重新启动quartz调度程序而不出错

Question

语境

我试图使用JDBC在集群模式下使用quartz调度器。

问题

在开始使用集群模式下的jdbc之前，我只是用RAM存储测试了调度器。这没有问题，我能够重新启动调度程序（主类）没有任何错误。我现在遇到的问题是，当我停止执行(CTRL+C)然后重新启动它时，我总是得到错误消息：

org.quartz.ObjectAlreadyExistsException: Unable to store Job : 'MyTestJob', because one already exists with this identification.

我不明白这是怎么回事。quartz不支持重新启动调度程序吗？我的意思是，如果出现崩溃，调度程序在恢复后重新启动会发生什么？从quartz数据库中删除作业是唯一的选择吗？也许还有另一种方法或什么我错过了。我觉得使用一个不能处理重启的库不太舒服。

下面是我的配置：

#============================================================================
# Configure Main Scheduler Properties  
#============================================================================

org.quartz.scheduler.skipUpdateCheck = true
org.quartz.scheduler.instanceName = Test-Scheduler
org.quartz.scheduler.instanceId = AUTO

#============================================================================
# Configure ThreadPool  
#============================================================================

org.quartz.threadPool.class = org.quartz.simpl.SimpleThreadPool
org.quartz.threadPool.threadCount = 25
org.quartz.threadPool.threadPriority = 5

#============================================================================
# Configure JobStore  
#============================================================================

org.quartz.jobStore.misfireThreshold = 60000

org.quartz.jobStore.class = org.quartz.impl.jdbcjobstore.JobStoreTX
org.quartz.jobStore.driverDelegateClass = org.quartz.impl.jdbcjobstore.StdJDBCDelegate
org.quartz.jobStore.useProperties = true
org.quartz.jobStore.dataSource = quartzDS
org.quartz.jobStore.tablePrefix = QRTZ_

org.quartz.jobStore.isClustered = true
org.quartz.jobStore.clusterCheckinInterval = 20000

下面是我的代码：

    SchedulerFactory sf = new StdSchedulerFactory();
    Scheduler scheduler = sf.getScheduler();

    scheduler.start();

                JobDetail jobDetail = newJob(job.getClass())
                    .withIdentity("test-name", "test-group")
                    .build();

                CronTrigger trigger = newTrigger()
                    .withIdentity("test-name-trigger", "test-group")
                    .withSchedule(cronSchedule("0 0/1 * * * ?"))
                    .build();

                scheduler.scheduleJob(jobDetail, trigger);

                System.out.println(trigger.getNextFireTime());

编辑

19:57:29,913  INFO StdSchedulerFactory:1184 - Using default implementation for ThreadExecutor
19:57:29,936  INFO SchedulerSignalerImpl:61 - Initialized Scheduler Signaller of type: class org.quartz.core.SchedulerSignalerImpl
19:57:29,936  INFO QuartzScheduler:240 - Quartz Scheduler v.2.2.1 created.
19:57:29,938  INFO JobStoreTX:667 - Using db table-based data access locking (synchronization).
19:57:29,940  INFO JobStoreTX:59 - JobStoreTX initialized.
19:57:29,941  INFO QuartzScheduler:305 - Scheduler meta-data: Quartz Scheduler (v2.2.1) 'Test-Scheduler' with instanceId 'Michael-PC1405447049916'
  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 25 threads.
  Using job-store 'org.quartz.impl.jdbcjobstore.JobStoreTX' - which supports persistence. and is clustered.

