通过源码分析Java开源任务调度框架Quartz的主要流程
从使用效果、调用链路跟踪、E-R图、循环调度逻辑几个方面分析Quartz。
github项目地址: https://github.com/tanliwei/spring-quartz-cluster-sample , 补充了SQL输出
系统说明:
IDE: IntelliJ
JDK:1.8
Quartz:2.2.1
使用效果
1.从github项目https://github.com/tanliwei/spring-quartz-cluster-sample中,拉取项目到本地,导入IDEA。
相信读者都有一定工作经验,这些细节不赘述。
2.本文采用Mysql数据库。
请执行 resources/scripts/tables_mysql_innodb.sql
3.修改jdbc.properties中数据库配置
4.通过IDEA, Edit Configurations -> Add Tomcat Server, 部署到Tomcat
暴露的Restful 接口 /say-hello.do 以及添加好任务后的调用效果:
添加任务
在tomcat启动成功后,在首页点击“添加任务”,添加如下任务:
代码执行逻辑在SyncJobFactory类中,从Output中可以看到执行的输出信息,
调用链跟踪的最后会回到这个类来。
现在开始跟踪调用链路。
进入方法: Ctrl + 鼠标左键
光标前进/后退: Ctrl + Shirt + 右方向键/左方向键
从配置文件applicationContext.xml配置中找到任务调度核心类SchedulerFactoryBean
resources/applicationContext.xml
<bean id="scheduler" class="org.springframework.scheduling.quartz.SchedulerFactoryBean">
...
</bean>
使用IDEA快捷键,点击进入SchedulerFactoryBean类,它实现了InitializingBean接口,
在Spring中凡是实现了InitializingBean接口的Bean,都会在Bean属性都设置完成后调用afterPropertiesSet()方法.
SchedulerFactoryBean.java
//---------------------------------------------------------------------
// Implementation of InitializingBean interface
// 实现 InitializingBean 接口
//---------------------------------------------------------------------
public void afterPropertiesSet() throws Exception {
//...
// Create SchedulerFactory instance.
// 创建 SchedulerFactory 调度器工厂实例
SchedulerFactory schedulerFactory = (SchedulerFactory)
BeanUtils.instantiateClass(this.schedulerFactoryClass);
initSchedulerFactory(schedulerFactory);
//...
// Get Scheduler instance from SchedulerFactory.
// 通过调度器工厂 获取 调度器实例
try {
this.scheduler = createScheduler(schedulerFactory, this.schedulerName);
//...
}
SchedulerFactoryBean.java
/**
* Create the Scheduler instance for the given factory and scheduler name.
* 通过制定工厂和调度器名称创建调度器实例
* Called by {@link #afterPropertiesSet}.
* <p>The default implementation invokes SchedulerFactory's <code>getScheduler</code>
* method. Can be overridden for custom Scheduler creation.
*/
protected Scheduler createScheduler(SchedulerFactory schedulerFactory, String schedulerName)
throws SchedulerException {
//...
try {
SchedulerRepository repository = SchedulerRepository.getInstance();
synchronized (repository) {
Scheduler existingScheduler = (schedulerName != null ? repository.lookup(schedulerName) : null);
Scheduler newScheduler = schedulerFactory.getScheduler();
if (newScheduler == existingScheduler) {
throw new IllegalStateException("Active Scheduler of name '" + schedulerName + "' already registered " +
"in Quartz SchedulerRepository. Cannot create a new Spring-managed Scheduler of the same name!");
}
//...
}
这个项目走的逻辑是 StdSchedulerFactory.getScheduler()方法,可自行debug。
StdSchedulerFactory.java
/**
* Returns a handle to the Scheduler produced by this factory.
* 返回该工厂创造的调度器的句柄
*/
public Scheduler getScheduler() throws SchedulerException {
if (cfg == null) {
initialize();
} SchedulerRepository schedRep = SchedulerRepository.getInstance(); Scheduler sched = schedRep.lookup(getSchedulerName());
//...
sched = instantiate();
return sched;
}
StdSchedulerFactory.java
private Scheduler instantiate() throws SchedulerException {
//...
//大量的配置初始化、实例化代码
//...
//第1298行代码
qs = new QuartzScheduler(rsrcs, idleWaitTime, dbFailureRetry);
//...
}
QuartzScheduler.java
/**
* Create a <code>QuartzScheduler</code> with the given configuration
* 根据给定的配置 创建Quartz调度器
*/
public QuartzScheduler(QuartzSchedulerResources resources, long idleWaitTime, @Deprecated long dbRetryInterval)
throws SchedulerException {
this.resources = resources;
if (resources.getJobStore() instanceof JobListener) {
addInternalJobListener((JobListener)resources.getJobStore());
}
//private QuartzSchedulerThread schedThread;
this.schedThread = new QuartzSchedulerThread(this, resources);
ThreadExecutor schedThreadExecutor = resources.getThreadExecutor();
//通过线程池执行 Quartz调度器线程
schedThreadExecutor.execute(this.schedThread);
//...
}
QuartzSchedulerThread.java
/**
* <p>
* The main processing loop of the <code>QuartzSchedulerThread</code>.
* Quartz调度器线程的主循环逻辑
* </p>
*/
@Override
public void run() {
//while循环执行,只要调度器为被暂停
while(!halted.get()){
JobRunShell shell = null;
try {
shell = qsRsrcs.getJobRunShellFactory().createJobRunShell(bndle);
shell.initialize(qs);
}
if (qsRsrcs.getThreadPool().runInThread(shell) == false){} }
}
JobRunShell.java
public void run() {
//...
