Spring Batch 처음 실행해봅니다. 👨‍💻 ( 완전 간단 예제 )

 

 

전체 코드 입니다.

 

 

package com.rsn.dic.RsnDictionaryBatch.datamailsend;

import org.springframework.batch.core.*;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.support.DefaultBatchConfiguration;
import org.springframework.batch.core.job.builder.JobBuilder;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.batch.core.repository.JobRepository;
import org.springframework.batch.core.step.builder.StepBuilder;
import org.springframework.batch.item.ItemReader;
import org.springframework.batch.item.ItemWriter;
import org.springframework.boot.CommandLineRunner;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.transaction.PlatformTransactionManager;

import java.nio.charset.Charset;
import java.nio.charset.StandardCharsets;
import java.util.Date;

@Configuration
@EnableBatchProcessing
public class DataMailSendConfig extends DefaultBatchConfiguration {

    @Bean
    public CommandLineRunner commandLineRunner(JobLauncher jobLauncher, Job job) {
        return new CommandLineRunner() {
            @Override
            public void run(String... args) throws Exception {

                System.out.println("Job Started !!");

                JobParametersBuilder paramsBuilder = new JobParametersBuilder();
                paramsBuilder.addString("currentTime", String.valueOf(new Date()));
                JobParameters parameters = paramsBuilder.toJobParameters();

                JobExecution jobExecution = jobLauncher.run(job, parameters);
                System.out.println("Job Status : " + jobExecution.getStatus());
            }
        };
    }

    @Bean
    public Job job(JobRepository jobRepository, PlatformTransactionManager transactionManager){
        return new JobBuilder("job", jobRepository)
                .start(step(jobRepository, transactionManager))
                .build();
    }

    @Bean
    public Step step(JobRepository jobRepository, PlatformTransactionManager transactionManager){
        return new StepBuilder("step",jobRepository)
                .<String, String>chunk(10, transactionManager)
                .reader(itemReader())
                .writer(itemWriter())
                .build();
    }

    private int cnt = 0;

    @Bean
    public ItemReader<String> itemReader(){
        return new ItemReader<String>() {
            @Override
            public String read() throws Exception{
                if (cnt < 10) {
                    cnt++;
                    return "Read OK " + cnt;
                } else {
                    return null;
                }
            }
        };
    }

    @Bean
    public ItemWriter<String> itemWriter(){
        return strList -> {
            strList.forEach(
                    str -> System.out.println(str)
            );
        };
    }

    @Override
    protected Charset getCharset() {
        return StandardCharsets.UTF_8;
    }
}

 

 

 

1. JobParameters 의 값이 같은 값이 들어가게 설정한다면 ?

• could not increment id for batch_job_seq sequence table 에러가 발생합니다.

 

2. test 지만 itemReader 에서 계속 " Read OK " 라는 문자열을 반환하기 때문에 cnt 변수 이용하지 않으면 무한반복입니다.

• DataBase 연결해서 데이터 진짜 조회할 때는 cnt 필요 없습니다.