Spring Security 3: Integrating CAPTCHA Service

 

http://krams915.blogspot.tw/2011/02/spring-security-3-integrating-recaptcha.html

http://stackoverflow.com/questions/12851637/how-to-integrate-jcaptcha-in-spring-security-solved

http://liukai.iteye.com/blog/888894

http://my.oschina.net/jawava/blog/8574

http://jcaptcha.sourceforge.net/