Retrying reader in spring Batch

Question

I have written a spring batch application and item reader is throwing exception. How do I retry item reader? I h ave added @EnableRetry on application class and below is the reader code

@Bean
  @Retryable(include = { RuntimeException.class }, maxAttempts = 1000, backoff = @Backoff(delay = 0))
  public ItemReader<Student> reader() {
    return new InMemoryStudentReader();
  }

Below is the reader class

public class InMemoryStudentReader implements ItemReader<Student> {

  @Autowired
  private JdbcTemplate jdbcTemplate;

  private int nextStudentIndex;
  private List<Student> studentData;

  public InMemoryStudentReader() {
    initialize();
  }


  private void initialize() {
    Student s1 = new Student(1, "ABC");
    Student s2 = new Student(2, "DEF");
    Student s3 = new Student(3, "GHI");

    studentData = Collections.unmodifiableList(Arrays.asList(s1, s2,s3));
    nextStudentIndex = 0;
  }

  @Override
  public Student read() throws Exception {
    Student nextStudent = null;

    if (nextStudentIndex < studentData.size()) {
      int a =jdbcTemplate.queryForObject("SELECT id FROM val LIMIT 1", Integer.class);
      if(a == 2) {
        throw new RuntimeException("Exception");
      }
      nextStudent = studentData.get(nextStudentIndex);
      nextStudentIndex++;
    } else {
      nextStudentIndex = 0;
    }

    return nextStudent;
  }
}

But even after this the reader is not retried and job fails

Do you add `@EnableRetry`? Are you sure you're failing for RuntimeException? [docs](https://www.baeldung.com/spring-retry) — WoAiNii, Apr 26 '20 at 17:53
@WoAiNii I think its not working because of https://stackoverflow.com/questions/38212471/springboot-retryable-not-retrying — Legendary_Hunter, Apr 26 '20 at 18:15
Does this answer your question? [Retry not working with Spring Batch with Java Config](https://stackoverflow.com/questions/56170179/retry-not-working-with-spring-batch-with-java-config) — Mahmoud Ben Hassine, Apr 26 '20 at 18:38
@MahmoudBenHassine I know faultTolerant is not applied to reader but I am specifically specifying Retryable on reader bean. It should be retried then — Legendary_Hunter, Apr 26 '20 at 19:02

score 1 · Accepted Answer · answered Apr 27 '20 at 07:51

1

You are adding @Retryable on a bean definition method. This method is only called at configuration time by Spring to create an instance of your bean and will unlikely fail.

You should be adding the annotation on the read method of your reader which is called at runtime when the step is running and might throw an exception:

@Override
@Retryable(include = { RuntimeException.class }, maxAttempts = 1000, backoff = @Backoff(delay = 0))
public Student read() throws Exception {
   ...
}

answered Apr 27 '20 at 07:51

Mahmoud Ben Hassine

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can we make JpaPagingItemReader retryable: public JpaPagingItemReader reader(EntityManagerFactory entityManagerFactory) { return new JpaPagingItemReaderBuilder() .name("Test") .entityManagerFactory(entityManagerFactory) .queryString("query") .pageSize(chunkSize) .build(); } – Sukh May 16 '23 at 04:43

Retrying reader in spring Batch

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