如何中断正在执行IO的 Quartz 作业
Interrupt a Quartz job that doing IO
如果你想中断正在执行IO的 Quartz 作业，在你使用 InterruptibleChannel 时这是可行的。引用一下Oracle链接：实现了这个接口的通道，是可中断的：如果一个线程在一个中断通道阻塞I/O操作，另一个线程能调用阻塞的线程的中断方法。这将导致的通道被关闭，被阻塞的线程收到一个ClosedByInterruptException，设置被阻塞的线程的中断状态。因此，获得自己工作的执行线程的作业计划，能保存供以后使用。当Quartz调度中断作业，你可以再调用该线程的interrupt（）方法来停止读/写操作。这里有一个简单的例子：
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package demo;
// import statements excluded for brevity
public class MyJob implements InterruptableJob {
private static Logger LOG = LoggerFactory.getLogger(MyJob.class);
private volatile boolean isJobInterrupted = false;
private JobKey jobKey = null;
private volatile Thread thisThread;
public MyJob() {
}
public void execute(JobExecutionContext context) throws JobExecutionException {
thisThread = Thread.currentThread();
LOG.info("Thread name of the current job: " + thisThread.getName());
jobKey = context.getJobDetail().getKey();
LOG.info("Job " + jobKey + " executing at " + new Date());
try {
String fileUrl = "http://d2zwv9pap9ylyd.cloudfront.net/terracotta-3.6.1.tar.gz"; // 59 MB
String localFile = "terracotta-3.6.1.tar.gz";
download(fileUrl, localFile);
} catch (ClosedByInterruptException e) {
LOG.info("Caught ClosedByInterruptException... exiting job.");
} catch (IOException e) {
LOG.info("Caught IOException... exiting job.", e);
} finally {
if (isJobInterrupted) {
LOG.info("Job " + jobKey + " did not complete");
} else {
LOG.info("Job " + jobKey + " completed at " + new Date());
}
}
}
// this method is called by the scheduler
public void interrupt() throws UnableToInterruptJobException {
LOG.info("Job " + jobKey + " -- INTERRUPTING --");
isJobInterrupted = true;
if (thisThread != null) {
// this called cause the ClosedByInterruptException to happen
thisThread.interrupt();
}
}
private void download(String address, String localFileName) throws ClosedByInterruptException, IOException {
URL url = new URL(address);
ReadableByteChannel src = Channels.newChannel(url.openStream());
WritableByteChannel dest = new FileOutputStream(new File(localFileName)).getChannel();
try {
System.out.println("Downloading " + address + " to " + new File(localFileName).getCanonicalPath());
int size = fastChannelCopy(src, dest);
System.out.println("Download completed! " + (size / 1024 / 1024) + " MB");
} finally {
src.close();
dest.close();
}
}
// Code copied from http://thomaswabner.wordpress.com/2007/10/09/fast-stream-copy-using-javanio-channels/
private static int fastChannelCopy(final ReadableByteChannel src, final WritableByteChannel dest) throws IOException {
final ByteBuffer buffer = ByteBuffer.allocateDirect(16 * 1024);
int count = 0;
int total = 0;
while ((count = src.read(buffer)) != -1) {
total += count;
// prepare the buffer to be drained
buffer.flip();
// write to the channel, may block
dest.write(buffer);
// If partial transfer, shift remainder down
// If buffer is empty, same as doing clear()
buffer.compact();
}
// EOF will leave buffer in fill state
buffer.flip();
// make sure the buffer is fully drained.
while (buffer.hasRemaining()) {
dest.write(buffer);
}
return total;
}
}
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这是我的主类，创建Quartz Scheduler和模拟预期的中断。下载将需要大约40秒完成（59MB文件）。为了看到我们的作业确实是在下载过程中中断，我们启动调度然后休息5秒。注：如果您想看到的作业完成，休息了约40秒。
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package demo;
import static org.quartz.DateBuilder.nextGivenSecondDate;
import static org.quartz.JobBuilder.newJob;
import static org.quartz.SimpleScheduleBuilder.simpleSchedule;
import static org.quartz.TriggerBuilder.newTrigger;
// other imports excluded for brevity
public class InterruptExample {
public void run() throws Exception {
final Logger log = LoggerFactory.getLogger(InterruptExample.class);
log.info("------- Initializing ----------------------");
// First we must get a reference to a scheduler
SchedulerFactory sf = new StdSchedulerFactory();
Scheduler sched = sf.getScheduler();
log.info("------- Initialization Complete -----------");
log.info("------- Scheduling Jobs -------------------");
// get a "nice round" time a few seconds in the future...
