Java 已在事务中时启动弹簧批处理作业
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Start a spring batch job when already within a transaction
提问by Hyman
I have simple Spring-Service that (among other tasks) starts a spring batch job with the following code:
我有一个简单的 Spring-Service，它（在其他任务中）使用以下代码启动一个 spring 批处理作业：
@Autowired
private JobRegistry jobRegistry;
@Autowired
private JobLauncher jobLauncher;
public void startMyJob() {
Job job = jobRegistry.getJob("myJobName");
JobParameters jobParameters = new JobParametersBuilder().toJobParameters();
jobLauncher.run(job, jobParameters);
}
This works fine, as long as there is no transaction active when the Serivce-Method is called. However, with an active transaction, I get this exception:
只要在调用 Serivce-Method 时没有活动的事务，就可以正常工作。但是，对于活动事务，我收到此异常：
Caused by: java.lang.IllegalStateException: Existing transaction detected in JobRepository. Please fix this and try again (e.g. remove @Transactional annotations from client).
I cannot easily remove the existing transaction, since it is implied due to some framework code that is not within my reach.
我无法轻松删除现有事务，因为它是由于某些框架代码无法实现而隐含的。
So, how can I start the job anyway within this context? The new job just should not use the existing transaction. It could just start its own transaction - but how to configure it to make it work?
那么，在这种情况下，我怎样才能开始工作呢？新作业不应使用现有事务。它可以只开始自己的事务——但如何配置它以使其工作？
采纳答案by Luca Basso Ricci
Use AbstractJobRepositoryFactoryBean.ValidateTransactionState, but use carefully (Warning: Dragons ahead).
使用AbstractJobRepositoryFactoryBean.ValidateTransactionState，但要小心使用（警告：前方有龙）。
To use another transaction you can inject a custom SimpleJobLauncher.executorwith method Executor.runmarked as @Transactional() (or create a custom JobLauncherand do the same trick on method run).
要使用另一个事务，您可以SimpleJobLauncher.executor使用Executor.run标记为 @Transactional() 的方法注入自定义（或创建自定义JobLauncher并在 method 上执行相同的技巧run）。
I haven't tried because I haven't faced the problem, but hope can help.
我没有尝试过，因为我还没有遇到过这个问题，但希望能有所帮助。
回答by Luca Basso Ricci
I've dealt with this by creating a separate bean AsyncJobLauncher which has a run method with the same signature as JobLauncher and delegates to the real one, but marked with Spring's @Async. So, the launching of the job happened in the background on a new thread, so it was in its own transaction.
我通过创建一个单独的 bean AsyncJobLauncher 来处理这个问题，它有一个与 JobLauncher 具有相同签名的 run 方法，并委托给真正的方法，但用 Spring 的 @Async 标记。因此，作业的启动发生在新线程的后台，因此它在自己的事务中。
回答by Schaka
I had a similar problem. In particular, I was starting my jobs from within a class that was annotated with @Transactional(propagation = Propagation.REQUIRES_NEW). To work around this, I started my jobs from a somewhere, where I had no active transaction. Then I ran into your problem as described above - and here is how I solved it:
我有一个类似的问题。特别是，我是从一个用@Transactional(propagation = Propagation.REQUIRES_NEW). 为了解决这个问题，我从一个没有活动事务的地方开始我的工作。然后我遇到了你的问题，如上所述 - 这是我解决它的方法：
set validateTransactionStateto false on the JobRepository - it now ignored the transactions that were automatically created in the class my ItemProcessorcalled (because said class was annotated with @Transcational, as explained above).
validateTransactionState在 JobRepository 上设置为 false - 它现在忽略在我ItemProcessor调用的类中自动创建的事务（因为所述类用@Transcational 进行了注释，如上所述）。
This made my jobs run just fine. However, I wasn't sure if I was now dealing with 2 open transactions and wanted to be sure I was not. So I also removed the transcational annnotation on the class level and moved it to all public methods, except the ones called by my Itemprocessor. Thus I solved the issue.
这使我的工作运行得很好。但是，我不确定我现在是否正在处理 2 个未结交易，并想确定我不是。所以我也去掉了类级别的transcational注解，把它移到所有公共方法中，除了我的Itemprocessor调用的方法。因此我解决了这个问题。
回答by Corneil du Plessis
My solution was that the method starting the job needed to be annotated with @Transactional(propagation = Propagation.NOT_SUPPORTED)this would suspend the current transaction and resume after execution.
我的解决方案是，启动作业的方法需要用@Transactional(propagation = Propagation.NOT_SUPPORTED)this进行注释，这将挂起当前事务并在执行后恢复。
You can set transactionAttributeon your readers and writers if you need anything different from defaults.
transactionAttribute如果您需要与默认值不同的任何内容，您可以设置您的读者和作者。
I did not need setValidateTransactionState(false)on the JobRepositoryFactoryBeanor JobRepository
我不需要setValidateTransactionState(false)在JobRepositoryFactoryBean或JobRepository
