春季批處理：作業實例在使用注釋時按順序運行

Question

我對Spring批處理作業有一個簡單的注釋配置，如下所示：

@Configuration
@EnableBatchProcessing
public abstract class AbstractFileLoader<T> {

    private static final String FILE_PATTERN = "*.dat";


    @Bean
    @StepScope
    @Value("#{stepExecutionContext['fileName']}")
    public FlatFileItemReader<T> reader(String file) {
        FlatFileItemReader<T> reader = new FlatFileItemReader<T>();
        String path = file.substring(file.indexOf(":") + 1, file.length());
        FileSystemResource resource = new FileSystemResource(path);
        reader.setResource(resource);
        DefaultLineMapper<T> lineMapper = new DefaultLineMapper<T>();
        lineMapper.setFieldSetMapper(getFieldSetMapper());
        DelimitedLineTokenizer tokenizer = new DelimitedLineTokenizer(",");
        tokenizer.setNames(getColumnNames());
        lineMapper.setLineTokenizer(tokenizer);
        reader.setLineMapper(lineMapper);
        reader.setLinesToSkip(1);
        return reader;
    }

    @Bean
    public ItemProcessor<T, T> processor() {
        // TODO add transformations here
        return null;
    }

    //Exception when using JobScope for the writer
    @Bean

    public ItemWriter<T> writer() {
        ListItemWriter<T> writer = new ListItemWriter<T>();
        return writer;
    }


    @Bean
    public Job loaderJob(JobBuilderFactory jobs, Step s1,
            JobExecutionListener listener) {
        return jobs.get(getLoaderName()).incrementer(new RunIdIncrementer())
                .listener(listener).start(s1).build();
    }

    @Bean
    public Step readStep(StepBuilderFactory stepBuilderFactory,
            ItemReader<T> reader, ItemWriter<T> writer,
            ItemProcessor<T, T> processor, TaskExecutor taskExecutor,
            ResourcePatternResolver resolver) {

        final Step readerStep = stepBuilderFactory
                .get(getLoaderName() + " ReadStep:slave").<T, T> chunk(25254)
                .reader(reader).processor(processor).writer(writer)
                .taskExecutor(taskExecutor).throttleLimit(16).build();

        final Step partitionedStep = stepBuilderFactory
                .get(getLoaderName() + " ReadStep:master")
                .partitioner(readerStep)
                .partitioner(getLoaderName() + " ReadStep:slave",
                        partitioner(resolver)).taskExecutor(taskExecutor)
                .build();

        return partitionedStep;

    }


    @Bean
    public TaskExecutor taskExecutor() {
        return new SimpleAsyncTaskExecutor();
    }

    @Bean
    public Partitioner partitioner(
            ResourcePatternResolver resourcePatternResolver) {
        MultiResourcePartitioner partitioner = new MultiResourcePartitioner();
        Resource[] resources;
        try {
            resources = resourcePatternResolver.getResources("file:"
                    + getFilesPath() + FILE_PATTERN);
        } catch (IOException e) {
            throw new RuntimeException(
                    "I/O problems when resolving the input file pattern.", e);
        }
        partitioner.setResources(resources);
        return partitioner;
    }

    @Bean
    public JobExecutionListener listener(ItemWriter<T> writer) {
        /* org.springframework.batch.core.scope.StepScope scope; */
        return new JobCompletionNotificationListener<T>(writer);
    }

    public abstract FieldSetMapper<T> getFieldSetMapper();

    public abstract String getFilesPath();

    public abstract String getLoaderName();

    public abstract String[] getColumnNames();

}

當我使用兩個不同的作業參數運行相同的作業實例時，兩個實例將順序運行，而不是並行運行。 我配置了一個SimpleAysncTaskExecutor bean，我認為這應該導致作業被異步觸發。

我是否需要向此類添加更多配置以使作業實例並行執行？

Answer 1

您必須配置要用來啟動作業的jobLauncher ，以使用TaskExecutor （或單獨的池）。 最簡單的方法是覆蓋bean：

@Bean
JobLauncher jobLauncher(JobRepository jobRepository) {
    new SimpleJobLauncher(
            taskExecutor: taskExecutor(),
            jobRepository: jobRepository)
}

不要被將要記錄的警告所迷惑，該警告指出將使用同步任務執行器。 這是由於創建了一個額外的實例，這是由於Spring Batch用於配置它在SimpleBatchConfiguration提供的Bean的方式非常笨拙（長話短說，如果要擺脫警告，則需要提供BatchConfigurer Bean並指定如何創建其他4個Bean，即使您只想更改一個也是如此。

請注意，此處相同的工作無關緊要。 問題在於，默認情況下，作業啟動器將在同一線程上啟動作業。