Date startTime = nextGivenSecondDate(null, 1);
JobDetail job = newJob(MyJob.class).withIdentity("myJob", "group1").build();
SimpleTrigger trigger = newTrigger().withIdentity("trigger1", "group1").startAt(startTime)
.withSchedule(simpleSchedule()).build();
sched.scheduleJob(job, trigger);
// start up the scheduler (jobs do not start to fire until
// the scheduler has been started)
sched.start();
log.info("Scheduler thread's name: " + Thread.currentThread().getName());
log.info("------- Started Scheduler -----------------");
try {
// if you want to see the job to finish successfully, sleep for about 40 seconds
Thread.sleep(5 * 1000L);
// tell the scheduler to interrupt our job
sched.interrupt(job.getKey());
Thread.sleep(3 * 1000L);
} catch (Exception e) {
e.printStackTrace();
}
log.info("------- Shutting Down ---------------------");
sched.shutdown(true);
log.info("------- Shutdown Complete -----------------");
}
public static void main(String[] args) throws Exception {
InterruptExample example = new InterruptExample();
example.run();
}
}
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这是日志，说明我们的作业被intterupted提早退出
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INFO [main] ------- Initializing ----------------------
INFO [main] Using default implementation for ThreadExecutor
INFO [main] Job execution threads will use class loader of thread: main
INFO [main] Initialized Scheduler Signaller of type: class org.quartz.core.SchedulerSignalerImpl
INFO [main] Quartz Scheduler v.2.1.3 created.
INFO [main] RAMJobStore initialized.
INFO [main] Scheduler meta-data: Quartz Scheduler (v2.1.3) 'DefaultQuartzScheduler' with instanceId 'NON_CLUSTERED'
Scheduler class: 'org.quartz.core.QuartzScheduler' - running locally.
NOT STARTED.
Currently in standby mode.
Number of jobs executed: 0
Using thread pool 'org.quartz.simpl.SimpleThreadPool' - with 10 threads.
Using job-store 'org.quartz.simpl.RAMJobStore' - which does not support persistence. and is not clustered.
INFO [main] Quartz scheduler 'DefaultQuartzScheduler' initialized from default resource file in Quartz package: 'quartz.properties'
INFO [main] Quartz scheduler version: 2.1.3
INFO [main] ------- Initialization Complete -----------
INFO [main] ------- Scheduling Jobs -------------------
INFO [main] Scheduler DefaultQuartzScheduler_$_NON_CLUSTERED started.
INFO [main] Scheduler thread's name: main
INFO [main] ------- Started Scheduler -----------------
INFO [DefaultQuartzScheduler_Worker-1] Thread name of the current job: DefaultQuartzScheduler_Worker-1
NFO [DefaultQuartzScheduler_Worker-1] Job group1.myJob executing at Mon Apr 16 16:24:40 PDT 2012
Downloading http://d2zwv9pap9ylyd.cloudfront.net/terracotta-3.6.1.tar.gz to S:\quartz-interrupt-demo\terracotta-3.6.1.tar.gz
INFO [main] Job group1.myJob -- INTERRUPTING --
INFO [DefaultQuartzScheduler_Worker-1] Caught ClosedByInterruptException... exiting job.
INFO [DefaultQuartzScheduler_Worker-1] Job group1.myJob did not complete
ERROR [DefaultQuartzScheduler_Worker-1] Worker thread was interrupt()'ed.
java.lang.InterruptedException
at java.lang.Object.wait(Native Method)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:552)
INFO [main] ------- Shutting Down ---------------------
INFO [main] Scheduler DefaultQuartzScheduler_$_NON_CLUSTERED shutting down.
INFO [main] Scheduler DefaultQuartzScheduler_$_NON_CLUSTERED paused.
INFO [main] Scheduler DefaultQuartzScheduler_$_NON_CLUSTERED shutdown complete.
INFO [main] ------- Shutdown Complete -----------------
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整个例子可以在这里下载