19:57:29,941  INFO StdSchedulerFactory:1339 - Quartz scheduler 'Test-Scheduler' initialized from default resource file in Quartz package: 'quartz.properties'
19:57:29,941  INFO StdSchedulerFactory:1343 - Quartz scheduler version: 2.2.1
19:57:29,995  INFO AbstractPoolBackedDataSource:462 - Initializing c3p0 pool... com.mchange.v2.c3p0.ComboPooledDataSource [ acquireIncrement -> 3, acquireRetryAttempts -> 30, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAcquireFailure -> false, checkoutTimeout -> 0, connectionCustomizerClassName -> null, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, dataSourceName -> 1hgeby993gf1xpdmdc44s|7ec4d0, debugUnreturnedConnectionStackTraces -> false, description -> null, driverClass -> com.mysql.jdbc.Driver, factoryClassLocation -> null, forceIgnoreUnresolvedTransactions -> false, identityToken -> 1hgeby993gf1xpdmdc44s|7ec4d0, idleConnectionTestPeriod -> 50, initialPoolSize -> 3, jdbcUrl -> jdbc:mysql://localhost:3306/scheduler, maxAdministrativeTaskTime -> 0, maxConnectionAge -> 0, maxIdleTime -> 0, maxIdleTimeExcessConnections -> 0, maxPoolSize -> 5, maxStatements -> 0, maxStatementsPerConnection -> 120, minPoolSize -> 1, numHelperThreads -> 3, numThreadsAwaitingCheckoutDefaultUser -> 0, preferredTestQuery -> SELECT 1 FROM QRTZ_JOB_DETAILS, properties -> {user=******, password=******}, propertyCycle -> 0, testConnectionOnCheckin -> true, testConnectionOnCheckout -> false, unreturnedConnectionTimeout -> 0, usesTraditionalReflectiveProxies -> false ]
19:57:30,243 DEBUG StdRowLockSemaphore:107 - Lock 'TRIGGER_ACCESS' is desired by: main
19:57:30,262 DEBUG StdRowLockSemaphore:92 - Lock 'TRIGGER_ACCESS' is being obtained: main
19:58:21,328 DEBUG StdRowLockSemaphore:141 - Lock 'TRIGGER_ACCESS' was not obtained by: main - will try again.
19:58:22,329 DEBUG StdRowLockSemaphore:92 - Lock 'TRIGGER_ACCESS' is being obtained: main
19:59:13,389 DEBUG StdRowLockSemaphore:141 - Lock 'TRIGGER_ACCESS' was not obtained by: main - will try again.
19:59:14,389 DEBUG StdRowLockSemaphore:92 - Lock 'TRIGGER_ACCESS' is being obtained: main

Exception in thread "main" org.quartz.impl.jdbcjobstore.LockException: Failure obtaining db row lock: Lock wait timeout exceeded; try restarting transaction [See nested exception: java.sql.SQLException: Lock wait timeout exceeded; try restarting transaction]
    at org.quartz.impl.jdbcjobstore.StdRowLockSemaphore.executeSQL(StdRowLockSemaphore.java:157)
    at org.quartz.impl.jdbcjobstore.DBSemaphore.obtainLock(DBSemaphore.java:113)
    at org.quartz.impl.jdbcjobstore.JobStoreSupport.executeInNonManagedTXLock(JobStoreSupport.java:3780)
    at org.quartz.impl.jdbcjobstore.JobStoreTX.executeInLock(JobStoreTX.java:93)
    at org.quartz.impl.jdbcjobstore.JobStoreSupport.clearAllSchedulingData(JobStoreSupport.java:1956)
    at org.quartz.core.QuartzScheduler.clear(QuartzScheduler.java:1572)
    at org.quartz.impl.StdScheduler.clear(StdScheduler.java:239)
    at com.scs.core.cron.TaskRunner.main(TaskRunner.java:52)

