使用Compositewriter的FlatfileItemWriter示例

@Configuration
public class FlatFileWriterConfig {

    @Autowired
    private StepBuilderFactory stepBuilderFactory;

    @Autowired
    private JobBuilderFactory jobBuilderFactory;

    @Bean
    public ItemReader<User> itemReader() {
        // 定义ItemReader，从数据库或其他来源读取数据
        // 这里假设从数据库读取User对象列表作为示例
        return new JdbcCursorItemReaderBuilder<User>()
                .dataSource(dataSource)
                .sql("SELECT id, name, email FROM users")
                .rowMapper(new UserRowMapper())
                .build();
    }

    @Bean
    public ItemWriter<User> flatFileItemWriter() {
        // 定义FlatFileItemWriter，将数据写入平面文件
        FlatFileItemWriter<User> writer = new FlatFileItemWriter<>();
        writer.setResource(new FileSystemResource("output.txt")); // 输出文件路径
        writer.setLineAggregator(new PassThroughLineAggregator<>()); // 按原样输出每行数据
        return writer;
    }

    @Bean
    public ItemWriter<User> compositeItemWriter() {
        // 使用CompositeItemWriter将数据同时写入多个目标
        CompositeItemWriter<User> writer = new CompositeItemWriter<>();
        writer.setDelegates(Arrays.asList(flatFileItemWriter(), otherItemWriter())); // 可以添加多个ItemWriter
        return writer;
    }

    @Bean
    public Step myStep() {
        return stepBuilderFactory.get("myStep")
                .<User, User>chunk(10)
                .reader(itemReader())
                .writer(compositeItemWriter())
                .build();
    }

    @Bean
    public Job myJob() {
        return jobBuilderFactory.get("myJob")
                .start(myStep())
                .build();
    }
}