Java Spring-Batch bean 的“步骤”或“作业”范围？
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"Step" or "Job" Scope for Spring-Batch beans?
提问by membersound
I'm using Spring-Batch v3.0.0 for batch imports. There is a StepScopeand a JobScope. How can I know which of them is appropriate?
我正在使用 Spring-Batch v3.0.0 进行批量导入。有一个StepScope和一个JobScope。我怎么知道哪一个是合适的？
For example, if I define a custom ItemReaderor ItemWriterthat should use a specific EntityManager, it could look like this:
例如，如果我定义了一个自定义ItemReader或ItemWriter应该使用一个特定的EntityManager，它可能如下所示：
@Bean
@Scope("step") //@Scope("job") //custom scope required to inject #jobParameters
public JpaItemWriter<T> jpaItemWriter(EntityManagerFactory emf) {
JpaItemWriter<T> writer = new JpaItemWriter<T>();
writer.setEntityManagerFactory(emf);
return writer;
}
But which scope is right here? And why?
但这里是哪个范围？为什么？
Execution with stepscope works, but I feel the itemWriters should maybe be of jobscope so that they are not recreated on every step.
使用step范围执行是有效的，但我觉得 itemWriters 应该是job范围的，这样它们就不会在每一步都重新创建。
I tried switching stepto job, but that throws following error:
Exception in thread "main" java.lang.IllegalStateException: No Scope registered for scope 'job'
我尝试切换step到job，但这会引发以下错误：
Exception in thread "main" java.lang.IllegalStateException: No Scope registered for scope 'job'
采纳答案by Eiland
Since Spring-Batch v3.0.1 you can use @JobScope
从 Spring-Batch v3.0.1 开始，您可以使用 @JobScope
Marking a @Bean as @JobScope is equivalent to marking it as @Scope(value="job", proxyMode=TARGET_CLASS)
将@Bean 标记为@JobScope 相当于将其标记为@Scope(value="job", proxyMode=TARGET_CLASS)
回答by membersound
Got it: one has to provide the scope as a bean explicit within the @Configurationfile.
明白了：必须在@Configuration文件中将作用域作为 bean 显式提供。
@Bean
public JobScope jobScope() {
return new JobScope();
}
