Spring Batch并行作业重复使用相同参数（文件名+UUID）问题排查求助

我现在想为每个文件单独启动一个Spring Batch作业实例，最多同时运行20个。但奇怪的是，作业会重复使用相同的参数（同一个文件名+同一个UUID），明明每个参数应该都是唯一的。想问问大家可能是什么原因导致UUID和文件名被重复使用？

我已经写了一个简化版的代码来复现这个问题，下面是我的实现：

主调用类代码 #

public class Main implements CommandLineRunner {
    private final JobLauncher jobLauncher;
    private final Job jobConfig;
    private int parallelism = 20;

    public static void main(String[] args) {SpringApplication.run(Main.class, args);}

    @Override
    public void run(String... args) throws Exception {
        File[] files = getFiles();

        ExecutorService pool = Executors.newFixedThreadPool(parallelism);
        List<Future<?>> futures = new ArrayList<>(files.length);

        for (int i = 0; i < files.length; i++) {
            final File file = files[i];

            futures.add(pool.submit(() -> {
                try {
                    JobParameters params = new JobParametersBuilder()
                            .addString("fileName", file.getCanonicalPath(), true)
                            .addString("guid", UUID.randomUUID().toString(), true)
                            .toJobParameters();
                    JobExecution exec = jobLauncher.run(jobConfig, params);
                    return exec.getExitStatus();
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }
            }));
        }
        for (Future<?> f : futures) {
            f.get();
        }
        pool.shutdown();
    }

    public static File[]  getFiles() {
        File currentDir = new File("C:\\Code\\spring-batch\\input");
        File[] files = currentDir.listFiles((dir, name) -> name.endsWith(".csv"));
        return files;
    }
}

Spring Batch作业配置类 #

@Configuration
@RequiredArgsConstructor
public class JobConfig {

    @Bean
    public PlatformTransactionManager transactionManager() {
        return new ResourcelessTransactionManager();
    }

    @Bean
    public JobLauncher jobLauncher(JobRepository jobRepository) throws Exception {
        TaskExecutorJobLauncher launcher = new TaskExecutorJobLauncher();
        launcher.setJobRepository(jobRepository);
        launcher.setTaskExecutor(new org.springframework.core.task.SyncTaskExecutor());
        launcher.afterPropertiesSet();
        return launcher;
    }
    @Bean
    public Job simpleJob(JobRepository jobRepository, Step simpleStep) {
        return new JobBuilder("simpleJob", jobRepository)
                .incrementer(new RunIdIncrementer())
                .start(simpleStep)
                .build();
    }

    @Bean
    public Step simpleStep(JobRepository jobRepository,
                           PlatformTransactionManager transactionManager,
                           ItemReader<String> reader,
                           ItemProcessor<String, String> processor,
                           FlatFileItemWriter<String> writer) {

        return new StepBuilder("simpleStep", jobRepository)
                .<String, String>chunk(100, transactionManager)
                .reader(reader)
                .processor(processor)
                .writer(writer)
                .stream(writer)
                .build();
    }

    @Bean
    @StepScope
    public FlatFileItemReader<String> reader(
            @Value("#{jobParameters['fileName']}") String fileName,
            @Value("#{jobParameters['guid']}") String guid) {

        return new FlatFileItemReaderBuilder<String>()
                .name("reader-" + guid)
                .resource(new FileSystemResource(fileName))
                .lineMapper((line, lineNumber) -> line)
                .build();
    }

    @Bean
    public ItemProcessor<String, String> processor() {
        return item -> item.toUpperCase();
    }


    @Bean
    @StepScope
    public FlatFileItemWriter<String> writer(
            @Value("#{jobParameters['fileName']}") String fileName,
            @Value("#{jobParameters['guid']}") String guid) {

        String outputName = "OUTPUT_" + getFileNameWithoutExtension(fileName) + "_" + ".out";

        return new FlatFileItemWriterBuilder<String>()
                .name("writer-" + guid)
                .resource(new FileSystemResource(outputName))
                .lineAggregator(new PassThroughLineAggregator<>())
                .build();
    }

    public static String getFileNameWithoutExtension(String fileName) {
      String filename = java.nio.file.Paths.get(fileName).getFileName().toString();
      int dotIndex = filename.lastIndexOf('.');
      if (dotIndex > 0) {
        return filename.substring(0, dotIndex);
      }
      return fileName;
    }
}

问题现象日志 #

我已经确认getFiles()返回的文件数组里没有重复的文件，但日志里能看到同一个文件名和UUID被多次用于作业启动，比如ex_13.csv对应的UUIDf9c2ecae-f68a-4c79-a5ef-4af7e0f3930c被启动了两次：

2026-02-28T23:15:53.606-05:00  INFO 16316 --- \[ool-2-thread-20\] o.s.b.c.l.s.TaskExecutorJobLauncher      : Job: \[SimpleJob: \[name=simpleJob\]\] launched with the following parameters: \[{JobParameter{name='fileName', value=C:\\Code\\spring-batch\\input\\ex_18.csv, type=class java.lang.String, identifying=true},JobParameter{name='guid', value=78696daa-4df3-473f-87cf-42b9a7dc1169, type=class java.lang.String, identifying=true}}\]

