带有调度程序的简单Spring Batch作业：第一次迭代成功。后续迭代失败

我通过STS提供的Simple Spring Batch Project尝试了Spring Batch 。我添加了Spring的调度功能，并使用PostgreSQL来存储元数据。

我使用一个简单的配置以及ItemReader和ItemWriter的示例实现，如下所示。作业定义为每15秒运行一次。尽管在第一次迭代中一切正常，但在后续迭代中似乎跳过了读写操作。

这是作业配置：

<batch:job id="job1">
    <batch:step id="step1">
        <batch:tasklet start-limit="100" transaction-manager="transactionManager">
            <batch:chunk reader="reader" writer="writer"
                commit-interval="1" />
        </batch:tasklet>
    </batch:step>
</batch:job>

<!-- Run every 15 seconds -->
<task:scheduled-tasks>
    <task:scheduled ref="testTask" method="run"
        cron="*/15 * * * * *" />
</task:scheduled-tasks>

在这里您可以看到我的读者和作家：

@Component("reader")
public class ExampleItemReader implements ItemReader<String> {

    private String[] input = {"Hello world!","Wow!", "Thats","cool!",null};
    private int index = 0;

    public String read() throws Exception {
        if (index < input.length) {
            return input[index++];
        }
        else {
            return null;
        }
     }
}

@Component("writer")
public class ExampleItemWriter implements ItemWriter<Object> {

     public void write(List<? extends Object> data) throws Exception {
           System.out.println("data: " + data);
     }
}

这是迭代1和2的控制台输出：

<Job: [FlowJob: [name=job1]] launched with the following parameters: [{date=Fri Dec 20 17:00:15 CET 2013}]>
<Job execution starting: JobExecution: id=18, version=0, startTime=null, endTime=null, lastUpdated=Fri Dec 20 17:00:15 CET 2013, status=STARTING, exitStatus=exitCode=UNKNOWN;exitDescription=, job=[JobInstance: id=18, version=0,JobParameters=[{date=Fri Dec 20 17:00:15 CET 2013}], Job=[job1]]>
<Resuming state=job1.step1 with status=UNKNOWN>
<Handling state=job1.step1>
<Executing step: [step1]>
<Executing: id=18>
<Starting repeat context.>
<Repeat operation about to start at count=1>
<Preparing chunk execution for StepContext: org.springframework.batch.core.scope.context.StepContext@33f487e7>
<Chunk execution starting: queue size=0>
<Starting repeat context.>
<Repeat operation about to start at count=1>
<Repeat is complete according to policy and result value.>
<[Hello world!]>
<Inputs not busy, ended: false>
<Applying contribution: [StepContribution: read=1, written=1, filtered=0, readSkips=0, writeSkips=0, processSkips=0, exitStatus=EXECUTING]>
<Saving step execution before commit: StepExecution: id=18, version=1, name=step1, status=STARTED, exitStatus=EXECUTING, readCount=1, filterCount=0, writeCount=1 readSkipCount=0, writeSkipCount=0, processSkipCount=0, commitCount=1, rollbackCount=0, exitDescription=>


... output of other chunks ommitted ...


<Repeat is complete according to policy and result value.>
<Step execution success: id=18>
<Step execution complete: StepExecution: id=18, version=7, name=step1, status=COMPLETED, exitStatus=COMPLETED, readCount=4, filterCount=0, writeCount=4 readSkipCount=0, writeSkipCount=0, processSkipCount=0, commitCount=5, rollbackCount=0>
<Completed state=job1.step1 with status=COMPLETED>
<Handling state=job1.end1>
<Completed state=job1.end1 with status=COMPLETED>
<Job execution complete: JobExecution: id=18, version=1, startTime=Fri Dec 20 17:00:15 CET 2013, endTime=null, lastUpdated=Fri Dec 20 17:00:15 CET 2013, status=COMPLETED, exitStatus=exitCode=COMPLETED;exitDescription=, job=[JobInstance: id=18, version=0, JobParameters=[{date=Fri Dec 20 17:00:15 CET 2013}], Job=[job1]]>
<Job: [FlowJob: [name=job1]] completed with the following parameters: [{date=Fri Dec 20 17:00:15 CET 2013}] and the following status: [COMPLETED]>
Exit Status : COMPLETED

到目前为止，我不知道是什么会导致这种行为。我希望你们中的每个人都能告诉我该怎么做，以使阅读和写作可以在任何迭代中进行！

先感谢您！

痛手指