Spring Batch Reader, Processor, Writer

Reader, Processor, Writer

Use ItemReader, ItemProcessor, ItemWriter

Example

This example is based on Spring Documentation Creating a Batch Service

Use file as read source.
Save process in HSQL
Write data into MySQL

Preparation

Create table in MySQL.

CREATE TABLE `people` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) NOT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB;

DataSourceConfig.java

public class DataSourceConfiguration {

    @Bean
    @Primary
    public DataSource hsqldbDataSource() throws SQLException {
        final SimpleDriverDataSource dataSource = new SimpleDriverDataSource();
        dataSource.setDriver(new org.hsqldb.jdbcDriver());
        dataSource.setUrl("jdbc:hsqldb:mem:mydb");
        dataSource.setUsername("sa");
        dataSource.setPassword("");
        return dataSource;
    }

    @Bean
    public DataSource mysqlDataSource() throws SQLException {
        final SimpleDriverDataSource dataSource = new SimpleDriverDataSource();
        dataSource.setDriver(new com.mysql.jdbc.Driver());
        dataSource.setUrl("jdbc:mysql://localhost/test");
        dataSource.setUsername("root");
        dataSource.setPassword("atmarkplant");
        return dataSource;
    }
}

Person.java(Model)

public class Person {

    private String name;

    public Person() {

    }

    public Person(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "name : " + this.name;
    }
}

PersonItemProcessor.java(Processor)

public class PersonItemProcessor implements ItemProcessor<Person, Person> {

    private static final Logger log = LoggerFactory.getLogger(PersonItemProcessor.class);

    @Override
    public Person process(Person item) throws Exception {
        final String name = item.getName().toUpperCase();
        final Person transformedPerson = new Person(name);
        log.info("Converting (" + item + ") into (" + transformedPerson + ")");
        return transformedPerson;
    }
}

BatchConfiguration.java(Config)

@Configuration
@EnableBatchProcessing
@ComponentScan(basePackageClasses = DefaultBatchConfigurer.class)   // @Componentscan
@EnableAutoConfiguration
@Import({DataSourceConfiguration.class})                // @Import
public class BatchConfiguration {

    @Autowired
    private JobBuilderFactory jobBuilderFactory;

    @Autowired
    private StepBuilderFactory stepBuilderFactory;

    @Autowired
    private DataSourceConfiguration dataSourceConfig;

    // tag::readerwriterprocessor[]
    @Bean
    public FlatFileItemReader<Person> reader() {
        // FlatFileItemReader : oneline ? csv parsing
        FlatFileItemReader<Person> reader = new FlatFileItemReader<Person>();
        reader.setResource(new ClassPathResource("data.csv"));
        reader.setLineMapper(new DefaultLineMapper<Person>() {{
            setLineTokenizer(new DelimitedLineTokenizer() {{
                setNames(new String[] { "name"});
            }});
            setFieldSetMapper(new BeanWrapperFieldSetMapper<Person>() {{
                setTargetType(Person.class);
            }});
        }});
        return reader;
    }

    @Bean
    public PersonItemProcessor processor() {
        return new PersonItemProcessor();
    }

    @Bean
    public JdbcBatchItemWriter<Person> writer() {
        JdbcBatchItemWriter<Person> writer = new JdbcBatchItemWriter<Person>();
        writer.setItemSqlParameterSourceProvider(new BeanPropertyItemSqlParameterSourceProvider<Person>());
        writer.setSql("INSERT INTO people (name) VALUES (:name)");
        try {
            writer.setDataSource(dataSourceConfig.mysqlDataSource());
        }
        catch (SQLException e) {
        }
        return writer;
    }

    // end::readerwriterprocessor[]

    // tag::jobstep[]
    @Bean
    public Job importUserJob() {
        return jobBuilderFactory.get("importUserJob")
                .incrementer(new RunIdIncrementer())
                .flow(step1())
                .end()
                .build();
    }

    @Bean
    public Step step1() {
        return stepBuilderFactory.get("step1")
                .<Person, Person> chunk(10)   // decide type?
                .reader(reader())
                .processor(processor())
                .writer(writer())
                .build();
    }
    // end::jobstep[]
}