我正在尝试做一个Spring批处理作业，其中
读者从数据库中读取一项
处理器创建物料清单
UnpackingItmeWriter接受项目列表，并将单个项目发送到FlatFileItemWriter。
以下是我的代码。我是从Answer那里得到的。在此配置中，我没有做正确的事，因为当我运行它时，工作甚至还没有开始。请指出正确的方向。
@EnableBatchProcessing
public class CreateFile extends ApplicationCommonConfig {
@Autowired
public JobBuilderFactory jobBuilderFactory;
@Autowired
public StepBuilderFactory stepBuilderFactory;
@Autowired
public DataSource dataSource;
@Bean
@StepScope
public JdbcCursorItemReader<ItemA> reader(
@Value("#{jobParameters}") Map<String, JobParameter> jobParameters) {
JdbcCursorItemReader<ItemA> reader = new JdbcCursorItemReader<ItemA>();
final String QUERY_SELECT = "SELECT * from table"
reader.setDataSource(dataSource);
reader.setSql(QUERY_SELECT);
reader.setRowMapper(new ItemeDeliveryRowMapper());
return reader;
}
public class ItemRowMapper implements RowMapper<ItemA> {
@Override
public ItemAmapRow(ResultSet rs, int rowNum) throws SQLException {
ItemA item= new ItemA();
item.setCode(rs.getString("Code"));
return item;
}
}
@Bean
@StepScope
public ItemProcessor<ItemA, List<ItemA>> processor(
@Value("#{jobParameters}") Map<String, JobParameter> jobParameters, @Value("#{stepExecution}")
StepExecution stepExecution) {
return new ItemAProcessor();
}
public class ItemAProcessor
implements ItemProcessor<ItemA, List<ItemA>> {
@Override
public List<ItemA> process(ItemA item) throws Exception {
List<Item> itemList = new ArrayList<ItemA>();
List<String> IdList = new ArrayList<>();
// creating List of ItemA from one ItemA
return itemList;
}
}
public class ListUnpackingItemWriter<ItemA> implements ItemWriter<List<ItemA>>, ItemStream, InitializingBean {
private ItemWriter<ItemA> delegate;
@Override
public void write(final List<? extends List<ItemA>> lists) throws Exception {
List<ItemA> consolidatedList = new ArrayList<>();
for ( List<ItemA> list : lists) {
consolidatedList.addAll(list);
}
delegate.write(consolidatedList);
}
@Override
public void afterPropertiesSet() {
Assert.notNull(delegate, "You must set a delegate!");
}
@Override
public void open(ExecutionContext executionContext) throws ItemStreamException {
if (delegate instanceof ItemStream) {
((ItemStream) delegate).open(executionContext);
}
}
@Override
public void update(ExecutionContext executionContext) throws ItemStreamException{
if (delegate instanceof ItemStream) {
((ItemStream) delegate).update(executionContext);
}
}
@Override
public void close() {
if (delegate instanceof ItemStream) {
((ItemStream) delegate).close();
}
}
public void setDelegate(ItemWriter<ItemA> delegate) {
this.delegate = delegate;
}
}
@Bean
@StepScope
public FlatFileItemWriter<ItemA> flatWriter() {
FlatFileItemWriter<ItemA> writer = new FlatFileItemWriter<ItemA>();
writer.setResource(new FileSystemResource("C:/dev/doc.txt"));
writer.setHeaderCallback(new FlatFileHeaderCallback() {
@Override
public void writeHeader(Writer writer) throws IOException {
writer.write("Header");
}
});
writer.setLineAggregator(new DelimitedLineAggregator<Item>() {
{
setDelimiter("|");
setFieldExtractor(new BeanWrapperFieldExtractor<Item>() {
{
setNames(new String[] { "Code" });
}
});
}
});
writer.setFooterCallback(new FlatFileFooterCallback() {
@Override
public void writeFooter(Writer writer) throws IOException {
writer.write("Footer");
}
});
return writer;
}
@Bean
@StepScope
public ItemWriter<List<ItemA>> writer(@Value("#{jobParameters}") Map<String, JobParameter> jobParameters) {
ListUnpackingItemWriter<ItemA> listUnpackingItemWriter = new ListUnpackingItemWriter<ItemA>();
listUnpackingItemWriter.setDelegate(flatWriter());
return listUnpackingItemWriter;
}
public Step step1(StepBuilderFactory stepBuilderFactory, ItemReader<ItemA> reader,
ItemProcessor<ItemA, List<ItemA>> processor,
ItemWriter<List<ItemA>> flatItemWriter) {
return stepBuilderFactory.get("step1").<ItemA, List<ItemA>>chunk(1).reader(reader)
.processor(processor).writer(flatItemWriter).build();
}
@Bean
public Job createFileJob(JobBuilderFactory jobs, Step s1) {
return jobBuilderFactory.get("createFileJob").incrementer(new RunIdIncrementer())
.listener(listener()).flow(s1).end().build();
}
}
编辑： 打印堆栈
2018-11-11 22:17:53 [main] INFO c.t.t.l.Launcher - inside try
2018-11-11 22:17:54 [main] INFO c.t.t.c.CreateFile - inside JdbcCursorItemReader
2018-11-11 22:17:55 [main] ERROR o.s.batch.core.step.AbstractStep - Encountered an error executing step step1 in job createJob
org.springframework.batch.item.WriterNotOpenException: Writer must be open before it can be written to
at org.springframework.batch.item.file.FlatFileItemWriter.write(FlatFileItemWriter.java:255) ~[spring-batch-infrastructure-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at com.stackoverflow.spring.config.CreateFile$ListUnpackingItemWriter.write(CreateFile.java:209) ~[classes/:na]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_181]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_181]
at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_181]
