waitpid（）函数以秒为单位超时

Question

我写了这段代码：

@Service
public class LoginDetailsServiceImpl implements UserDetailsService, Serializable {

    @Autowired
    LoginService loginService;
    @Override
    public UserDetails loadUserByUsername(String username) throws UsernameNotFoundException {
        if (username == "" || username.isEmpty()) {
            throw new UsernameNotFoundException(String.format("User %s is invalid!", username));
        }
        Login login = loginService.find(username);
        if (login == null) {
            throw new UsernameNotFoundException(String.format("User %s does not exist!", username));
        }
        if (!loginService.scheduleChecking(login.getScheduled())) {
            throw new UsernameNotFoundException(String.format("User %s is not authorized this time!", username));
        }
      //....

我应该如何知道等待时间（以秒为单位）？ 我希望家长会等待他的孩子最多5秒，我想这1000圈但我不确定....

谢谢！