2026-02-28T23:15:53.606-05:00  INFO 16316 --- \[pool-2-thread-4\] o.s.b.c.l.s.TaskExecutorJobLauncher      : Job: \[SimpleJob: \[name=simpleJob\]\] launched with the following parameters: \[{JobParameter{name='fileName', value=C:\\Code\\spring-batch\\input\\ex_12.csv, type=class java.lang.String, identifying=true},JobParameter{name='guid', value=94a99043-91e6-4466-87e1-b70683e0ab5b, type=class java.lang.String, identifying=true}}\]

2026-02-28T23:15:53.606-05:00  INFO 16316 --- \[pool-2-thread-5\] o.s.b.c.l.s.TaskExecutorJobLauncher      : Job: \[SimpleJob: \[name=simpleJob\]\] launched with the following parameters: \[{JobParameter{name='fileName', value=C:\\Code\\spring-batch\\input\\ex_13.csv, type=class java.lang.String, identifying=true},JobParameter{name='guid', value=f9c2ecae-f68a-4c79-a5ef-4af7e0f3930c, type=class java.lang.String, identifying=true}}\]

2026-02-28T23:15:53.606-05:00  INFO 16316 --- \[ool-2-thread-15\] o.s.b.c.l.s.TaskExecutorJobLauncher      : Job: \[SimpleJob: \[name=simpleJob\]\] launched with the following parameters: \[{JobParameter{name='fileName', value=C:\\Code\\spring-batch\\input\\ex_13.csv, type=class java.lang.String, identifying=true},JobParameter{name='guid', value=f9c2ecae-f68a-4c79-a5ef-4af7e0f3930c, type=class java.lang.String, identifying=true}}\]

2026-02-28T23:15:53.606-05:00  INFO 16316 --- \[pool-2-thread-1\] o.s.b.c.l.s.TaskExecutorJobLauncher      : Job: \[SimpleJob: \[name=simpleJob\]\] launched with the following parameters: \[{JobParameter{name='fileName', value=C:\\Code\\spring-batch\\input\\ex_1.csv, type=class java.lang.String, identifying=true},JobParameter{name='guid', value=1c21c4a5-4956-4fcf-8cce-868ab1bf78cb, type=class java.lang.String, identifying=true}}\]

2026-02-28T23:15:53.606-05:00  INFO 16316 --- \[pool-2-thread-8\] o.s.b.c.l.s.TaskExecutorJobLauncher      : Job: \[SimpleJob: \[name=simpleJob\]\] launched with the following parameters: \[{JobParameter{name='fileName', value=C:\\Code\\spring-batch\\input\\ex_16.csv, type=class java.lang.String, identifying=true},JobParameter{name='guid', value=27042f9d-f963-4d96-ad6e-b5dabe18ad2e, type=class java.lang.String, identifying=true}}\]

2026-02-28T23:15:53.606-05:00  INFO 16316 --- \[pool-2-thread-7\] o.s.b.c.l.s.TaskExecutorJobLauncher      : Job: \[SimpleJob: \[name=simpleJob\]\] launched with the following parameters: \[{JobParameter{name='fileName', value=C:\\Code\\spring-batch\\input\\ex_15.csv, type=class java.lang.String, identifying=true},JobParameter{name='guid', value=ef576a4e-d225-4eb2-91a4-b3fb1d8b562d, type=class java.lang.String, identifying=true}}\]

2026-02-28T23:15:53.606-05:00  INFO 16316 --- \[pool-2-thread-3\] o.s.b.c.l.s.TaskExecutorJobLauncher      : Job: \[SimpleJob: \[name=simpleJob\]\] launched with the following parameters: \[{JobParameter{name='fileName', value=C:\\Code\\spring-batch\\input\\ex_11.csv, type=class java.lang.String, identifying=true},JobParameter{name='guid', value=1b596d93-4311-44e7-9251-84f8eaa9ba21, type=class java.lang.String, identifying=true}}\]

2026-02-28T23:15:53.606-05:00  INFO 16316 --- \[ool-2-thread-13\] o.s.b.c.l.s.TaskExecutorJobLauncher      : Job: \[SimpleJob: \[name=simpleJob\]\] launched with the following parameters: \[{JobParameter{name='fileName', value=C:\\Code\\spring-batch\\input\\ex_20.csv, type=class java.lang.String, identifying=true},JobParameter{name='guid', value=18bde259-67ea-4c0d-a20d-3c82b654019b, type=class java.lang.String, identifying=true}}\]

2026-02-28T23:15:53.606-05:00  INFO 16316 --- \[ool-2-thread-18\] o.s.b.c.l.s.TaskExecutorJobLauncher      : Job: \[SimpleJob: \[name=simpleJob\]\] launched with the following parameters: \[{JobParameter{name='fileName', value=C:\\Code\\spring-batch\\input\\ex_7.csv, type=class java.lang.String, identifying=true},JobParameter{name='guid', value=e8885719-be1e-4190-996b-011d77cc015b, type=class java.lang.String, identifying=true}}\]

备注：内容来源于stack exchange，提问作者oe a