String agent = request.getHeader("User-Agent").toLowerCase();
Pattern pattern = Pattern.compile("msie (\\d+)");
Matcher matcher = pattern.matcher(agent);
if(matcher.find()){
int version = Integer.parseInt(matcher.group(1));
if(version < 9){
//IE9以下版本
}
}
以上一判断lt IE9为例
原文：http://www.cnblogs.com/rubekid/p/4887189.html