I'm glad 和 I'm happy 有什么区别？如果难以说明的话，请教我一下例句。

I think it's the same meaning, but the usage is different.

You usually use "I'm glad" in response to something, for example:
- I'm glad you came.
- I'm glad that's happening.

"I'm happy" can be used like that ("I'm happy about that"), but it can also stand on its own:
- I'm happy.
- Are you happy?

The difference here is that "Are you happy?" is about everything, life in general, while "Aren't you glad?" would have to have a context that we both understand
"Aren't you glad?" (that we met each other)

I hope that was not confusing.