このバージョンはまだ開発中であり、まだ安定しているとは見なされていません。最新の安定バージョンについては、Spring Batch ドキュメント 5.2.4 を使用してください！

Spring Batch 6 の新機能

依存関係のアップグレード

このメジャーリリースでは、Spring の依存関係が次のバージョンにアップグレードされます。

  • Spring Framework 7.0

  • Spring Integration 7.0

  • Spring Data 4.0

  • Spring LDAP 4.0

  • Spring AMQP 4.0

  • Spring Kafka 4.0

  • Micrometer 1.16

バッチインフラストラクチャ構成の改善

バッチインフラストラクチャ構成用の新しいアノテーションとクラス

v6 より前では、@EnableBatchProcessing アノテーションは JDBC ベースのインフラストラクチャに紐付けられていました。これはもはや当てはまりません。基盤となるジョブリポジトリを設定するための 2 つの新しいアノテーション、@EnableJdbcJobRepository と @EnableMongoJobRepository が導入されました。

v6 以降、@EnableBatchProcessing ではバッチインフラストラクチャの共通属性を構成できるようになり、新しい専用アノテーションを使用してストア固有の属性を指定できるようになりました。

これらのアノテーションの使用方法の例を次に示します。

@EnableBatchProcessing(taskExecutorRef = "batchTaskExecutor")
@EnableJdbcJobRepository(dataSourceRef = "batchDataSource", transactionManagerRef = "batchTransactionManager")
class MyJobConfiguration {

	@Bean
	public Job job(JobRepository jobRepository) {
		return new JobBuilder("job", jobRepository)
                    // job flow omitted
                    .build();
	}
}

同様に、DefaultBatchConfiguration に基づくプログラムモデルも更新され、ストア固有の属性を定義するための 2 つの新しい設定クラス（JdbcDefaultBatchConfiguration と MongoDefaultBatchConfiguration）が導入されました。これらのクラスを使用することで、各ジョブリポジトリやその他のバッチインフラストラクチャ Bean の特定の属性をプログラム的に設定できます。

デフォルトでリソースレスのバッチインフラストラクチャ

DefaultBatchConfiguration クラスが更新され、デフォルトで「リソースレス」なバッチインフラストラクチャ（v5.2 で導入された ResourcelessJobRepository 実装に基づく）が提供されるようになりました。これにより、以前はバッチメタデータの保存に必要だったジョブリポジトリ用のインメモリデータベース（H2 や HSQLDB など）が不要になりました。

さらに、ResourcelessJobRepository はデータベース接続やトランザクションを必要としないため、この変更により、メタデータが使用されていない場合のバッチアプリケーションのデフォルトのパフォーマンスが向上します。

最後に、この変更により、メタデータの保存にメモリ内データベースが不要になるため、バッチアプリケーションのメモリフットプリントを削減できます。

バッチインフラストラクチャ構成の簡素化

v6 より前では、複雑な Spring Batch アプリケーションの典型的な設定は非常に複雑で、JobRepository、JobLauncher、JobExplorer、JobOperator、JobRegistry、JobRegistrySmartInitializingSingleton など多くの Bean が必要でした。そのため、たとえば JobRepository と JobExplorer の両方で同じ実行コンテキストシリアライザーを設定するなど、多くの設定コードが必要でした。

このリリースでは、バッチインフラストラクチャの構成を簡素化するためにいくつかの変更が加えられました。

  • JobRepository は JobExplorer インターフェースを継承するため、別途 JobExplorer Bean を定義する必要はありません。

  • JobOperator は JobLauncher インターフェースを継承するため、別途 JobLauncher Bean を定義する必要はありません。

  • JobRegistry はオプションになり、ジョブを自動的に登録できるほどスマートになったため、別途 JobRegistrySmartInitializingSingleton Bean を定義する必要はありません。

  • The transaction manager is now optional, and a default ResourcelessTransactionManager is used if none is provided.

This reduces the number of beans required for a typical batch application and simplifies the configuration code.

