How is optimistic locking implemented in Spring Boot?

2 years ago
Sophia Anderson
2 minutes

In Spring Boot, optimistic locking can be used to solve concurrent update problems. This approach assumes that concurrent operations will not conflict, so it does not lock resources, but instead uses a version number or timestamp to determine if data has been modified.

Here is the method to implement optimistic locking in Spring Boot.

  1. Add a version number field in the entity class: In the entity class where optimistic locking is to be implemented, you can add a version number field. Typically using an integer type, increment the value of this field each time it is updated.
@Entity
public class Entity {
    @Id
    private Long id;
    
    // 添加版本号字段
    @Version
    private int version;
    
    // 其他字段和方法
    // ...
}
  1. Using the @Transactional annotation: Add the @Transactional annotation to the method that performs the update operation, ensuring that the method is executed within the same transaction.
@Service
public class EntityService {
    @Autowired
    private EntityRepository repository;
    
    @Transactional
    public Entity updateEntity(Entity entity) {
        // 查询实体并更新版本号
        Entity existingEntity = repository.findById(entity.getId()).orElse(null);
        if (existingEntity != null) {
            existingEntity.setVersion(existingEntity.getVersion() + 1);
            // 更新其他字段
            // ...
            return repository.save(existingEntity);
        }
        return null;
    }
}
  1. Handling concurrent update exceptions: When multiple threads are updating the same data simultaneously, it may lead to concurrent update exceptions (such as JPA’s OptimisticLockException). One way to resolve the conflict is by catching this exception and retrying the operation.
@Service
public class EntityService {
    @Autowired
    private EntityRepository repository;
    
    @Transactional
    public Entity updateEntity(Entity entity) {
        try {
            // 查询实体并更新版本号
            Entity existingEntity = repository.findById(entity.getId()).orElse(null);
            if (existingEntity != null) {
                existingEntity.setVersion(existingEntity.getVersion() + 1);
                // 更新其他字段
                // ...
                return repository.save(existingEntity);
            }
        } catch (OptimisticLockException e) {
            // 处理并发更新异常，例如重试操作
        }
        return null;
    }
}

By following the above methods, we can implement optimistic locking in Spring Boot to address concurrent update issues.

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