextToken();
  17            storeExpressionVals(0, v, exprOn);
  18        }
  19        exprOn++;
  20    }
  21
  22    // ... 校验DAY_OF_MONTH和DAY_OF_WEEK字段的特殊字符
  23
  24} catch (ParseException pe) {
  25    throw pe;
  26} catch (Exception e) {
  27    throw new ParseException("Illegal cron expression format ("
  28            + e.toString() + ")", 0);
  29}
  30

  }
  

• Cron表达式有7个字段，CronExpression 把7个字段解析为7个 TreeSet 对象。

• 填充TreeSet对象值的时候，表达式都会转换为起始值、结束值和增量的计算模式，然后计算出匹配的值放进TreeSet对象

CronTriggerFactoryBean.getObject()

1@Override
2public CronTrigger getObject() {
3    return this.cronTrigger;
4}

• 源码257行： 获取对象时返回 this.cronTrigger ，也就是 CronTriggerImpl 对象

4. 调度执行计划(SchedulerFactoryBean)

1// 调度了；执行的计划(scheduler)
2SchedulerFactoryBean schedulerFactoryBean = new SchedulerFactoryBean();
3schedulerFactoryBean.setTriggers(cronTriggerFactoryBean.getObject());
4schedulerFactoryBean.setAutoStartup(true);
5schedulerFactoryBean.afterPropertiesSet();
6
7schedulerFactoryBean.start();

这一部分如名字一样调度工厂，相当于一个指挥官，可以从全局做调度，比如监听哪些trigger已经ready、分配线程等等，同样也需要设置必要的属性信息；

• triggers：按需可以设置多个触发器，本文设置了一个 cronTriggerFactoryBean.getObject() 也就是 CronTriggerImpl 对象

• autoStartup：默认是否自动启动任务，默认值为true

这个过程较长包括：调度工厂、线程池、注册任务等等，整体核心加载流程如下；

• 整个加载过程较长，抽取部分核心代码块进行分析，其中包括的类；

• StdScheduler

• StdSchedulerFactory

• SimpleThreadPool

• QuartzScheduler

• QuartzSchedulerThread

• RAMJobStore

• CronTriggerImpl

• CronExpression

SchedulerFactoryBean.afterPropertiesSet()

 1public void afterPropertiesSet() throws Exception {
 2    if (this.dataSource == null && this.nonTransactionalDataSource != null) {
 3        this.dataSource = this.nonTransactionalDataSource;
 4    }
 5    if (this.applicationContext != null && this.resourceLoader == null) {
 6        this.resourceLoader = this.applicationContext;
 7    }
 8    // Initialize the Scheduler instance...
 9    this.scheduler = prepareScheduler(prepareSchedulerFactory());
10    try {
11        registerListeners();
12        registerJobsAndTriggers();
13    }
14    catch (Exception ex) {
15        try {
16            this.scheduler.shutdown(true);
17        }
18        catch (Exception ex2) {
19            logger.debug("Scheduler shutdown exception after registration failure", ex2);
20        }
21        throw ex;
22    }
23}

• 源码474行： 为调度器做准备工作 prepareScheduler(prepareSchedulerFactory()) ，依次执行如下；

  11）初始化threadPool(线程池)：开发者可以通过org.quartz.threadPool.class配置指定使用哪个线程池类，比如SimpleThreadPool。
  22）初始化jobStore(任务存储方式)：开发者可以通过org.quartz.jobStore.class配置指定使用哪个任务存储类，比如RAMJobStore。
  33）初始化dataSource(数据源)：开发者可以通过org.quartz.dataSource配置指定数据源详情，比如哪个数据库、账号、密码等。
  44）初始化其他配置：包括SchedulerPlugins、JobListeners、TriggerListeners等；
  55）初始化threadExecutor(线程执行器)：默认为DefaultThreadExecutor；
  66）创建工作线程：根据配置创建N个工作thread，执行start()启动thread，并将N个thread顺序add进threadPool实例的空闲线程列表availWorkers中；
  77）创建调度器线程：创建QuartzSchedulerThread实例，并通过threadExecutor.execute(实例)启动调度器线程；
  88）创建调度器：创建StdScheduler实例，将上面所有配置和引用组合进实例中，并将实例存入调度器池中
  

