如何使用JSF获取用户的浏览器ID？

Question

Is it possible to get the user's browser id number using JSF? I use JBoss 7 for application server.

Answer 1

The browser's user agent string is available as HTTP request header with the name User-Agent . The request headers are in JSF available by ExternalContext#getRequestHeaderMap() :

ExternalContext externalContext = FacesContext.getCurrentInstance().getExternalContext();
String userAgent = externalContext.getRequestHeaderMap().get("User-Agent");

No need to haul the raw Servlet API from under the JSF hoods. Always look at the javadoc of ExternalContext first whenever you need to have access to the HTTP servlet request or response.

Keep in mind that request headers (as everything else in a HTTP request) are fully controllable by the enduser. So never assume the information to be correct and valid. Use it for statistics only. If you need to do feature detection, strongly prefer client side languages like JavaScript and/or CSS if possible. They can do that much more reliably.

Answer 2

您可以从request读取user-agent标头，以获取有关浏览器的详细信息

((HttpServletRequest)FacesContext.getCurrentInstance().getExternalContext().getRequest()).getHeaders();