我创建了一个简单的单步Spring批处理作业，它从DB读取项目，处理它们并将结果写入csv . 在运行期间，我最终得到了一个
org.springframework.batch.item.WriterNotOpenException: Writer must be open before it can be written to
相关代码：
@Configuration
@EnableBatchProcessing
@EnableAutoConfiguration
public class CleanEmailJob {
@Autowired
private JobBuilderFactory jobBuilderFactory;
@Autowired
private StepBuilderFactory stepBuilderFactory;
@Autowired
public DataSource dataSource;
@Bean
public ResourcelessTransactionManager transactionManager() {
return new ResourcelessTransactionManager();
}
@Bean
public MapJobRepositoryFactoryBean mapJobRepositoryFactory(ResourcelessTransactionManager txManager)
throws Exception {
MapJobRepositoryFactoryBean factory = new MapJobRepositoryFactoryBean(txManager);
factory.afterPropertiesSet();
return factory;
}
@Bean
public JobRepository jobRepository(MapJobRepositoryFactoryBean factory) throws Exception {
return factory.getObject();
}
@Bean
public JobExplorer jobExplorer(MapJobRepositoryFactoryBean factory) {
return new SimpleJobExplorer(factory.getJobInstanceDao(), factory.getJobExecutionDao(),
factory.getStepExecutionDao(), factory.getExecutionContextDao());
}
@Bean
public SimpleJobLauncher jobLauncher(JobRepository jobRepository) {
SimpleJobLauncher launcher = new SimpleJobLauncher();
launcher.setJobRepository(jobRepository);
return launcher;
}
@Bean
public Job cleanEmailAddressesJob() throws Exception {
return jobBuilderFactory.get("cleanEmailAddresses")
.incrementer(new RunIdIncrementer())
.start(processEmailAddresses())
.build();
}
@Bean
public Step processEmailAddresses() throws UnexpectedInputException, ParseException, Exception {
return stepBuilderFactory.get("processAffiliates")
.<AffiliateEmailAddress, VerifiedAffiliateEmailAddress> chunk(10)
.reader(reader())
.processor(processor())
.writer(report())
.build();
}
@Bean
public ItemWriter<VerifiedAffiliateEmailAddress> report(){
FlatFileItemWriter<VerifiedAffiliateEmailAddress> reportWriter = new FlatFileItemWriter<VerifiedAffiliateEmailAddress>();
reportWriter.setResource(new ClassPathResource("report.csv"));
DelimitedLineAggregator<VerifiedAffiliateEmailAddress> delLineAgg = new DelimitedLineAggregator<VerifiedAffiliateEmailAddress>();
delLineAgg.setDelimiter(",");
BeanWrapperFieldExtractor<VerifiedAffiliateEmailAddress> fieldExtractor = new BeanWrapperFieldExtractor<VerifiedAffiliateEmailAddress>();
fieldExtractor.setNames(new String[] {"uniekNr", "reason"});
delLineAgg.setFieldExtractor(fieldExtractor);
reportWriter.setLineAggregator(delLineAgg);
reportWriter.setShouldDeleteIfExists(true);
return reportWriter;
}
正如文档中所描述的那样，我希望生命周期事件（打开，关闭）会自动处理，因为我处于单线程和单个编写器作业中？
2 回答
最后，结果是Spring Dev Tools干扰了我的批处理应用程序 . report.csv在我的类路径中，当写入报告文件时，Spring Dev Tools检测到我的类路径中的更改并触发重新加载应用程序，导致report.csv资源被关闭...
在我的application.properties使它再次工作
为了详细说明留下的评论，Spring Batch会在找到它们时自动注册任何
ItemStream实现，以便在步骤开始时自动打开它们 . 使用java配置时，Spring只知道返回类型是什么 . 由于您要返回ItemReader，我们不知道您的实现也实现ItemStream. 使用java配置时，我通常建议如果已知（而不是接口）则返回实现 . 这允许Spring完全反省它 . 因此，在此示例中，返回FlatFileItemReader而不是ItemReader将解决此问题 .