  20:04:15,993 DEBUG SimpleSemaphore:132 - Lock 'TRIGGER_ACCESS' retuned by: main
  20:04:15,993 DEBUG JobStoreTX:703 - JobStore background threads started (as scheduler was started).
  20:04:15,994  INFO QuartzScheduler:575 - Scheduler Test-Scheduler_$_NON_CLUSTERED started.
  20:04:15,994 DEBUG JobStoreTX:3933 - MisfireHandler: scanning for misfires...
  20:04:16,000 DEBUG JobStoreTX:3182 - Found 0 triggers that missed their scheduled fire-time.
  20:04:16,004 DEBUG QuartzSchedulerThread:276 - batch acquisition of 0 triggers
  20:04:16,008 DEBUG SimpleSemaphore:81 - Lock 'TRIGGER_ACCESS' is desired by: main
  20:04:16,008 DEBUG SimpleSemaphore:88 - Lock 'TRIGGER_ACCESS' is being obtained: main
  20:04:16,008 DEBUG SimpleSemaphore:105 - Lock 'TRIGGER_ACCESS' given to: main
        20:04:16,052 DEBUG SimpleSemaphore:132 - Lock 'TRIGGER_ACCESS' retuned by: main
        Found job: class to.test.cron.ImportProducts
        Tue Jul 15 20:05:00 CEST 2014
        isStarted=true
        isShutdown=false
        isInStandbyMode=false
        20:04:16,058 DEBUG QuartzSchedulerThread:276 - batch acquisition of 0 triggers
        20:04:42,961 ERROR ErrorLogger:2425 - An error occurred while scanning for the next triggers to fire.
        org.quartz.JobPersistenceException: Couldn't acquire next trigger: to.test.cron.ImportProducts [See nested exception: java.lang.ClassNotFoundException: to.test.cron.ImportProducts]
            at org.quartz.impl.jdbcjobstore.JobStoreSupport.acquireNextTrigger(JobStoreSupport.java:2848)
            at org.quartz.impl.jdbcjobstore.JobStoreSupport$40.execute(JobStoreSupport.java:2759)
            at org.quartz.impl.jdbcjobstore.JobStoreSupport$40.execute(JobStoreSupport.java:2757)
            at org.quartz.impl.jdbcjobstore.JobStoreSupport.executeInNonManagedTXLock(JobStoreSupport.java:3787)
            at org.quartz.impl.jdbcjobstore.JobStoreSupport.acquireNextTriggers(JobStoreSupport.java:2756)
            at org.quartz.core.QuartzSchedulerThread.run(QuartzSchedulerThread.java:272)
        Caused by: java.lang.ClassNotFoundException: to.test.cron.ImportProducts
            at java.net.URLClassLoader$1.run(Unknown Source)
            at java.net.URLClassLoader$1.run(Unknown Source)
            at java.security.AccessController.doPrivileged(Native Method)
            at java.net.URLClassLoader.findClass(Unknown Source)
            at java.lang.ClassLoader.loadClass(Unknown Source)
            at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
            at java.lang.ClassLoader.loadClass(Unknown Source)
            at org.quartz.simpl.InitThreadContextClassLoadHelper.loadClass(InitThreadContextClassLoadHelper.java:72)
            at org.quartz.simpl.CascadingClassLoadHelper.loadClass(CascadingClassLoadHelper.java:114)
            at org.quartz.simpl.CascadingClassLoadHelper.loadClass(CascadingClassLoadHelper.java:138)
            at org.quartz.impl.jdbcjobstore.StdJDBCDelegate.selectJobDetail(StdJDBCDelegate.java:852)
            at org.quartz.impl.jdbcjobstore.JobStoreSupport.acquireNextTrigger(JobStoreSupport.java:2816)
            ... 5 more

我不太明白为什么我在三种不同的模式中得到了三种完全不同的行为。Surley如果类可以在RAM模式下找到，为什么不能在jdbc模式下找到呢？为什么不以集群模式记录？这个类实际上是在一个OSGi类型的模块中。这会导致问题吗（在JDBC模式下）？有什么我可以做的，这样可以找到类，像传递类加载器等到石英？

我现在很迷路，真的很感激任何帮助。如果不得不回到标准的cron工作岗位，那将是一种耻辱，尤其是在quartz有这么多东西可以提供的情况下。

提前感谢您提供的任何帮助，

Answer 1

这是持久化作业存储的一般“问题”。您的应用程序显然试图添加一个已经存在于作业存储区中的作业，因为它已经由您的应用程序在过去添加过。您有两种选择：

>

在尝试添加作业/触发器之前，在应用程序初始化期间清除作业存储区的内容。从Quartz2.x开始，您可以使用一个新方法scheduler.clear（）。

您可以修改应用程序代码，以处理您试图添加的作业/触发器可能已经存在于作业存储区中的事实。如果存在，则只需在必要时更新作业/触发器，或者完全跳过作业/触发器。

希望这能有所帮助。