// Import required packages import javax.servlet.*; import javax.servlet.http.*; import java.io.*; import java.util.*; public class HeaderServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // Get all headers EnumerationheaderNames = request.getHeaderNames(); // Print all headers while (headerNames.hasMoreElements()) { String headerName = (String) headerNames.nextElement(); String headerValue = request.getHeader(headerName); System.out.println(headerName + " = " + headerValue); } } }
// Import required packages import javax.servlet.*; import javax.servlet.http.*; import java.io.*; import java.util.*; import java.text.*; public class UserAgentHeaderServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // Get user-agent header String userAgent = request.getHeader("User-Agent"); // Check if user is using mobile device boolean isMobile; if(userAgent.contains("Mobile")) { isMobile = true; } else { isMobile = false; } // Print result PrintWriter out = response.getWriter(); out.println("User-Agent: " + userAgent); out.println("Is Mobile: " + isMobile); } }This example retrieves the user-agent header from the request and checks if the user is using a mobile device. It then prints the result. The javax.servlet.http.HttpServletRequest.getHeaders() method belongs to the javax.servlet.http package library.