Category Hierarchy

@Bean
public JdbcPagingItemReader<Customer> customerPagingItemReader(){
    // reading database records using JDBC in a paging fashion
    JdbcPagingItemReader<Customer> reader = new JdbcPagingItemReader<>();
    reader.setDataSource(this.dataSource);
    reader.setFetchSize(1000);
    reader.setRowMapper(new CustomerRowMapper());

    // Sort Keys
    Map<String, Order> sortKeys = new HashMap<>();
    sortKeys.put("cust_id", Order.ASCENDING);

    // POSTGRES implementation of a PagingQueryProvider using database specific features.
    PostgresPagingQueryProvider queryProvider = new PostgresPagingQueryProvider();
    queryProvider.setSelectClause("*");
    queryProvider.setFromClause("from customer");
    queryProvider.setSortKeys(sortKeys);

    reader.setQueryProvider(queryProvider);

    return reader;
}

@Bean
    public Job multithreadedJob() {
        return this.jobBuilderFactory.get("multithreadedJob")
                .start(step1())
                .build();
    }

    @Bean
    public Step step1() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        taskExecutor.setCorePoolSize(4);
        taskExecutor.setMaxPoolSize(4);
        taskExecutor.afterPropertiesSet();

        return this.stepBuilderFactory.get("step1")
                .<Transaction, Transaction>chunk(100)
                .reader(fileTransactionReader(null))
                .writer(writer(null))
                .taskExecutor(taskExecutor)
                .build();
    }