1. SchedulerFactoryBean.prepareScheduler(SchedulerFactory schedulerFactory)

2. SchedulerFactoryBean.createScheduler(schedulerFactory, this.schedulerName);

3. SchedulerFactoryBean.createScheduler(SchedulerFactory schedulerFactory, String schedulerName)

4. Scheduler newScheduler = schedulerFactory.getScheduler();

5. StdSchedulerFactory.getScheduler();

6. sched = instantiate(); 包括一系列核心操作；

• 源码477行： 调用父类 SchedulerAccessor.registerJobsAndTriggers() 注册任务和触发器

  1for (Trigger trigger : this.triggers) {
  2    addTriggerToScheduler(trigger);
  3}
  

SchedulerAccessor.addTriggerToScheduler() & SchedulerAccessor 是SchedulerFactoryBean的父类

 1private boolean addTriggerToScheduler(Trigger trigger) throws SchedulerException {
 2    boolean triggerExists = (getScheduler().getTrigger(trigger.getKey()) != null);
 3    if (triggerExists && !this.overwriteExistingJobs) {
 4        return false;
 5    }
 6    // Check if the Trigger is aware of an associated JobDetail.
 7    JobDetail jobDetail = (JobDetail) trigger.getJobDataMap().remove("jobDetail");
 8    if (triggerExists) {
 9        if (jobDetail != null && !this.jobDetails.contains(jobDetail) && addJobToScheduler(jobDetail)) {
10            this.jobDetails.add(jobDetail);
11        }
12        try {
13            getScheduler().rescheduleJob(trigger.getKey(), trigger);
14        }
15        catch (ObjectAlreadyExistsException ex) {
16            if (logger.isDebugEnabled()) {
17                logger.debug("Unexpectedly encountered existing trigger on rescheduling, assumably due to " +
18                        "cluster race condition: " + ex.getMessage() + " - can safely be ignored");
19            }
20        }
21    }
22    else {
23        try {
24            if (jobDetail != null && !this.jobDetails.contains(jobDetail) &&
25                    (this.overwriteExistingJobs || getScheduler().getJobDetail(jobDetail.getKey()) == null)) {
26                getScheduler().scheduleJob(jobDetail, trigger);
27                this.jobDetails.add(jobDetail);
28            }
29            else {
30                getScheduler().scheduleJob(trigger);
31            }
32        }
33        catch (ObjectAlreadyExistsException ex) {
34            if (logger.isDebugEnabled()) {
35                logger.debug("Unexpectedly encountered existing trigger on job scheduling, assumably due to " +
36                        "cluster race condition: " + ex.getMessage() + " - can safely be ignored");
37            }
38            if (this.overwriteExistingJobs) {
39                getScheduler().rescheduleJob(trigger.getKey(), trigger);
40            }
41        }
42    }
43    return true;
44}

• 源码299行： addJobToScheduler(jobDetail) 一直会调用到 RAMJobStore 进行存放任务信息到 HashMap(100)

   1public void storeJob(JobDetail newJob,
   2    boolean replaceExisting) throws ObjectAlreadyExistsException {
   3    JobWrapper jw = new JobWrapper((JobDetail)newJob.clone());
   4    boolean repl = false;
   5    synchronized (lock) {
   6        if (jobsByKey.get(jw.key) != null) {
   7            if (!replaceExisting) {
   8                throw new ObjectAlreadyExistsException(newJob);
   9            }
  10            repl = true;
  11        }
  12        if (!repl) {
  13            // get job group
  14            HashMap grpMap = jobsByGroup.get(newJob.getKey().getGroup());
  15            if (grpMap == null) {
  16                grpMap = new HashMap(100);
  17                jobsByGroup.put(newJob.getKey().getGroup(), grpMap);
  18            }
  19            // add to jobs by group
  20            grpMap.put(newJob.getKey(), jw);
  21            // add to jobs by FQN map
  22            jobsByKey.put(jw.key, jw);
  23        } else {
  24            // update job detail
  25            JobWrapper orig = jobsByKey.get(jw.key);
  26            orig.jobDetail = jw.jobDetail; // already cloned
  27        }
  28    }
  29}
  

