Question

我的ItemWriter没有写入任何文件。调试后，它将在ItemProcessor处停止。我的项目应该从Mongo数据库接收信息，然后读取它，对其进行处理，然后创建.txt文件并将信息存储在所述文件中。我在做错什么或我想念什么？

BatchConfig：

   @Configuration
   @EnableBatchProcessing
   public class BatchConfig {
private static final Logger LOG =LoggerFactory.getLogger(BatchConfig.class);

@Autowired
private JobBuilderFactory jobBuilderFactory;
@Autowired
private StepBuilderFactory stepBuilderFactory;

@Autowired
private PaymentPortalJobListener listener;
@Autowired
private MongoTemplate mongoTemplate;

@Bean
public MongoItemReader<PaymentAudit> mongoReader() throws 
UnexpectedInputException, ParseException {
    LOG.info("Inside Mongo Item Reader Method");
    MongoItemReader<PaymentAudit> reader = new MongoItemReader<PaymentAudit> 
 ();
    reader.setTemplate(mongoTemplate);
    reader.setCollection("paymentAudit");
    reader.setTargetType((Class<? extends PaymentAudit>) 
    PaymentAudit.class);
    reader.setFields("{rxFname, rxLname}");
    reader.setQuery("{rxFname, rxLname}");
    Map<String, Sort.Direction> sorts = new HashMap<String, Sort.Direction> 
    (1);
    sorts.put("rxFName", Sort.Direction.ASC);
    reader.setSort(sorts);
    return reader;
  }

 @Bean
 public ItemProcessor<PaymentAudit, PaymentAudit> processor() {
    LOG.info("Inside Processor Method");
    return new PaymentPortalNOSQLProcessor();

 }

@Bean
public ItemWriter<PaymentAudit> writer() {
    LOG.info("Inside Writer Method");
    return new PaymentPortalNOSQLWriter();
}

@Bean
Job job(JobBuilderFactory jbf, StepBuilderFactory sbf, 
 PaymentPortalNOSQLProcessor processor,
        ItemWriter<? super PaymentAudit> writer) {

    Step s1 = sbf.get("local").<PaymentAudit, 
 PaymentAudit>chunk(100).reader(mongoReader()).processor(processor)
            .writer(writer).listener(listener).build();

    return jbf.get("etl").incrementer(new 
  RunIdIncrementer()).start(s1).build();
}

}

PaymentPortalNOSQLWriter：

 @Bean
 public FileWriter Mongowriter(){
    FileWriter writer = null;
    try {
        String fullPath =OUTPUT_FILENAME + FILENAME_EXTN;
        writer = new FileWriter(fullPath);
        writer.write("[");
    } catch (IOException e) {
        LOG.error("Exception occured in MongoWriter() :: 
    ApplicationConfiguration", e);
    }
    return writer;
  }

  @Override
  public void write(List items) throws Exception {


  } 


 }

PaymentPortalJobListener

 @Autowired
private ApplicationContext appContext;


  @Override
  public void beforeStep(StepExecution stepExecution) {
      long checkpoint = System.currentTimeMillis();
    LOG.info("ExamResult Job starts at : {} " , checkpoint / (1_000 * 1.0));
  }

  @Override
   public ExitStatus afterStep(StepExecution stepExecution) {
    if(stepExecution.getStatus() == BatchStatus.COMPLETED){
        LOG.info("ExamResult job completed successfully");
        try {
            FileWriter saveWriter = 
   (FileWriter)appContext.getBean("paymentPortalWriter");
            saveWriter.write("{}");
            saveWriter.flush();
            saveWriter.close();
        } catch (BeansException | IOException e) {
            LOG.error("Exception occured in afterStep() :: PaymentPortal", 
   e);
        }
    }
    return stepExecution.getExitStatus();
}
}

PaymentPortalNOSQLProcessor：

  public class PaymentPortalNOSQLProcessor implements 
 ItemProcessor<PaymentAudit, PaymentAudit> {
 private static final Logger LOG = 
 LoggerFactory.getLogger(PaymentPortalNOSQLProcessor.class);

@Override
public PaymentAudit process(PaymentAudit bean) throws Exception {
    LOG.debug("Processor method");
    return bean;

}
}

Gradle Build：

   buildscript {
ext {
    springBootVersion = '2.0.5.RELEASE'
}
repositories {
    mavenCentral()
}
dependencies {
    classpath("org.springframework.boot:spring-boot-gradle- 
plugin:${springBootVersion}")
}
 }

 apply plugin: 'java'
 apply plugin: 'eclipse'
 apply plugin: 'org.springframework.boot'
 apply plugin: 'io.spring.dependency-management'

 group = 'com.example'
 version = '0.0.1-SNAPSHOT'
 sourceCompatibility = 1.8

 repositories {
mavenCentral()
 }


dependencies {
compile('org.springframework.boot:spring-boot-starter-batch')
compile('org.springframework.boot:spring-boot-starter-data-mongodb')

//compile("org.hsqldb:hsqldb")



compile('org.springframework.boot:spring-boot-devtools')
compileOnly('org.projectlombok:lombok')
compile group:'org.springframework.boot', name:'spring-boot-configuration- 
 processor'
testImplementation('org.springframework.boot:spring-boot-starter-test')
testImplementation('org.springframework.batch:spring-batch-test')
// https://mvnrepository.com/artifact/com.h2database/h2
//testCompile group: 'com.h2database', name: 'h2', version: '1.4.197'

 }

Answer 1

在这里，我对I / O有点困惑，所以我会尽力弄清楚。

Spring Batch的主要功能之一是声明性I / O。这意味着您不需要编写代码来处理I / O，而是您声明要执行的操作，Spring Batch将为您执行I / O。您的Mongowriter bean包含实际写入数据的代码，但实际上不应该。由于您需要写入平面文件，因此可以使用FlatFileItemWriter，例如：

@Bean
public FlatFileItemWriter<String> flatFileItemWriter() {
    return new FlatFileItemWriterBuilder<String>()
            .name("flatFileItemWriter")
            .resource(new FileSystemResource("data.txt"))
            .lineAggregator(new PassThroughLineAggregator<>())
            .build();
}

此配置代码声明了我们需要写什么内容以及在哪里写的意图，而不是实际的写操作（打开/关闭文件，调用编写器等），该操作由春季批。顺便说一句，未创建文件的问题是由于未通过代码示例在编写器上调用open方法。如果您的编写器如上所示正确配置，此问题应该得到解决。

第二点是您之所以这样做，是因为您想在所写的项目周围添加[和]（从在代码中看到writer.write("[");）。还有一次，有一种方法可以通过使用FlatFileHeaderCallback和FlatFileFooterCallback API来声明性地执行此操作。例如：

@Bean
public FlatFileItemWriter<String> flatFileItemWriter() {
    return new FlatFileItemWriterBuilder<String>()
            .name("flatFileItemWriter")
            .resource(new FileSystemResource("data.txt"))
            .lineAggregator(new PassThroughLineAggregator<>())
            .headerCallback(writer -> writer.write('['))
            .footerCallback(writer -> writer.write(']'))
            .build();
}

希望这会有所帮助。

如何获得itemWriter创建文件？

1 个答案: