Launch Spring Batch Job from Spring Integration

Question

I need to download a file from remote SFTP server and process them using spring batch. I already implemented code using Spring Integration to download files. But I can't launch Spring Batch job from spring integration components. I have following code:

    @Autowired
private JobLauncher jobLauncher;

public String OUTPUT_DIR = "temp_dir";

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

@Value("${sftp.remote.user}")
private String sftpUsername;

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

@Value("${sftp.remote.folder}")
private String sftpFolder;

@Bean
public DefaultSftpSessionFactory sftpSessionFactory() {
    final DefaultSftpSessionFactory factory = new DefaultSftpSessionFactory();
    factory.setHost(sftpRemoteHost);
    factory.setAllowUnknownKeys(true);
    factory.setUser(sftpUsername);
    factory.setPassword(sftpPassword);
    return factory;
}

@Bean
public SftpInboundFileSynchronizer sftpInboundFileSynchronizer() {
    final SftpInboundFileSynchronizer fileSynchronizer = new SftpInboundFileSynchronizer(sftpSessionFactory());
    fileSynchronizer.setDeleteRemoteFiles(false);
    fileSynchronizer.setRemoteDirectory(sftpFolder);
    fileSynchronizer.setFilter(new SftpSimplePatternFileListFilter("*.csv"));
    return fileSynchronizer;
}

@Bean
@InboundChannelAdapter(channel = "sftpChannel", poller = @Poller(fixedDelay = "5000"))
public MessageSource<File> sftpMessageSource() {
    final SftpInboundFileSynchronizingMessageSource source =
            new SftpInboundFileSynchronizingMessageSource(sftpInboundFileSynchronizer());
    source.setLocalDirectory(new File(OUTPUT_DIR));
    source.setAutoCreateLocalDirectory(true);
    source.setLocalFilter(new AcceptOnceFileListFilter<>());
    return source;
}

@Bean
@ServiceActivator(inputChannel = "sftpChannel")
public MessageHandler handler() {
    final FileWritingMessageHandler handler = new FileWritingMessageHandler(new File(OUTPUT_DIR));
    handler.setFileExistsMode(FileExistsMode.REPLACE);
    handler.setExpectReply(true);
    handler.setOutputChannelName("parse-csv-channel");
    return handler;
}

@ServiceActivator(inputChannel = "parse-csv-channel", outputChannel = "job-channel")
public JobLaunchRequest adapt(final File file) throws Exception {
    final JobParameters jobParameters = new JobParametersBuilder().addString(
            "input.file", file.getAbsolutePath()).toJobParameters();
    return new JobLaunchRequest(batchConfiguration.job(), jobParameters);
}

@ServiceActivator(inputChannel = "job-channel", outputChannel = "finish")
public JobLaunchingMessageHandler jobHandler(JobLaunchRequest request) throws JobExecutionException {
    return new JobLaunchingMessageHandler(jobLauncher);//.launch(request);
}

@ServiceActivator(inputChannel = "finish")
public void finish() {
    System.out.println("FINISH");
}

But this does not work (error in last method adapt ), because not bean of type File found. I can't clue this two parts together. How to wire integration and batch processing?

Answer 1

You definitely just have to remove the @Bean annotation from your adapt() method. We need @Bean if we really build MessageHandler bean, for example JobLaunchingMessageHandler to accept that JobLaunchRequest payload: https://docs.spring.io/spring-batch/trunk/reference/html/springBatchIntegration.html#launching-batch-jobs-through-messages .

See more info about Messaging Annotations in the Reference Manual: https://docs.spring.io/spring-integration/docs/4.3.12.RELEASE/reference/html/configuration.html#annotations_on_beans

UPDATE

@Bean
@ServiceActivator(inputChannel = "sftpChannel")
public MessageHandler handler() {
    final FileWritingMessageHandler handler = new FileWritingMessageHandler(new File(OUTPUT_DIR));
    handler.setFileExistsMode(FileExistsMode.REPLACE);
    handler.setExpectReply(true);
    handler.setOutputChannelName("parse-csv-channel");
    return handler;
}

@ServiceActivator(inputChannel = "parse-csv-channel", outputChannel = "job-channel")
public JobLaunchRequest adapt(final File file) throws Exception {
    final JobParameters jobParameters = new JobParametersBuilder().addString(
            "input.file", file.getAbsolutePath()).toJobParameters();
    return new JobLaunchRequest(batchConfiguration.job(), jobParameters);
}

@Bean
@ServiceActivator(inputChannel = "job-channel")
public JobLaunchingGateway jobHandler() {
    JobLaunchingGateway jobLaunchingGateway = new JobLaunchingGateway(jobLauncher);
    jobLaunchingGateway.setOutputChannelName("finish");
    return jobLaunchingGateway;
}