Job job = jec.getJobInstance();
//...
try {
log.debug("Calling execute on job " + jobDetail.getKey());
//执行
job.execute(jec);
endTime = System.currentTimeMillis();
}
//...
//更新Trigger触发器状态,删除FIRED_TRIGGERS触发记录
instCode = trigger.executionComplete(jec, jobExEx);
//...
}
QuartzJobBean.java
/**
* This implementation applies the passed-in job data map as bean property
* values, and delegates to <code>executeInternal</code> afterwards.
* 这个实现 把传入的map数据作为bean属性值,然后委托给 executeInternal 方法
*/
public final void execute(JobExecutionContext context) throws JobExecutionException {
try {
//执行
executeInternal(context);
}
SyncJobFactory.java
//回到了我们的业务类SyncJobFactory的executeInternal方法,
//里面执行我们的业务代码
protected void executeInternal(JobExecutionContext context) throws JobExecutionException {
try {
LOG.info("SyncJobFactory execute" + IPAddressKowalski.getIpAddressAndPort() + " port:"+IPAddressKowalski.getTomcatPort());
}
//...
System.out.println("jobName:" + scheduleJob.getJobName() + " " + scheduleJob);
//...
}
二、E-R图
梳理6张主要的Quartz表:
QRTZ_TRIGGERS 触发器表
SCHED_NAME,调度器名称,集群时为常量值:“ClusterScheduler”。 联合主键,QRTZ_JOB_DETAILS表SCHED_NAME外键
JOB_NAME,任务名。自定义值。 联合主键,QRTZ_JOB_DETAILS表JOB_NAME外键
JOB_GROUP,任务组。 自定义值。联合主键,QRTZ_JOB_DETAILS表JOB_GROUP外键
TRIGGER_STATE,触发器状态: WAITING , ACQUIRED, BLOCKING
NEXT_FIRE_TIME, 下次触发时间:
MISFIRE_INSTR,执行失败后的指令,
非失败策略 MISFIRE_INSTRUCTION_IGNORE_MISFIRE_POLICY = -1;
失败策略 MISFIRE_INSTRUCTION_SMART_POLICY = 0;
TRIGGER_TYPE, 触发器类型,例如CRON,cron表达式类型的触发器
PRIORITY,优先级
QRTZ_CRON_TRIGGERS cron类型触发器表
SCHED_NAME,调度器名称,集群时为常量值:“ClusterScheduler”。 联合主键,QRTZ_TRIGGERS表SCHED_NAME外键
JOB_NAME,任务名。自定义值。 联合主键,QRTZ_TRIGGERS表JOB_NAME外键
JOB_GROUP,任务组。 自定义值。联合主键,QRTZ_TRIGGERS表JOB_GROUP外键
CRON_EXPRESSION, cron表达式, 例如每30秒执行一次, 0/30 * * * * ?
QRTZ_JOB_DETAILS 任务详细表
SCHED_NAME,调度器名称,集群时为常量值:“ClusterScheduler”。联合主键
JOB_NAME,任务名。自定义值。 联合主键
JOB_GROUP,任务组。 自定义值。联合主键
JOB_DATA,blob类型,任务参数
QRTZ_FIRED_TRIGGERS 任务触发表
SCHED_NAME,调度器名称,集群时为常量值:“ClusterScheduler”。联合主键
ENTRY_ID,entry id,联合主键
JOB_NAME,任务名。自定义值。
JOB_GROUP,任务组。 自定义值。
FIRED_TIME, 任务触发时间
STATE,状态
INSTANCE_NAME, 服务器实例名
PRIORITY,优先级
QRTZ_SCHEDULER_STATE
SCHED_NAME,调度器名称,集群时为常量值:“ClusterScheduler”。联合主键
INSTANCE_NAME,服务器实例名。联合主键
LAST_CHECKIN_TIME,上次检查时间
CHECKIN_INTERVAL,检查间隔
QRTZ_LOCKS 全局锁
SCHED_NAME,调度器名称,集群时为常量值:“ClusterScheduler”。联合主键
LOCK_NAME,锁名称,例如,TRIGGER_ACCESS。联合主键
三、循环调度逻辑
主要流程如下:
源码如下:
QuartzSchedulerThread.java
public void run() {
//...
while (!halted.get()) {
try {
//合理休眠
//...
//获取接下来的触发器
//1.状态为WAITING
//2.触发时间在30秒内
//3.不是错过执行的或者错过了但是时间不超过两分钟
triggers = qsRsrcs.getJobStore().acquireNextTriggers(
now + idleWaitTime, Math.min(availThreadCount, qsRsrcs.getMaxBatchSize()), qsRsrcs.getBatchTimeWindow()); //...
//触发任务
List<TriggerFiredResult> res = qsRsrcs.getJobStore().triggersFired(triggers);
//...
JobRunShell shell = null;
//...
//执行代码
if (qsRsrcs.getThreadPool().runInThread(shell) == false) {
//...
} // while (!halted)
//..
}
JobRunShell.java
protected QuartzScheduler qs = null; public void run() {
qs.addInternalSchedulerListener(this);
try {
//...
do {
Job job = jec.getJobInstance();
// execute the job
try {
//执行任务代码
job.execute(jec);
//更新触发器,删除触发记录
qs.notifyJobStoreJobComplete(trigger, jobDetail, instCode);
break;
} while (true);
}
//...
}
四、扩展
除了对主线程 QuartzSchedulerThread 的分析
继续分析JobStoreSupport类的两个线程 ClusterManager 和 MisfireHandler 的分析, 它们维护触发器的MISFIRE_INSTR状态,和调度器状态QRTZ_SCHEDULER_STATE。