Spring Batch — Upload Files to SFTP Server (Complete Guide)

Spring Batch — Upload Files to SFTP Server (Complete Guide)

Uploading files to an SFTP server is a very common enterprise batch requirement — daily reports, partner file exchanges, settlement files, and archival data. In this guide, you’ll learn how to implement a production-ready SFTP file upload job using Spring Batch and Spring Integration SFTP.

📺 Video walkthrough: If you prefer learning visually, watch the full implementation explained step by step on YouTube:
👉 Spring Batch SFTP File Upload – Complete Tutorial

💡 Practice Tip: You can create a free SFTP server for testing and practice using https://sftpcloud.io/tools/free-sftp-server. This is perfect for local development and demos without setting up your own SFTP infrastructure.

Why use Tasklet for SFTP uploads?

  • SFTP uploads are usually file-oriented, not record-oriented
  • Tasklets provide full control over file existence, naming, and transfer logic
  • Simpler restart semantics compared to chunk-based processing
  • Ideal for single or small batches of files

Maven dependencies

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-batch</artifactId>
</dependency>

<dependency>
  <groupId>org.springframework.integration</groupId>
  <artifactId>spring-integration-sftp</artifactId>
</dependency>

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-web</artifactId>
</dependency>

application.properties

spring.application.name=spring-batch-sftp-upload

spring.datasource.url=jdbc:oracle:thin:@localhost:1521/XEPDB1
spring.datasource.username=dbadmin
spring.datasource.password=dbadmin1
spring.datasource.driver-class-name=oracle.jdbc.OracleDriver

spring.batch.job.enabled=false

sftp.host=eu-central-1.sftpcloud.io
sftp.port=22
sftp.username=your-username
sftp.password=your-password
sftp.remote-dir=/pub/example/

SFTP configuration

Spring Integration provides DefaultSftpSessionFactory and SftpRemoteFileTemplate to interact with an SFTP server. 

@Configuration
public class SftpConfig {

  @Value("${sftp.host}")
  private String host;

  @Value("${sftp.port}")
  private int port;

  @Value("${sftp.username}")
  private String username;

  @Value("${sftp.password}")
  private String password;

  @Bean
  public DefaultSftpSessionFactory defaultSftpSessionFactory() {
    DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory();
    factory.setHost(host);
    factory.setPort(port);
    factory.setUser(username);
    factory.setPassword(password);
    factory.setAllowUnknownKeys(true);
    return factory;
  }

  @Bean
  public SftpRemoteFileTemplate sftpRemoteFileTemplate() {
    return new SftpRemoteFileTemplate(defaultSftpSessionFactory());
  }
}

Spring Batch Job configuration

This job uses a single tasklet-based step that uploads a file to the SFTP server. 

@Configuration
public class SpringBatchConfig {

  @Bean
  public Step sftpUploadStep(JobRepository jobRepository,
                             PlatformTransactionManager transactionManager,
                             SftpUploadTasklet tasklet) {
    return new StepBuilder("sftpUploadStep", jobRepository)
      .tasklet(tasklet, transactionManager)
      .build();
  }

  @Bean
  public Job dailyFileJob(JobRepository jobRepository,
                          Step sftpUploadStep) {
    return new JobBuilder("dailyFileJob", jobRepository)
      .start(sftpUploadStep)
      .build();
  }
}

SFTP Upload Tasklet

The tasklet validates file existence, ensures the remote directory exists, and uploads the file using an SFTP session. 

@Component
public class SftpUploadTasklet implements Tasklet {

  @Autowired
  private SftpRemoteFileTemplate sftpRemoteFileTemplate;

  @Override
  public RepeatStatus execute(StepContribution contribution,
                              ChunkContext chunkContext) throws Exception {

    File file = new File("F:/youtube-videos/LikeSubscribe.jpg");

    if (!file.exists()) {
      throw new RuntimeException("File does not exist");
    }

    sftpRemoteFileTemplate.execute(session -> {

      String remoteDir = "/pub/example";
      if (!session.exists(remoteDir)) {
        session.mkdir(remoteDir);
      }

      try (InputStream is = new FileInputStream(file)) {
        session.write(is, remoteDir + "/" + file.getName());
      }
      return null;
    });

    return RepeatStatus.FINISHED;
  }
}

REST API to trigger job

@RestController
@RequestMapping("/api/batch")
public class JobController {

  private final JobLauncher jobLauncher;
  private final Job dailyFileJob;

  public JobController(JobLauncher jobLauncher, Job dailyFileJob) {
    this.jobLauncher = jobLauncher;
    this.dailyFileJob = dailyFileJob;
  }

  @GetMapping("/trigger-sftp")
  public ResponseEntity<String> triggerSftpJob() {
    try {
      JobParameters params = new JobParametersBuilder()
        .addLong("startAt", System.currentTimeMillis())
        .toJobParameters();

      jobLauncher.run(dailyFileJob, params);
      return ResponseEntity.ok("SFTP Upload Job triggered successfully.");
    } catch (Exception e) {
      return ResponseEntity.internalServerError()
        .body("Job failed: " + e.getMessage());
    }
  }
}

Transactional behavior & restartability

  • If the tasklet fails, the step is marked as FAILED
  • Restarting the job re-executes the upload logic
  • Ensure idempotency to avoid duplicate uploads

Production best practices

  • Use temporary filenames and rename after upload
  • Enable retries for transient network failures
  • Prefer key-based authentication over passwords
  • Log upload metadata (file name, size, timestamp)
  • Validate file checksum after upload if required

FAQ

  • Why not use ItemWriter? Tasklets are simpler for file transfers.
  • Can I upload multiple files? Yes — iterate over a directory inside the tasklet.
  • Is SftpRemoteFileTemplate thread-safe? Yes, when used per execution.

Conclusion

Using Spring Batch with Spring Integration SFTP provides a clean and reliable way to upload files to external systems. Tasklet-based jobs are simple, flexible, and production-friendly for file transfer use cases.

🎥 Don’t forget to watch the full YouTube walkthrough:
Spring Batch SFTP File Upload – Step-by-Step Video Guide

🧱 Spring Batch Core Components

Understand how ItemReader, ItemProcessor, and ItemWriter work together when exporting data to CSV files.

🔄 Spring Batch ItemProcessor Example

Apply transformation and formatting logic before writing records into CSV output files.

🔁 CSV to Database with Spring Batch

Compare inbound (CSV → DB) and outbound (DB → CSV) batch processing patterns.

🚫 Skip Policy & Error Handling

Handle write failures and formatting errors gracefully while exporting large datasets.

🔀 Conditional Flow in Spring Batch Jobs

Control job execution paths based on CSV generation success or failure.

🧵 Multithreaded Step in Spring Batch

Improve export performance by parallelizing data processing and CSV writing steps.