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[英]SPRING-BATCH ERROR: No context holder available for step scope
[英]How to access execution context from a Spring Batch Step? Error: No context holder available for job scope
我试图通过将它注入我的步骤来在运行时设置我的 spring 批处理作业的块大小,如下所示:
@Bean
@JobScope
@Qualifier("myStep")
public Step myStep(@Value("#{jobExecutionContext['chunkSize']}") Integer chunkSize, StepBuilderFactory stepBuilderFactory, ItemReader<Object> reader, ItemWriter<Object> writer, Listener listener) {
return stepBuilderFactory.get("myStep")
.<Object, Object>chunk(chunkSize)
.reader(reader)
.writer(writer)
.listener(listener)
.build();
}
但我收到以下错误: java.lang.IllegalStateException: No context holder available for job scope
我在网上做了一些研究,但无法理解为什么我会遇到这个例外。 如果您能帮助我理解此错误的含义以及如何解决它,我将不胜感激。 谢谢!
我在数据库表中为需要运行的每个作业定义了块大小。 块大小通过在作业中的此步骤之前运行的 tasklet 放入执行上下文中
这是一个按预期工作的快速示例:
import java.util.Arrays;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.JobScope;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.batch.core.listener.ChunkListenerSupport;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.item.support.ListItemReader;
import org.springframework.batch.repeat.RepeatStatus;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
@EnableBatchProcessing
public class SO64447747WithJobExecutionContext {
@Bean
public Step step1(StepBuilderFactory stepBuilderFactory) {
return stepBuilderFactory.get("step1")
.tasklet((contribution, chunkContext) -> {
// TODO get chunk size from table and put in job execution context
chunkContext.getStepContext().getStepExecution().getJobExecution().getExecutionContext().put("chunkSize", 2);
return RepeatStatus.FINISHED;
})
.build();
}
@Bean
@JobScope
public Step step2(StepBuilderFactory stepBuilderFactory, @Value("#{jobExecutionContext['chunkSize']}") Integer chunkSize) {
return stepBuilderFactory.get("step2")
.<Integer, Integer>chunk(chunkSize)
.reader(new ListItemReader<>(Arrays.asList(1, 2, 3, 4)))
.writer(items -> items.forEach(System.out::println))
.listener(new ChunkListenerSupport() {
@Override
public void beforeChunk(ChunkContext context) {
System.out.println("starting to work on a new chunk of size " + chunkSize);
}
})
.build();
}
@Bean
public Job job(JobBuilderFactory jobBuilderFactory, StepBuilderFactory stepBuilderFactory) {
return jobBuilderFactory.get("job")
.start(step1(stepBuilderFactory))
.next(step2(stepBuilderFactory, null))
.build();
}
public static void main(String[] args) throws Exception {
ApplicationContext context = new AnnotationConfigApplicationContext(SO64447747WithJobExecutionContext.class);
JobLauncher jobLauncher = context.getBean(JobLauncher.class);
Job job = context.getBean(Job.class);
jobLauncher.run(job, new JobParameters());
}
}
这将打印以下输出,而没有您提到的错误:
starting to work on a new chunk of size 2
1
2
starting to work on a new chunk of size 2
3
4
我试图将块大小作为作业参数传递,但我看到有关作业范围的相同问题。
当将chunkSize
作为作业参数传递时,相同的方法毫无例外地工作:
import java.util.Arrays;
import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.JobParametersBuilder;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.JobScope;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.batch.core.listener.ChunkListenerSupport;
import org.springframework.batch.core.scope.context.ChunkContext;
import org.springframework.batch.item.support.ListItemReader;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
@EnableBatchProcessing
public class SO64447747WithJobParameter {
@Bean
@JobScope
public Step step(StepBuilderFactory stepBuilderFactory, @Value("#{jobParameters['chunkSize']}") Integer chunkSize) {
return stepBuilderFactory.get("step")
.<Integer, Integer>chunk(chunkSize)
.reader(new ListItemReader<>(Arrays.asList(1, 2, 3, 4)))
.writer(items -> items.forEach(System.out::println))
.listener(new ChunkListenerSupport() {
@Override
public void beforeChunk(ChunkContext context) {
System.out.println("starting to work on a new chunk of size " + chunkSize);
}
})
.build();
}
@Bean
public Job job(JobBuilderFactory jobBuilderFactory, StepBuilderFactory stepBuilderFactory) {
return jobBuilderFactory.get("job")
.start(step(stepBuilderFactory, null))
.build();
}
public static void main(String[] args) throws Exception {
ApplicationContext context = new AnnotationConfigApplicationContext(SO64447747WithJobParameter.class);
JobLauncher jobLauncher = context.getBean(JobLauncher.class);
Job job = context.getBean(Job.class);
JobParameters jobParameters = new JobParametersBuilder()
.addLong("chunkSize", 2L)
.toJobParameters();
jobLauncher.run(job, jobParameters);
}
}
这给出了与第一个示例相同的输出。
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