• 初始化线程组；

  SimpleThreadPool.initialize() & 这里的count是默认配置中的数量，可以更改

  1 // create the worker threads and start them
  2 Iterator workerThreads = createWorkerThreads(count).iterator();
  3 while(workerThreads.hasNext()) {
  4     WorkerThread wt = workerThreads.next();
  5     wt.start();
  6     availWorkers.add(wt);
  7 }
  

• prepareScheduler

• createScheduler

• schedulerFactory

• StdSchedulerFactory.getScheduler()

• getScheduler()->instantiate()

• 源码1323行： tp.initialize();

5. 启动定时任务

案例中使用硬编码方式调用 schedulerFactoryBean.start() 启动线程服务。线程的协作通过Object sigLock来实现，关于sigLock.wait()方法都在QuartzSchedulerThread的run方法里面，所以sigLock唤醒的是只有线程QuartzSchedulerThread。核心流程如下；

这个启动过程中，核心的代码类，如下；

• StdScheduler

• QuartzScheduler

• QuartzSchedulerThread

• ThreadPool

• RAMJobStore

• CronTriggerImpl

• JobRunShellFactory

QuartzScheduler.start() & 启动

 1public void start() throws SchedulerException {
 2
 3    if (shuttingDown|| closed) {
 4        throw new SchedulerException(
 5                "The Scheduler cannot be restarted after shutdown() has been called.");
 6    }
 7
 8    // QTZ-212 : calling new schedulerStarting() method on the listeners
 9    // right after entering start()
10    notifySchedulerListenersStarting();
11
12    if (initialStart == null) {
13        initialStart = new Date();
14        this.resources.getJobStore().schedulerStarted();            
15        startPlugins();
16    } else {
17        resources.getJobStore().schedulerResumed();
18    }
19
20    // 唤醒线程
21    schedThread.togglePause(false);
22
23    getLog().info(
24            "Scheduler " + resources.getUniqueIdentifier() + " started.");
25
26    notifySchedulerListenersStarted();
27}

QuartzSchedulerThread.run() & 执行过程

 1@Override
 2public void run() {
 3    int acquiresFailed = 0;
 4
 5    // 只有调用了halt()方法，才会退出这个死循环
 6    while (!halted.get()) {
 7        try {
 8
 9            // 一、如果是暂停状态，则循环超时等待1000毫秒
10
11            // wait a bit, if reading from job store is consistently failing (e.g. DB is down or restarting)..
12
13            // 阻塞直到有空闲的线程可用并返回可用的数量
14            int availThreadCount = qsRsrcs.getThreadPool().blockForAvailableThreads();
15            if(availThreadCount > 0) {
16
17                List triggers;
18                long now = System.currentTimeMillis();
19                clearSignaledSchedulingChange();
20
21                try {
22                    // 二、获取acquire状态的Trigger列表，也就是即将执行的任务
23                    triggers = qsRsrcs.getJobStore().acquireNextTriggers(
24                            now + idleWaitTime, Math.min(availThreadCount, qsRsrcs.getMaxBat
25                    acquiresFailed = 0;
26                    if (log.isDebugEnabled())
27                        log.debug("batch acquisition of " + (triggers == null ? 0 : triggers
28                } catch(){//...}
29
30                if (triggers != null && !triggers.isEmpty()) {
31
32                    // 三：获取List第一个Trigger的下次触发时刻
33                    long triggerTime = triggers.get(0).getNextFireTime().getTime();
34
35                    // 四：获取任务触发集合
36                    List res = qsRsrcs.getJobStore().triggersFired(triggers);
37
38                    // 五：设置Triggers为'executing'状态
39                    qsRsrcs.getJobStore().releaseAcquiredTrigger(triggers.get(i));
40
41                    // 六：创建JobRunShell
42                    qsRsrcs.getJobRunShellFactory().createJobRunShell(bndle);
43
44                    // 七：执行Job
45                    qsRsrcs.getThreadPool().runInThread(shell)
46
47                    continue; // while (!halted)
48                }
49            } else { // if(availThreadCount > 0)
50                // should never happen, if threadPool.blockForAvailableThreads() follows con
51                continue; // while (!halted)
52            }
53
54
55        } catch(RuntimeException re) {
56            getLog().error("Runtime error occurred in main trigger firing loop.", re);
57        }
58    }
59
60    qs = null;
61    qsRsrcs = null;
62}

