Spring事务失效的一种原因关于this调用的问题

@Service
public class EmployeeService {
 
    @Autowired
    private EmployeeDao employeeDao;
 
    public void save(){
        try {        
            this.saveEmployee();  //此处this调用不会开启事务，数据会被保存
        }catch (Exception e){
            e.printStackTrace();
        }
    }
    
    @Transactional(propagation = Propagation.PROPAGATION_REQUIRED)
    //此处无论是PROPAGATION_REQUIRED还是PROPAGATION_REQUIRES_NEW，事务均不生效
    public void saveEmployee(){
        Employee employee = new Employee();
        employee.setName("zhangsan");
        employee.setAge("26";
        employeeDao.save(employee);
        throw new RuntimeException();
    }
}

@Transactional() //开启事务
public void save(){
    try {        
        this.saveEmployee();  //这里this调用会使事务失效，数据会被保存
    }catch (Exception e){
        e.printStackTrace();
        throw new RuntimeException();
    }
}

public void save(){
    try {        
        EmployeeService proxy =(EmployeeService) AopContext.currentProxy();
        proxy.saveEmployee();
    }catch (Exception e){
        e.printStackTrace();
    }
}