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The Java Developers Almanac 1.4Order this book from Amazon. |
e1043. Getting a Request Header in a ServletThis example demonstrates how to get the value of a request header in either a GET or POST request.// See also e1035 The Quintessential Servlet // This method is called by the servlet container to process a GET request. public void doGet(HttpServletRequest req, HttpServletResponse resp) throws IOException { doGetOrPost(req, resp); } // This method is called by the servlet container to process a POST request. public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException { doGetOrPost(req, resp); } // This method handles both GET and POST requests. private void doGetOrPost(HttpServletRequest req, HttpServletResponse resp) throws IOException { PrintWriter out = resp.getWriter(); resp.setContentType("text/plain"); // Get the value of a request header; the name is case-insensitive String name = "user-agent"; String value = req.getHeader(name); if (value == null) { // The request header was not present } // Get all request headers Enumeration enum = req.getHeaderNames(); for (; enum.hasMoreElements(); ) { // Get the name of the request header name = (String)enum.nextElement(); out.println(name); // Get a value of the request header value = req.getHeader(name); // If the request header can appear more than once, get all values Enumeration valuesEnum = req.getHeaders(name); for (; valuesEnum.hasMoreElements(); ) { // Get a value of the request header value = (String)valuesEnum.nextElement(); out.println(" "+value); } } out.close(); }
e1041. Preventing Concurrent Requests to a Servlet e1042. Getting the Requesting URL in a Servlet e1044. Processing a HEAD Request in a Servlet e1045. Getting the Client's Address in a Servlet © 2002 Addison-Wesley. |