Hi @jinml, I am not aware of any Julia package to compute the Hankel transform. Of course, you have to discretize the continuous transform to either fully discrete or semi-discrete transforms. What is the exact transform that you would like to compute?
As Sheehan mentioned, I have a paper on a fast algorithm for computing various types of fully discrete Hankel transform. You can find that here: [1501.01652] A fast analysis-based discrete Hankel transform using asymptotic expansions.
The direct summation is a “slow” algorithm (see Section 2.1) that can be implemented in less than an hour, which may be good enough for your purposes. It really depends on what you are after, and your application.