  The physics potential of detecting $^8$B solar neutrinos will be exploited at
the Jiangmen Underground Neutrino Observatory (JUNO), in a model independent
manner by using three distinct channels of the charged-current (CC),
neutral-current (NC) and elastic scattering (ES) interactions. Due to the
largest-ever mass of $^{13}$C nuclei in the liquid-scintillator detectors and
the {expected} low background level, $^8$B solar neutrinos would be observable
in the CC and NC interactions on $^{13}$C for the first time. By virtue of
optimized event selections and muon veto strategies, backgrounds from the
accidental coincidence, muon-induced isotopes, and external backgrounds can be
greatly suppressed. Excellent signal-to-background ratios can be achieved in
the CC, NC and ES channels to guarantee the $^8$B solar neutrino observation.
From the sensitivity studies performed in this work, we show that JUNO, with
ten years of data, can reach the {1$\sigma$} precision levels of 5%, 8% and 20%
for the $^8$B neutrino flux, $\sin^2\theta_{12}$, and $\Delta m^2_{21}$,
respectively. It would be unique and helpful to probe the details of both solar
physics and neutrino physics. In addition, when combined with SNO, the
world-best precision of 3% is expected for the $^8$B neutrino flux measurement.