チャンク指向処理モデルの新しい実装

This is not a new feature, but rather a new implementation of the chunk-oriented processing model. This new implementation was introduced as an experimental addition in version 5.1, and is now available as stable in version 6.0.

The new implementation is provided in the ChunkOrientedStep class, which is a replacement for the ChunkOrientedTasklet / TaskletStep classes.

Here is an example of how to define a ChunkOrientedStep by using its builder:

@Bean
public Step chunkOrientedStep(JobRepository jobRepository, JdbcTransactionManager transactionManager,
        ItemReader<Person> itemReader, ItemProcessor<Person, Person> itemProcessor, ItemWriter<Person> itemWriter) {
    int chunkSize = 100;
    return new ChunkOrientedStepBuilder<Person, Person>(jobRepository, transactionManager, chunkSize)
        .reader(itemReader)
        .processor(itemProcessor)
        .writer(itemWriter)
        .build();
}

Moreover, fault-tolerance features were adapted as follows:

  • The retry feature is now based on the retry functionality introduced in Spring Framework 7 , instead of the previous Spring Retry library

  • The skip feature has been slightly adapted to the new implementation, which is now only based entirely on the SkipPolicy interface

Here is a quick example of how to use the retry and skip features with the new ChunkOrientedStep:

@Bean
public Step faulTolerantChunkOrientedStep(JobRepository jobRepository, JdbcTransactionManager transactionManager,
        ItemReader<Person> itemReader, ItemProcessor<Person, Person> itemProcessor, ItemWriter<Person> itemWriter) {

    // retry policy configuration
    int maxAttempts = 10;
    var retrybaleExceptions = Set.of(TransientException.class);
    RetryPolicy retryPolicy = RetryPolicy.builder()
        .maxAttempts(maxAttempts)
        .includes(retrybaleExceptions)
        .build();

    // skip policy configuration
    int skipLimit = 50;
    var skippableExceptions = Set.of(FlatFileParseException.class);
    SkipPolicy skipPolicy = new LimitCheckingExceptionHierarchySkipPolicy(skippableExceptions, skipLimit);

    // step configuration
    int chunkSize = 100;
    return new ChunkOrientedStepBuilder<Person, Person>(jobRepository, transactionManager, chunkSize)
        .reader(itemReader)
        .processor(itemProcessor)
        .writer(itemWriter)
        .faultTolerant()
        .retryPolicy(retryPolicy)
        .skipPolicy(skipPolicy)
        .build();
}

Please refer to the migration guide [GitHub] (英語) for more details on how to migrate from the previous implementation to the new one.

新しい並行性モデル

Prior to this release, the concurrency model based on the "parallel iteration" concept required a lot of state synchronization at different levels and had several limitations related to throttling and backpressure leading to confusing transaction semantics and poor performance.

This release revisits that model and comes with a new, simplified approach to concurrency based on the producer-consumer pattern. A concurrent chunk-oriented step now uses a bounded internal queue between the producer thread and consumer threads. Items are put in the queue as soon as they are ready to be processed, and consumer threads take items from the queue as soon as they are available for processing. Once a chunk is ready to be written, the producer thread pauses until the chunk is written, and then resumes producing items.

This new model is more efficient, easier to understand and provides better performance for concurrent executions.

新しいコマンドライン演算子

Spring Batch provided a CommandLineJobRunner since version 1. While this runner served its purpose well over the years, it started to show some limitations when it comes to extensibility and customisation. Many issues like static initialisation, non-standard way of handling options and parameters, lack of extensibility, etc have been reported.

Moreover, all these issues made it impossible to reuse that runner in Spring Boot, which resulted in duplicate code in both projects as well behaviour divergence (like job parameters incrementer behaviour differences) that is confusing to many users.

This release introduces a modern version of CommandLineJobRunner, named CommandLineJobOperator, that allows you to operate batch jobs from the command line (start, stop, restart and so on) and that is customisable, extensible and updated to the new changes introduced in Spring Batch 6.

失敗したジョブ実行を回復する機能

Prior to this release, if a job execution fails abruptly, it was not possible to recover it without a manual database update. This was error-prone and not consistent across different job repositories (as it required a few SQL statements for JDBC databases and some custom statements for NoSQL stores).