• 源码391行： 创建JobRunShell，JobRunShell实例在initialize()方法就会把包含业务逻辑类的JobDetailImpl设置为它的成员属性，为后面执行业务逻辑代码做准备。执行业务逻辑代码在runInThread(shell)方法里面。

  QuartzSchedulerThread.run() & 部分代码

  1JobRunShell shell = null;
  2try {
  3    shell = qsRsrcs.getJobRunShellFactory().createJobRunShell(bndle);
  4    shell.initialize(qs);
  5} catch (SchedulerException se) {
  6    qsRsrcs.getJobStore().triggeredJobComplete(triggers.get(i), bndle.getJobDetail(), CompletedExecutionInstruction.SET_ALL_JOB_TRIGGERS_ERROR);
  7    continue;
  8}
  

• 源码398行： qsRsrcs.getThreadPool().runInThread(shell)

  SimpleThreadPool.runInThread

   1// 保存所有WorkerThread的集合
   2private List workers;
   3// 空闲的WorkerThread集合
   4private LinkedList availWorkers = new LinkedList();
   5// 任务的WorkerThread集合
   6private LinkedList busyWorkers = new LinkedList();
   7
   8/**
   9 * 维护workers、availWorkers和busyWorkers三个列表数据
  10 * 有任务需要一个线程出来执行：availWorkers.removeFirst();busyWorkers.add()
  11 * 然后调用WorkThread.run(runnable)方法
  12 */
  13public boolean runInThread(Runnable runnable) {
  14    if (runnable == null) {
  15        return false;
  16    }

  synchronized (nextRunnableLock) {
  17
  18    handoffPending = true;
  19
  20    // Wait until a worker thread is available
  21    while ((availWorkers.size() < 1) && !isShutdown) {
  22        try {
  23            nextRunnableLock.wait(500);
  24        } catch (InterruptedException ignore) {
  25        }
  26    }
  27
  28    if (!isShutdown) {
  29        WorkerThread wt = (WorkerThread)availWorkers.removeFirst();
  30        busyWorkers.add(wt);
  31        wt.run(runnable);
  32    } else {
  33        // If the thread pool is going down, execute the Runnable
  34        // within a new additional worker thread (no thread from the pool).
  35
  36        WorkerThread wt = new WorkerThread(this, threadGroup,
  37                "WorkerThread-LastJob", prio, isMakeThreadsDaemons(), runnable);
  38        busyWorkers.add(wt);
  39        workers.add(wt);
  40        wt.start();
  41    }
  42    nextRunnableLock.notifyAll();
  43    handoffPending = false;
  44}
  45
  46return true;
  47

  }
  

• 源码428行： WorkerThread ，是一个内部类，主要是赋值并唤醒lock对象的等待线程队列

  WorkerThread.run(Runnable newRunnable)

  1public void run(Runnable newRunnable) {
  2    synchronized(lock) {
  3        if(runnable != null) {
  4            throw new IllegalStateException("Already running a Runnable!");
  5        }
  6        runnable = newRunnable;
  7        lock.notifyAll();
  8    }
  9}
  

• 源码561行： WorkerThread 的run方法，方法执行lock.notifyAll()后，对应的WorkerThread就会来到run()方法。到这！接近曙光了！终于来到了执行业务的execute()方法的倒数第二步，runnable对象是一个JobRunShell对象，下面在看JobRunShell.run()方法。

