如何让itemWriter创建文件？
如何让itemWriter创建文件？
提问于 2018-10-31 18:25:22
我的ItemWriter没有写任何文件。调试后，它在ItemProcessor处停止。我的项目应该从Mongo接收信息，然后读取它，处理它，然后创建.txt文件并将信息存储在该文件中。我做错了什么或者我错过了什么？
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;
}
}分级建造：
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'
}回答 1
Stack Overflow用户
发布于 2018-11-02 07:46:05
我在这里看到一个关于I/O的小混乱，所以我会尽量说明清楚。
Spring批处理的主要特性之一是声明性I/O，这意味着您不需要编写代码来处理I/O，而是声明要做什么，Spring批处理将为您完成I/O。您的Mongowriter bean包含实际编写数据的代码，但它不应该。
@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编写的内容以及编写它的位置，而不是Spring批处理处理的实际写入(打开/关闭文件、调用写入器等)。顺便说一句，没有创建文件的问题是由于您的代码示例没有在编写器上调用open方法。如果您的作者配置正确，如上文所示，则应修复此问题。
第二点是，您可能是这样做的，因为您希望在编写的项周围添加[和] (从代码中看到writer.write("["); )。另一次，可以通过使用FlatFileHeaderCallback和FlatFileFooterCallback API以声明的方式进行此操作。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();
}希望这能有所帮助。
页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/53089841
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