This release introduces a new method named recover in the JobOperator interface that allows you to recover failed job executions consistently across all job repositories.

あらゆるステップを停止する機能

As of v5.2, it is only possible to externally stop Tasklet steps through JobOperator#stop. If a custom Step implementation wants to handle external stop signals, it just can’t.

This release adds a new interface, named StoppableStep, that extends Step and which can be implemented by any step that is able to handle stop signals.

Graceful Shutdown support

Spring Batch 6.0 introduces support for graceful shutdown of batch jobs. This feature allows you to stop a running job execution in a controlled manner, ensuring that interruption signals are correctly sent to running steps.

When a graceful shutdown is initiated, the job execution will stop currently active steps and updates the job repository with a consistent state that enables restartability. Once running steps have finished, the job execution will be marked as stopped, and any necessary cleanup operations will be performed.

Observability with the Java Flight Recorder (JFR)

In addition to the existing Micrometer metrics, Spring Batch 6.0 introduces support for the Java Flight Recorder (JFR) to provide enhanced observability capabilities.

JFR is a powerful profiling and event collection framework built into the Java Virtual Machine (JVM). It allows you to capture detailed information about the runtime behavior of your applications with minimal performance overhead.

This release introduces several JFR events to monitor key aspects of a batch job execution, including job and step executions, item reads and writes, as well as transaction boundaries.

JSpecify による null 安全性アノテーション

Spring Batch 6.0 API are now annotated with JSpecify (英語) annotations to provide better null-safety guarantees and improve code quality.

Local chunking support

Similar to remote chunking, local chunking is a new feature that allows you to process chunks of items in parallel, locally within the same JVM using multiple threads. This is particularly useful when you have a large number of items to process and want to take advantage of multi-core processors. With local chunking, you can configure a chunk-oriented step to use multiple threads to process chunks of items concurrently. Each thread will read, process and write its own chunk of items independently, while the step will manage the overall execution and commit the results.

SEDA style with Spring Integration message channels

In Spring Batch 5.2, we introduced the concept of SEDA (Staged Event-Driven Architecture) style processing using local threads with the BlockingQueueItemReader and BlockingQueueItemWriter components. Building on that foundation, Spring Batch 6.0 introduces support for SEDA style processing at scale using Spring Integration messaging channels. This allows you to decouple the different stages of a batch job and process them asynchronously using message channels. By leveraging Spring Integration, you can easily configure and manage the messaging channels, as well as take advantage of features like message transformation, filtering, and routing.

Jackson 3 サポート

Spring Batch 6.0 has been upgraded to support Jackson 3.x for JSON processing. This upgrade ensures compatibility with the latest features and improvements in the Jackson library, while also providing better performance and security. All JSON-related components in Spring Batch, such as the JsonItemReader and JsonFileItemWriter, as well as the JacksonExecutionContextStringSerializer have been updated to use Jackson 3.x by default.

The support for Jackson 2.x has been deprecated and will be removed in a future release. If you are currently using Jackson 2.x in your Spring Batch applications, it is recommended to upgrade to Jackson 3.x to take advantage of the latest features and improvements.

Remote step support

This release introduces support for remote step executions, allowing you to execute steps of a batch job on remote machines or clusters. This feature is particularly useful for large-scale batch processing scenarios where you want to distribute the workload across multiple nodes to improve performance and scalability. Remote step execution is facilitated through the use of Spring Integration messaging channels, which enable communication between the local job execution environment and the remote step executors.

廃止と削減

As with any major release, some features have been deprecated or removed in Spring Batch 6.0. The following changes are worth noting:

  • All deprecated API and features from previous versions have been removed

  • Modular configuration through @EnableBatchProcessing(modular = true) has been deprecated

  • Several API have been deprecated in this version, in order to simplify the core API and reduce its scope

  • Deprecate JUnit 4 support in the spring-batch-test module

  • Deprecate Jackson 2 support

  • Deprecate XML configuration through the batch:…​ namespace

Fore more details, please refer to the migration guide [GitHub] (英語) .