spring batch处理数据模板（Reader-Processor-Writer模式）

步骤监听器

@Component
public class StepListener implements StepExecutionListener {private StepExecution stepExecution;public StepExecution getStepExecution() {return this.stepExecution;}@Overridepublic void beforeStep(StepExecution stepExecution) {this.stepExecution = stepExecution;}@Overridepublic ExitStatus afterStep(StepExecution stepExecution) {return null;}
}

读

@Component
@StepScope
public class ProductItemReader implements ItemReader<Product> {private Iterator<Product> iterator;private final StepListener stepListener;private final XxxRepository xxxRepository;public ProductItemReader(StepListener stepListener,XxxRepository xxxRepository) {this.stepListener = stepListener;this.xxxRepository = xxxRepository;}@Overridepublic Product read() {// 利用repository读取数据this.iterator = xxxRepository.xxx();// StepExecution 在 Step 执行时才可用，必须懒初始化StepExecution stepExecution = stepListener.getStepExecution();ExecutionContext executionContext = stepExecution.getExecutionContext();// 可设置STEP内上下文return iterator.hasNext() ? iterator.next() : null;}
}

处理

@Slf4j
@StepScope
@Component("productProcessor")
public class ProductProcessor implements ItemProcessor<Product, Product> {private final StepListener stepListener;public ProductProcessor(@Qualifier("stepListener") StepListener stepListener) {this.stepListener = stepListener;}@Overridepublic Product process(Product product) {// 从步骤域内读取数据或设置数据StepExecution stepExecution = productStepListener.getStepExecution();ExecutionContext executionContext = stepExecution.getExecutionContext();return product;}}

写

@Slf4j
@Component("productWriter")
public class ProductWriter implements ItemWriter<Product> {private final XxxRepository repository;private final StepListener stepListener;public ProductWriter(@Qualifier(value = "productRepository") XxxRepository xxxRepository,@Qualifier(value = "stepListener") StepListener stepListener) {this.repository = xxxRepository;this.stepListener = stepListener;}@Overridepublic void write(List<? extends Product> items){StepExecution stepExecution = this.stepListener.getStepExecution();ExecutionContext executionContext = stepExecution.getExecutionContext();items.forEach( product ->  {...});}
}

定义步骤

@Bean
public Step printStep(){TaskletStep taskletStep = stepBuilderFactory.get("testStep").listener(stepListener).<Product, Product>chunk(10).reader(productItemReader).processor(productProcessor).writer(productWriter).build();return taskletStep;
}

使用步骤

@Bean
public Job testJob(){return jobBuilderFactory.get("productJob").start(printStep())....build();
}