  WorkerThread.run()

   1@Override
   2public void run() {
   3    boolean ran = false;

  while (run.get()) {
   4    try {
   5        synchronized(lock) {
   6            while (runnable == null && run.get()) {
   7                lock.wait(500);
   8            }
   9            if (runnable != null) {
  10                ran = true;
  11                // 启动真正执行的内容，runnable就是JobRunShell
  12                runnable.run();
  13            }
  14        }
  15    } cache(){//...}
  16}
  17//if (log.isDebugEnabled())
  18try {
  19    getLog().debug("WorkerThread is shut down.");
  20} catch(Exception e) {
  21    // ignore to help with a tomcat glitch
  22}
  23

  }
  

JobRunShell.run() & 从上面WorkerThread.run()，调用到这里执行

 1public void run() {
 2    qs.addInternalSchedulerListener(this);
 3
 4    try {
 5        OperableTrigger trigger = (OperableTrigger) jec.getTrigger();
 6        JobDetail jobDetail = jec.getJobDetail();
 7
 8        do {
 9            // ...
10
11            long startTime = System.currentTimeMillis();
12            long endTime = startTime;
13
14            // execute the job
15            try {
16                log.debug("Calling execute on job " + jobDetail.getKey());
17
18                // 执行业务代码，也就是我们的task
19                job.execute(jec);
20
21                endTime = System.currentTimeMillis();
22            } catch (JobExecutionException jee) {
23                endTime = System.currentTimeMillis();
24                jobExEx = jee;
25                getLog().info("Job " + jobDetail.getKey() +
26                        " threw a JobExecutionException: ", jobExEx);
27            } catch (Throwable e) {
28                endTime = System.currentTimeMillis();
29                getLog().error("Job " + jobDetail.getKey() +
30                        " threw an unhandled Exception: ", e);
31                SchedulerException se = new SchedulerException(
32                        "Job threw an unhandled exception.", e);
33                qs.notifySchedulerListenersError("Job ("
34                        + jec.getJobDetail().getKey()
35                        + " threw an exception.", se);
36                jobExEx = new JobExecutionException(se, false);
37            }
38
39            jec.setJobRunTime(endTime - startTime);
40
41            // 其他代码
42        } while (true);
43
44    } finally {
45        qs.removeInternalSchedulerListener(this);
46    }
47}

QuartzJobBean.execte() & 继续往下走

 1public final void execute(JobExecutionContext context) throws JobExecutionException {
 2    try {
 3        BeanWrapper bw = PropertyAccessorFactory.forBeanPropertyAccess(this);
 4        MutablePropertyValues pvs = new MutablePropertyValues();
 5        pvs.addPropertyValues(context.getScheduler().getContext());
 6        pvs.addPropertyValues(context.getMergedJobDataMap());
 7        bw.setPropertyValues(pvs, true);
 8    }
 9    catch (SchedulerException ex) {
10        throw new JobExecutionException(ex);
11    }
12    executeInternal(context);
13}

MethodInvokingJobDetailFactoryBean->MethodInvokingJob.executeInternal(JobExecutionContext context)

 1protected void executeInternal(JobExecutionContext context) throws JobExecutionException {
 2    try {
 3        // 反射执行业务代码
 4        context.setResult(this.methodInvoker.invoke());
 5    }
 6    catch (InvocationTargetException ex) {
 7        if (ex.getTargetException() instanceof JobExecutionException) {
 8            // -> JobExecutionException, to be logged at info level by Quartz
 9            throw (JobExecutionException) ex.getTargetException();
10        }
11        else {
12            // -> "unhandled exception", to be logged at error level by Quartz
13            throw new JobMethodInvocationFailedException(this.methodInvoker, ex.getTargetException());
14        }
15    }
16    catch (Exception ex) {
17        // -> "unhandled exception", to be logged at error level by Quartz
18        throw new JobMethodInvocationFailedException(this.methodInvoker, ex);
19    }
20}

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