19. ItemWriter (Json)

JsonFileItemWriter

Architecture

  객체를 받아 JSON String으로 변환하는 역할을 합니다.

 

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.json.JacksonJsonObjectMarshaller;
import org.springframework.batch.item.json.JsonFileItemWriter;
import org.springframework.batch.item.json.builder.JsonFileItemWriterBuilder;
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 JsonConfiguration {

    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 JsonFileItemWriter<Customer> customItemWriter() {
        return new JsonFileItemWriterBuilder<Customer>()
                .jsonObjectMarshaller(new JacksonJsonObjectMarshaller<>())
                .resource(new ClassPathResource("customer.json"))
                .name("customerJsonFileItemWriter")
                .build();
    }
}

 

[참고자료]

인프런-스프링 배치 - Spring Boot 기반으로 개발하는 Spring Batch