如何读取Spring batch中不同列数的多行文件

@Configuration
public class BatchConfig {

    @Autowired
    private JobBuilderFactory jobBuilderFactory;

    @Autowired
    private StepBuilderFactory stepBuilderFactory;

    @Bean
    public FlatFileItemReader<MyEntity> itemReader() {
        FlatFileItemReader<MyEntity> reader = new FlatFileItemReader<>();
        reader.setResource(new ClassPathResource("data.csv"));
        reader.setLineMapper(lineMapper());
        return reader;
    }

    @Bean
    public LineMapper<MyEntity> lineMapper() {
        DefaultLineMapper<MyEntity> lineMapper = new DefaultLineMapper<>();
        DelimitedLineTokenizer tokenizer = new DelimitedLineTokenizer();
        tokenizer.setNames("column1", "column2", "column3"); // 设置列名
        lineMapper.setLineTokenizer(tokenizer);
        lineMapper.setFieldSetMapper(new BeanWrapperFieldSetMapper<MyEntity>() {{
            setTargetType(MyEntity.class);
        }});
        return lineMapper;
    }

    @Bean
    public ItemProcessor<MyEntity, MyEntity> itemProcessor() {
        // 设置数据处理逻辑
        return item -> {
            // 处理数据
            return item;
        };
    }

    @Bean
    public ItemWriter<MyEntity> itemWriter() {
        // 设置数据写入逻辑
        return items -> {
            // 写入数据
        };
    }

    @Bean
    public Step step(ItemReader<MyEntity> itemReader, ItemProcessor<MyEntity, MyEntity> itemProcessor, ItemWriter<MyEntity> itemWriter) {
        return stepBuilderFactory.get("step")
                .<MyEntity, MyEntity>chunk(10)
                .reader(itemReader)
                .processor(itemProcessor)
                .writer(itemWriter)
                .build();
    }

    @Bean
    public Job job(Step step) {
        return jobBuilderFactory.get("job")
                .start(step)
                .build();
    }
}