18. ItemWriter (XML)

StaxEventItemWriter

Architecture

  XML 쓰는 과정은 읽기 과정에 대칭적입니다. StaxEventItemWriter는 Resource, marshaller, rootTagName가 필요합니다.

 

API

package io.springbatch.springbatchlecture;

import lombok.RequiredArgsConstructor;
import org.springframework.batch.core.*;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.launch.support.RunIdIncrementer;
import org.springframework.batch.item.database.*;
import org.springframework.batch.item.database.support.MySqlPagingQueryProvider;
import org.springframework.batch.item.xml.StaxEventItemWriter;
import org.springframework.batch.item.xml.builder.StaxEventItemWriterBuilder;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.ClassPathResource;
import org.springframework.core.io.FileSystemResource;
import org.springframework.oxm.xstream.XStreamMarshaller;

import javax.sql.DataSource;
import java.util.*;

@RequiredArgsConstructor
@Configuration
public class XMLConfiguration {

    private final JobBuilderFactory jobBuilderFactory;
    private final StepBuilderFactory stepBuilderFactory;
    private final DataSource dataSource;

    @Bean
    public Job job() throws Exception {
        return jobBuilderFactory.get("batchJob")
                .incrementer(new RunIdIncrementer())
                .start(step1())
                .build();
    }

    @Bean
    public Step step1() throws Exception {
        return stepBuilderFactory.get("step1")
                .<Customer, Customer>chunk(10)
                .reader(customItemReader())
                .writer(customItemWriter())
                .build();
    }

    @Bean
    public JdbcPagingItemReader<Customer> customItemReader() {

        JdbcPagingItemReader<Customer> reader = new JdbcPagingItemReader<>();

        reader.setDataSource(this.dataSource);
        reader.setFetchSize(10);
        reader.setRowMapper(new CustomerRowMapper());

        MySqlPagingQueryProvider queryProvider = new MySqlPagingQueryProvider();
        queryProvider.setSelectClause("id, firstName, lastName, birthdate");
        queryProvider.setFromClause("from customer");
        queryProvider.setWhereClause("where firstname like :firstname");

        Map<String, Order> sortKeys = new HashMap<>(1);

        sortKeys.put("id", Order.ASCENDING);
        queryProvider.setSortKeys(sortKeys);
        reader.setQueryProvider(queryProvider);

        HashMap<String, Object> parameters = new HashMap<>();
        parameters.put("firstname", "A%");

        reader.setParameterValues(parameters);

        return reader;
    }

    @Bean
    public StaxEventItemWriter customItemWriter() {
        return new StaxEventItemWriterBuilder<Customer>()
                .name("customersWriter")
                // Marshaller: XMLEventWriter를 사용해서 StartDocumnet와 EndDocument 이벤트를 필터링해서 Resources에 쓴다.
                .marshaller(itemMarshaller())
                // 작성할 파일을 나타내는 스프링 Resource
                .resource(new FileSystemResource("customer.xml"))
                // Root Element Name
                .rootTagName("customer")
                // 이미 존재하는 파일을 덮어쓸 것인지 결정
                .overwriteOutput(true)
                .build();
    }

    @Bean
    public XStreamMarshaller itemMarshaller() {
    	// StaxEventItemReader와 동일한 설정이다.
        // Map으로 alias를 지정
        // 첫번쨰 키는 조각의 루트 엘리먼트, 값은 바인딩할 객체 타입
        // 두번째 부터는 하위 엘리먼트와 각 클래스 타입
        Map<String, Class<?>> aliases = new HashMap<>();
        aliases.put("customer", Customer.class);
        aliases.put("id", Long.class);
        aliases.put("firstName", String.class);
        aliases.put("lastName", String.class);
        aliases.put("birthdate", Date.class);
        XStreamMarshaller xStreamMarshaller = new XStreamMarshaller();
        xStreamMarshaller.setAliases(aliases);
        return xStreamMarshaller;
    }
}

 

[참고자료]

인프런-스프링 배치 - Spring Boot 기반으로 개발하는 Spring Batch