java - 在 Spring 批处理中重试阅读器

Question

我编写了一个 Spring Batch 应用程序，项目读取器抛出异常。如何重试项目阅读器？我已经添加了应用程序类上的 @EnableRetry ，下面是阅读器代码

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

下面是读者类

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;
  }
}

但即使在此之后，读取器也不会重试并且作业失败

Answer 1

您正在 bean 定义方法上添加 @Retryable。此方法仅在配置时由 Spring 调用来创建 bean 实例，并且不太可能失败。

您应该在阅读器的 read 方法上添加注释，该方法在运行时步骤运行时调用，并可能引发异常:

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