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]);}}
}