Spring Batch 在流程中有两个步骤。为啥第二步永远不会运行，第一步是无限循环
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【中文标题】Spring Batch 在流程中有两个步骤。为啥第二步永远不会运行，第一步是无限循环【英文标题】：Spring Batch with two Steps in flow. Why second step never run and first step is in infinite loopSpring Batch 在流程中有两个步骤。为什么第二步永远不会运行，第一步是无限循环 【发布时间】：2016-04-24 10:27:05 【问题描述】：我的要求：创建一个调度程序来定期调用批处理，并且在批处理内部，我需要两个步骤。 StepA 将开始运行，根据结果，StepB 将调用。 如果您查看控制台日志，您将看到 stepA 被多次调用，比如说，完全相同的时刻。根据@Scheduled(fixedRate=60000) 每分钟应该只有一个电话。我猜这个问题与调度程序没有关系，因为我删除了调度程序并且我遇到了类似的问题。其他相关问题是从未调用过 StepB。我试图创建customDecider（“...next（customDecider（）”）并创建一个私有方法来返回JobExecutionDecider。似乎两者都没有生效。 我最好的猜测是池线程在 StepA 中导致了一些“无限循环”，因为我没有正确设置一些东西，但我没有找到可能是什么。
BatchConfig.java
/*@Bean
public JobExecutionDecider customDecider() throws Exception
return new CustomDecider();
*/
private JobExecutionDecider decider(boolean decision)
return(jobExecution, stepExecution) -> new FlowExecutionStatus(decision ? "OK" : "FAILED");
@Bean
public Job job(Step stepA, Step stepB)
return jobBuilderFactory.get("job1")
//.flow(stepA).on("FAILED").to(stepB).end().build();
.start(stepA)
.next(decider(true))
.on("FAILED")
.stop()
.from(stepA)
.next(stepB)
.build()
.build();
@Bean
public Step stepA(ItemReader<String> readerA, ItemWriter<String> writerA)
return stepBuilderFactory.get("stepA").<String, String> chunk(1)
.reader(readerA)
.writer(writerA)
.allowStartIfComplete(true)
.build();
@Bean
@StepScope
public ItemReader<String> readerA()
return new CustomItemReaderA();
@Bean
public ItemWriter<String> writerA()
return new CustomItemWriterA();
@Bean
public Step stepB(ItemReader<String> readerB, ItemWriter<String> writerB)
return stepBuilderFactory.get("stepB").<String, String> chunk(1)
.reader(readerB)
.writer(writerB)
.allowStartIfComplete(true)
.build();
@Bean
@StepScope
public ItemReader<String> readerB()
return new CustomItemReaderB();
@Bean
public ItemWriter<String> writerB()
return new CustomItemWriterB();
CustomDecider.java
public class CustomDecider implements JobExecutionDecider
@Override
public FlowExecutionStatus decide(JobExecution jobExecution,
StepExecution stepExecution)
return new FlowExecutionStatus("OK");
CustomItemReaderA
public class CustomItemReaderA implements ItemReader<String>
private static final Logger log = LoggerFactory.getLogger(CustomItemReaderA.class);
@Override
public String read() throws Exception, UnexpectedInputException,
ParseException, NonTransientResourceException
log.info("rA");
return "A";
CustomItemWriterA
public class CustomItemWriterA implements ItemWriter<String>
private static final Logger log = LoggerFactory.getLogger(CustomItemWriterA.class);
@Override
public void write(List<? extends String> items) throws Exception
log.info("wA");
CustomItemReaderB 和 CustomItemReaderB 与 Custom...A 相同，只是在 log.info 期间从 A 变为 B 字母并返回
控制台日志
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.488 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.504 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemReaderA : rA
2016-01-18 21:40:37.519 INFO 7340 --- [pool-2-thread-1] com.example.CustomItemWriterA : wA
and so on ...
调度器
@Component
public class QueueScheduler
private static final Logger log = LoggerFactory
.getLogger(QueueScheduler.class);
private Job job;
private JobLauncher jobLauncher;
@Autowired
public QueueScheduler(JobLauncher jobLauncher, @Qualifier("job") Job job)
this.job = job;
this.jobLauncher = jobLauncher;
@Scheduled(fixedRate=60000)
public void runJob()
try
jobLauncher.run(job, new JobParameters());
catch(Exception ex)
log.info(ex.getMessage());
【问题讨论】：
【参考方案1】：问题在于您的CustomItemReaderA。您需要告诉 Reader 何时停止“读取”数据。如果您按照下面给出的修改阅读器，执行将按预期进行。
public class CustomItemReaderA implements ItemReader<String>
private static final Logger log = LoggerFactory
.getLogger(CustomItemReaderA.class);
private int readCount = 0;
@Override
public String read() throws Exception, UnexpectedInputException,
ParseException, NonTransientResourceException
log.info("Inside CustomItemReaderA");
if (readCount == 1)
return null;
readCount++;
return "Read CustomItemReaderA";
【讨论】：
那么，返回 null 是停止 CustomItemReaderA 的唯一方法吗？为了避免重复调用（第二个仅用于返回 null），如果第一次成功，我可以创建一个逻辑以返回 null。如果 ItemReader 的设计考虑到了这样的想法，那么对于这种情况是可以的，但是假设有一个 CustomItemProcessorA 期望从 CustomItemReaderA 读取数据，而 CustomItemWriterA 期望从 CustomItemReaderB 处理数据，则不会返回 null 破坏此类批处理的目的还是强迫我做出一个丑陋的解决方法？还是必须至少阅读两次？ 其他疑问非常接近最后一个：在我的要求中，我必须根据 CustomItemReaderA 决定是否调用 CustomItemReaderB。为此，我知道我必须以某种方式使用 JobExecutionDecider 并通过 ...on(FlowExecutionStatus) 决定它。如何更改 CustomItemReaderA 的状态？好吧，考虑两个选项（失败或成功），我可以使用 return null 表示成功并抛出异常表示失败。但是，让我们考虑三个选项？如何从 CustomItemReaderA 返回三种状态之一？我可以从 CustomItemReaderA 更改 FlowExecutionStatus 吗？以上是关于Spring Batch 在流程中有两个步骤。为啥第二步永远不会运行，第一步是无限循环的主要内容，如果未能解决你的问题，请参考以下文章
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