Spring Batch 并行处理 - 运行时文件分割

Question

我有一个简单的 Spring Batch，它从文件中读取 100 万条记录并将其打印在控制台上。

现在，我想在 N 个服务器上部署这一批，假设 N=5。

如何确保所有服务器实例都不会读取相同的记录？

如 - 我如何适当地分割文件中的记录（100万/5）以实现优化结果？

请帮忙提供代码示例。谢谢。

Answer 1

正如迈克尔所建议的，您可以使用系统命令分割文件，然后用于并行MultiResourcePartitioner处理分割的文件。我就是这样做的

@Bean
    public Partitioner partitioner() {
        MultiResourcePartitioner partitioner = new MultiResourcePartitioner();
        ClassLoader cl = this.getClass().getClassLoader();
        ResourcePatternResolver resolver = new PathMatchingResourcePatternResolver(cl);
        Resource[] resources = resolver.getResources("file:" + filePath + "/"+"*.csv");     
        partitioner.setResources(resources);
        partitioner.partition(10);      
        return partitioner;
    }

    @Bean
    public TaskExecutor taskExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        taskExecutor.setMaxPoolSize(4);
        taskExecutor.afterPropertiesSet();
        return taskExecutor;
    }   

    @Bean
    @Qualifier("masterStep")
    public Step masterStep() {
        return stepBuilderFactory.get("masterStep")
                .partitioner(ProcessDataStep())
                .partitioner("ProcessDataStep",partitioner())   
                .taskExecutor(taskExecutor())
                .listener(pcStressStepListener)
                .build();
    }


    @Bean
    @Qualifier("processData")
    public Step processData() {
        return stepBuilderFactory.get("processData")
                .<pojo, pojo> chunk(5000)
                .reader(reader)             
                .processor(processor())
                .writer(writer)         
                .build();
    }



    @Bean(name="reader")
    @StepScope
    public FlatFileItemReader<pojo> reader(@Value("#{stepExecutionContext['fileName']}") String filename) {

        FlatFileItemReader<pojo> reader = new FlatFileItemReader<>();
        reader.setResource(new UrlResource(filename));
        reader.setLineMapper(new DefaultLineMapper<pojo>() {
            {
                setLineTokenizer(new DelimitedLineTokenizer() {
                    {
                        setNames(FILE HEADER);


                    }
                });
                setFieldSetMapper(new BeanWrapperFieldSetMapper<pojo>() {
                    {
                        setTargetType(pojo.class);
                    }
                });
            }
        });
        return reader;
    }