web应用自动检测客户端浏览器，并转跳到不同页面

通过检测HTTP请求时CGI环境变量，可以获取客户端浏览器请求的一些环境信息

通过调用下面程序中的outputAllCGI方法，可以在控制台输出部分CGI环境变量。

其中包含一个User-Agent变量，包含了请求的操作系统信息，浏览器信息及版本等内容

通过对这些信息的分析，判断请求的客户端是否为手机客户端，自动返回相应的页面

public class UserAgentsUtil {
	
	private static String[] phoneBrowersKey = new String[]{
		"user-agent","noki","eric","wapi","nc21","aur","r380","up.b",
		"winw","upg1","upsi","qwap","jigs","java","alca","nits",
		"not-","my s","wapj","fetc","alav","wapa","ucweb","blackberry",
		"j2me","android","oper","dopod","symbian","iphone","android",
		"mobile","wap","netfront","java","opera mobi","opera mini",
		"ucweb","windows ce","symbian","series","webos","sony",
		"blackberry","dopod","nokia","samsung","palmsource","xda",
		"pieplus","meizu","midp","cldc","motorola","foma","docomo",
		"up.browser","up.link","blazer","helio","hosin","huawei","novarra",
		"coolpad","techfaith","palmsource","alcatel","amoi","ktouch",
		"nexian","ericsson","philips","sagem","wellcom","bunjalloo",
		"maui","smartphone","iemobile","bird","zte-","longcos","pantech",
		"gionee","portalmmm","jig browser","hiptop","benq","haier","^lct",
		"mqqbrowser","320x320","240x320","176x220"
	};

	private static String phoneBrowerUrl = "wap/index.jsp";
	private static String computerBrowerUrl = "web/index.jsp";
	
	public static void redirectByUserAgents(HttpServletRequest request, 
			HttpServletResponse response) 
	throws IOException {
		String userAgent=request.getHeader("user-agent");
		if (userAgent == null) {
			return ;
		}
		userAgent = userAgent.toLowerCase();
		for (int i=0; i<phoneBrowersKey.length; i++) {
			if (userAgent.indexOf(phoneBrowersKey[i]) != -1) {
				response.sendRedirect(phoneBrowerUrl);
				return;
			}
		}
		response.sendRedirect(computerBrowerUrl);
	}
	
	public static void outputAllCGI(HttpServletRequest request, 
			HttpServletResponse response, HttpServlet servlet) {
		String strEnvs[][] = {
				{ "CONTENT_LENGTH ",
					String.valueOf(request.getContentLength()) },
					{ "CONTENT_TYPE ", request.getContentType() },
					{ "SERVER_PROTOCOL ", request.getProtocol() },
					{ "SERVER_SOFTWARE ", servlet.getServletContext().getServerInfo() },
					{ "REMOTE_ADDR ", request.getRemoteAddr() },
					{ "REMOTE_HOST ", request.getRemoteHost() },
					{ "REMOTE_USER ", request.getRemoteUser() },
					{ "SERVER_NAME ", request.getServerName() },
					{ "SERVER_PORT ", String.valueOf(request.getServerPort()) },
					{ "AUTH_TYPE ", request.getAuthType() },
					{ "REQUEST_METHOD ", request.getMethod() },
					{ "PATH_INFO ", request.getPathInfo() },
					{ "PATH_TRANSLATED ", request.getPathTranslated() },
					{ "QUERY_STRING ", request.getQueryString() },
					{ "REQUEST_URI ", request.getRequestURI() },
					{ "SCRIPT_NAME ", request.getServletPath() },
					{ "DOCUMENT_ROOT ", servlet.getServletContext().getRealPath("/ ") } 
		};
		Enumeration enumNames = request.getHeaderNames();
		while (enumNames.hasMoreElements()) {
			String strName = (String) enumNames.nextElement();
			String strValue = request.getHeader(strName);
			System.out.println(strName + " : " + strValue);
		}
		for (int i=0; i<strEnvs.length; i++) {
			System.out.println(strEnvs[i][0] + " : " + strEnvs[i][1]);
		}
	}
}