Why the @Transactional doesn't work in a web project which is based on SpringBoot?

I did a web project by ussing SpringBoot.No matter how many times or how hard I try.It still doesn’t rollback.Is there anyone could help me.Thank you so much!
Here are the codes.

//a Controller
@PostMapping(value = "/savePlan")
public R saveYearPlan(@RequestBody ProductPlanOutputMain productPlanOutputMain){
        
    return planService.saveOrUpdatePlanBatch(productPlanOutputMain);
        
}

@Service
public class PlanServiceImpl implements PlanService {
    
    
    @Override
    public R saveOrUpdatePlanBatch(ProductPlanOutputMain productPlanOutputMain) {
        return saveOrUpdateDailyPlan(productPlanOutputMain);
    }

    
    @Transactional(rollbackFor = Exception.class)
    public R saveOrUpdateDailyPlan(ProductPlanOutputMain productPlanOutputMain){
        
        //Save data to DB.
        productPlanOutputMainService.saveOrUpdatePlan(productPlanOutputMain);

        //test rollback
        threw new RuntimeException("something wrong");

    }

}

I’ve tried many times.

>Solution :

@Transactional won’t work for a method called from the same class. Put it in a separate service class.