I'm not sure why this got so many down votes. It is a very valid question. If this site is going to take up a discussion on topics on comparative religion (i.e. whether or not Jesus was a Buddha), there's no reason why questions of comparative philosophy can't also be entertained. In fact, I'd say that this is actually an important question because it really gets at the heart of the difference between Buddhism and Western philosophy.
I don't think you can draw a perfect parallel between Buddhism and Plato Cave, but there are some fleeting similarities specifically between what is written in the Republic and the use of koans in Zen Buddhism. In Plato's cave, we find Socrates advising Glaucon that the most effective form of study "has a power of drawing and converting the mind to the contemplation of true being". Knowledge of the sciences has the double use of being functional (as for the military leader) and revelatory (for the philosopher). It is at once pragmatic and soteriological. For the philosopher, study of a single aspect of reality reveals a kind of universal truth. Socrates for example, uses the perception of fingers giving rise to a conceptualization of unity.
In the sciences, we study one specific aspect of reality. The value in the scientific method is in it's keen ability to narrow the focus of an experiment, be able to control for variables, and draw conclusions. Zen koans are also extremely specific. Koan literally means "public case". Their scope is as narrow as a legal decision. A koan is given to alert the student to a very specific aspect of reality. Just as Socrates uses the external sciences and geometry, the phenomenon addressed by koans can often be a matter of external sense perception. The Buddha Holds Out a Flower, Hsiang-yen's sweeping, and many other koans use an isolated case of sensory perception as a means of revealing something about the nature of reality.
While external nature is revelatory in both systems, it's the difference in approach that really distinguishes Buddhism from the methodology used by Socrates. Over and over again in the Republic, Socrates' philosopher is using his discriminating mind - his reason - as a means of apprehending the truth. He thinks about the ramifications of his subjects. Consider the following passage:
Until the person is able to abstract and define rationally the idea of
good, and unless he can run the gauntlet of all objections, and is
ready to disprove them, not by appeals to opinion, but to absolute
truth, never faltering at any step of the argument --unless he can do
all this, you would say that he knows neither the idea of good nor any
other good; he apprehends only a shadow, if anything at all, which is
given by opinion and not by science; --dreaming and slumbering in this
life, before he is well awake here, he arrives at the world below, and
has his final quietus.
The man liberated from Socrates' cave is a rational being of intellectual understanding. The philosophy that rises out of his study of science lives in the world of conceptualization. Contrast that with the student of Zen. The value of his study isn't based on what Buddha's flower means intellectually, but rather in the actual perception of that flower in a mind marked by emptiness. The student of Zen isn't concerned with the philosophical implications of why Hsiang-yen was liberated when the rock hit the bamboo. A student of Zen, in a state of emptiness, wants to hear the "tock" for themselves. The kind of sensory experience used in Zen can only be had through deep meditation and the emptying the mind of forms.
The western philosophy uses the mind to escape the cave. Zen uses no-mind.