基于spring batch，写一段代码，逻辑为通过itemreadr读取DB2数据库获取数据，通过itemprossor判断数据中的日期是否大于当前

的日期，如果大于则将数据写入到CSV文件中。

@Configuration
@EnableBatchProcessing
public class BatchConfig {

    @Autowired
    public JobBuilderFactory jobBuilderFactory;

    @Autowired
    public StepBuilderFactory stepBuilderFactory;

    @Autowired
    public DataSource dataSource;

    @Bean
    public Job exportJob() {
        return jobBuilderFactory.get("exportJob")
                .incrementer(new RunIdIncrementer())
                .flow(exportStep())
                .end()
                .build();
    }

    @Bean
    public Step exportStep() {
        return stepBuilderFactory.get("exportStep")
                .<MyData, MyData>chunk(10)
                .reader(reader())
                .processor(processor())
                .writer(writer())
                .build();
    }

    @Bean
    public JdbcCursorItemReader<MyData> reader() {
        JdbcCursorItemReader<MyData> reader = new JdbcCursorItemReader<>();
        reader.setDataSource(dataSource);
        reader.setSql("SELECT * FROM MY_TABLE");
        reader.setRowMapper(new BeanPropertyRowMapper<>(MyData.class));
        return reader;
    }

    @Bean
    public ItemProcessor<MyData, MyData> processor() {
        return item -> {
            LocalDate currentDate = LocalDate.now();
            if (item.getDate().isAfter(currentDate)) {
                return item;
            } else {
                return null;
            }
        };
    }

    @Bean
    public FlatFileItemWriter<MyData> writer() {
        FlatFileItemWriter<MyData> writer = new FlatFileItemWriter<>();
        writer.setResource(new FileSystemResource("output.csv"));
        DelimitedLineAggregator<MyData> lineAggregator = new DelimitedLineAggregator<>();
        lineAggregator.setDelimiter(",");
        BeanWrapperFieldExtractor<MyData> fieldExtractor = new BeanWrapperFieldExtractor<>();
        fieldExtractor.setNames(new String[] {"id", "name", "date"});
        lineAggregator.setFieldExtractor(fieldExtractor);
        writer.setLineAggregator(lineAggregator);
        return writer;
    }

}

上述代码中，我们定义了一个`exportJob`和一个`exportStep`，并且在`exportStep`中配置了一个`reader`、一个`processor`和一个`writer`。其中`reader`使用了`JdbcCursorItemReader`来从DB2数据库中读取数据，`processor`判断数据中的日期是否大于当前日期，`writer`将符合要求的数据写入到CSV文件中。最后我们在`exportJob`中添加了一个`RunIdIncrementer`，以确保每次运行时都会生成一个新的实例。