  Event spectra of the neutrino-$^{16}$O charged-current reactions in
Super-Kamiokande are evaluated for a future supernova neutrino burst. Since
these channels are expected to be useful for diagnosing a neutrino spectrum
with high average energy, the evaluations are performed not only for an
ordinary supernova neutrino model but also for a model of neutrino emission
from a black-hole-forming collapse. Using shell model results, whose excitation
energies are consistent with the experimental data, the cross sections of the
$^{16}$O($\nu_e, e^-$)X and $^{16}$O($\bar\nu_e, e^+$)X reactions for each
nuclear state with a different excitation energy are employed in this study. It
is found that, owing to the components of the reaction with higher excitation
energy, the event spectrum becomes 4-7 MeV softer than that in the case without
considering the excitation energies. In addition, a simplified approach to
evaluate the event spectra is proposed for convenience and its validity is
examined.
