https://stackoverflow.com/questions/51773652/spring-batch-stop-writer-when-reader-return-null https://stackoverflow.com/questions/51780615/how-to-skip-itemwriter-if-readcount-is-zero

MyJob.java

/*
 * Copyright 2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.batch.sample;

import java.util.ArrayList;

import org.springframework.batch.core.Job;
import org.springframework.batch.core.JobExecution;
import org.springframework.batch.core.JobParameters;
import org.springframework.batch.core.JobParametersBuilder;
import org.springframework.batch.core.Step;
import org.springframework.batch.core.configuration.annotation.EnableBatchProcessing;
import org.springframework.batch.core.configuration.annotation.JobBuilderFactory;
import org.springframework.batch.core.configuration.annotation.StepBuilderFactory;
import org.springframework.batch.core.launch.JobLauncher;
import org.springframework.batch.core.step.NoWorkFoundStepExecutionListener;
import org.springframework.batch.item.ItemReader;
import org.springframework.batch.item.file.FlatFileItemWriter;
import org.springframework.batch.item.file.builder.FlatFileItemWriterBuilder;
import org.springframework.batch.item.file.transform.PassThroughLineAggregator;
import org.springframework.batch.item.support.ListItemReader;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.io.FileSystemResource;

@Configuration
@EnableBatchProcessing
public class MyJob {

	@Autowired
	private JobBuilderFactory jobs;

	@Autowired
	private StepBuilderFactory steps;

	@Bean
	public ItemReader<String> itemReader() {
		return new ListItemReader<>(new ArrayList<>());
	}

	@Bean
	public FlatFileItemWriter<String> itemWriter() {
		return
				new FlatFileItemWriterBuilder<String>()
						.name("itemWriter")
						.resource(new FileSystemResource("build/output.txt"))
						.lineAggregator(new PassThroughLineAggregator<>())
//						.shouldDeleteIfEmpty(true) // use this or fail the step with NoWorkFoundStepExecutionListener
						.build();
	}

	@Bean
	public Step step() {
		return steps.get("step")
				.<String, String>chunk(1)
				.reader(itemReader())
				.writer(itemWriter())
				// the following listener sets the exit status of the step to FAILED, but the status will still be completed
				// so by default, any further step will be executed.
				// It is required to use .on("FAILED").fail() to fail the step (and the job) in addition to this listener
				// See BatchStatus vs ExitStatus: https://docs.spring.io/spring-batch/4.0.x/reference/html/step.html#batchStatusVsExitStatus
				.listener(new NoWorkFoundStepExecutionListener())
				.build();
	}

	@Bean
	public Job job() {
		return jobs.get("job")
				.start(step())
				.on("FAILED").fail()
				.build()
				.build();
	}

	public static void main(String[] args) throws Exception {
		ApplicationContext context = new AnnotationConfigApplicationContext(MyJob.class);
		JobLauncher jobLauncher = context.getBean(JobLauncher.class);
		Job job = context.getBean(Job.class);
		JobParameters jobParameters = new JobParametersBuilder()
				.addString("name", "foo")
				.toJobParameters();
		JobExecution jobExecution = jobLauncher.run(job, jobParameters);
		System.out.println(jobExecution.getStepExecutions().iterator().next().getSummary());

	}

}