InvalidDataAccessResourceUsageException：意外的光标位置更改

Question

在 Spring Batch 应用程序中尝试从数据库读取时遇到以下异常。任何见解都会有所帮助。这是在使用 JdbcCursorItemReader 时引起的。该应用程序使用 JdbcPagingItemReader 可以正常工作。

使用 JdbcCursorItemReader 时是否还需要明确关闭任何资源（游标等）？如果是这样，我们该怎么做？

SEVERE: Encountered an error executing the step
    org.springframework.dao.InvalidDataAccessResourceUsageException: Unexpected cursor position change.
        at org.springframework.batch.item.database.AbstractCursorItemReader.verifyCursorPosition(AbstractCursorItemReader.java:365)
        at org.springframework.batch.item.database.AbstractCursorItemReader.doRead(AbstractCursorItemReader.java:449)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:601)
        at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:183)
        at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:695)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:150)
        at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:132)
        at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:120)
        at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:172)
        at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:631)
        at com.testapp.springbatchtest.io.DataExtractCursorItemReader$$EnhancerByCGLIB$$748012e7.doRead(<generated>)
        at org.springframework.batch.item.support.AbstractItemCountingItemStreamItemReader.read(AbstractItemCountingItemStreamItemReader.java:83)
        at org.springframework.batch.core.step.item.SimpleChunkProvider.doRead(SimpleChunkProvider.java:91)
        at org.springframework.batch.core.step.item.SimpleChunkProvider.read(SimpleChunkProvider.java:155)
        at org.springframework.batch.core.step.item.SimpleChunkProvider$1.doInIteration(SimpleChunkProvider.java:114)
        at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:368)
        at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215)
        at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:144)
        at org.springframework.batch.core.step.item.SimpleChunkProvider.provide(SimpleChunkProvider.java:108)
        at org.springframework.batch.core.step.item.ChunkOrientedTasklet.execute(ChunkOrientedTasklet.java:69)
        at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:395)
        at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:131)
        at org.springframework.batch.core.step.tasklet.TaskletStep$2.doInChunkContext(TaskletStep.java:267)
        at org.springframework.batch.core.scope.context.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:77)
        at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:368)
        at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215)
        at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:144)
        at org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:253)
        at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:195)
        at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:137)
        at org.springframework.batch.core.job.AbstractJob.handleStep(AbstractJob.java:380)
        at org.springframework.batch.core.job.SimpleJob.doExecute(SimpleJob.java:124)
        at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:301)
        at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:134)
        at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:49)
        at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:127)

以下是 bean 声明的示例代码。DataExtractCursorItemReader 扩展了 JdbcCursorItemReader。

@Bean
@StepScope
public DataExtractCursorItemReader cursorReaderBean() throws Exception {
    DataExtractCursorItemReader dataExtractReader = new DataExtractCursorItemReader();
    dataExtractReader.setDataSource(dataSource);
    dataExtractReader.setSql("SELECT * FROM SAMPLETABLE");
    dataExtractReader.setFetchSize(500);
    dataExtractReader.setRowMapper(new DataExtractRowMapper());

    return dataExtractReader;
}

Answer 1

verifyCursorPosition属性（似乎）只是一个检查，以防止用户在子类化 reader 时操作索引；也许是你的情况，或者也许在某些数据库平台上属性不起作用。

您可以禁用它，一切都应该正常工作 - 这只是一个防止子类化的测试。
如果修改光标位置，请检查您的代码，或者检查测试是否由于数据库驱动程序而失败。