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317) [spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190) [spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) [spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.aop.support.DelegatingIntroductionInterceptor.doProceed(DelegatingIntroductionInterceptor.java:133) ~[spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.aop.support.DelegatingIntroductionInterceptor.invoke(DelegatingIntroductionInterceptor.java:121) ~[spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) [spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207) [spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at com.sun.proxy.$Proxy19.write(Unknown Source) ~[na:na]
at org.springframework.batch.core.step.item.SimpleChunkProcessor.writeItems(SimpleChunkProcessor.java:175) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.step.item.SimpleChunkProcessor.doWrite(SimpleChunkProcessor.java:151) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.step.item.SimpleChunkProcessor.write(SimpleChunkProcessor.java:274) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.step.item.SimpleChunkProcessor.process(SimpleChunkProcessor.java:199) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.step.item.ChunkOrientedTasklet.execute(ChunkOrientedTasklet.java:75) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:406) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.step.tasklet.TaskletStep$ChunkTransactionCallback.doInTransaction(TaskletStep.java:330) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:133) ~[spring-tx-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.batch.core.step.tasklet.TaskletStep$2.doInChunkContext(TaskletStep.java:271) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.scope.context.StepContextRepeatCallback.doInIteration(StepContextRepeatCallback.java:81) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.repeat.support.RepeatTemplate.getNextResult(RepeatTemplate.java:374) ~[spring-batch-infrastructure-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.repeat.support.RepeatTemplate.executeInternal(RepeatTemplate.java:215) ~[spring-batch-infrastructure-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.repeat.support.RepeatTemplate.iterate(RepeatTemplate.java:144) ~[spring-batch-infrastructure-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.step.tasklet.TaskletStep.doExecute(TaskletStep.java:257) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.step.AbstractStep.execute(AbstractStep.java:200) ~[spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.job.SimpleStepHandler.handleStep(SimpleStepHandler.java:148) [spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.job.flow.JobFlowExecutor.executeStep(JobFlowExecutor.java:64) [spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.job.flow.support.state.StepState.handle(StepState.java:67) [spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.job.flow.support.SimpleFlow.resume(SimpleFlow.java:169) [spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.job.flow.support.SimpleFlow.start(SimpleFlow.java:144) [spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.job.flow.FlowJob.doExecute(FlowJob.java:134) [spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.job.AbstractJob.execute(AbstractJob.java:306) [spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.batch.core.launch.support.SimpleJobLauncher$1.run(SimpleJobLauncher.java:135) [spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.core.task.SyncTaskExecutor.execute(SyncTaskExecutor.java:50) [spring-core-4.3.4.RELEASE.jar:4.3.4.RELEASE]
at org.springframework.batch.core.launch.support.SimpleJobLauncher.run(SimpleJobLauncher.java:128) [spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_181]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source) ~[na:1.8.0_181]
at java.lang.reflect.Method.invoke(Unknown Source) ~[na:1.8.0_181]
at org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(AopUtils.java:317) [spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinpoint(ReflectiveMethodInvocation.java:190) [spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) [spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.batch.core.configuration.annotation.SimpleBatchConfiguration$PassthruAdvice.invoke(SimpleBatchConfiguration.java:127) [spring-batch-core-3.0.7.RELEASE.jar:3.0.7.RELEASE]
at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) [spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:207) [spring-aop-4.0.5.RELEASE.jar:4.0.5.RELEASE]
at com.sun.proxy.$Proxy26.run(Unknown Source) [na:na]
at com.stackoverflow.spring.launchers.Launcher.Create(Launcher.java:701) [classes/:na]
at com.stackoverflow.spring.launchers.Launcher.main(Launcher.java:73) [classes/:na]
答案 0 :(得分：0)
只需在open()之前用参数new ExecutionContext()调用方法delegate.write(consolidatedList);，即可打开作者
open (new ExecutionContext ());
delegate.write(consolidatedList);
答案 1 :(得分：0)
从ItemStream中删除ListUnpackingItemWriter（及其实现），并使用.stream()将flatWriter()注册为流，以便SB自动管理平面文件流