问题
what's the proper way to capture biometric information (pressure, speed...) by signing with a stylus on a canvas developed in a JSP web Page
回答1:
Alright, since no one else has attempted to answer this question, I shall elaborate on my comment and opefully it will serve as an answer to others as well.
First, Java Server Pages (JSP) is a server-side language. It is meant to run on the web-server and not on the user's browser. The same goes for other server-side languages like PHP and ASP.
So a server-side language is not able to directly interact with devices (keyboard, scanners, cameras, etc). Only when the data is submitted by the browser or client program, the server receives it for processing.
For a device to receive input, there are two key pieces of software needed.
- The device driver: which must be installed on the user's machine
- The application program to capture inputs and do any processing.
If either one is missing, the device cannot function. And then there's another issues. Depending on the device, there's various feedback from the driver/API that should go back to the application that reads it. For example, if a fingerprint scan was not very successful for some reason, the scanner should tell this to the user. So again, there's the need for interactivity between the device and the user's application.
Thus, using any server-side language is out of the question for such applicatoins.
Now, in order to make this possible, you may use a client-side program. Here are some options.
- A native application in VB, C/C++, Pascal or other language. If this is an option, the user must install this application on their computer.
- A browser-based program. This can be a program created using JAVA (not Javascript or JSP), or ActiveX component. ActiveX is largely OS/browser dependent. And the TRUTH is that even Java is not truly platform independent when it comes to different operating systems. There are some technical differences that you'll need to look into. But for the most part of interactivity and high-level operations, yes, Java is more platform-independent than the others. But on a personal note, Java is my worst language. I try not to use it anywhere anymore. That's a different story.
In both options above, every client machine must have their own proprietory drivers and often some sort of API for browser integration.
A year or so ago, I had to program a Bio-Mini fingerprint scanner using VB. It was all sweet in the beginning. Then due to the restrictions of networkability and concurrent usage, the drivers/SDK could not take the load and things were going wrong. By the way, the drivers/SDK were meant for MS-Access. Knowing that the DB was the problem, I started to port this to MySQL. And it was a severe climb from there. I had to do a near-rewrite of the SDK for capturing and comparing data using arrays in VB. And to make things worst, the device was changed and things went wrong again. But do note that the new device was from the same manufacturer.
So keep in mind that even a simple change like that can cause a problem.
来源：https://stackoverflow.com/questions/17886411/how-to-capture-biometric-information-on-a-webpage-by-using-java