一个非常简单实用的检查用户浏览器是否支持cookie的servlet，不支持则给出输出提示。
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
public class CheckCookieServlet extends HttpServlet {
/**Process the HTTP Get request*/
public void doGet(HttpServletRequest request, HttpServletResponse response) throws
ServletException, IOException {
response.setContentType("text/html");
PrintWriter out = response.getWriter();
if (request.getParameter("flag")==null) {
// the first request
Cookie cookie = new Cookie("browserSetting", "on");
response.addCookie(cookie);
String nextUrl = request.getRequestURI() + "?flag=1";
out.println("<META HTTP-EQUIV=Refresh CONTENT=0;URL="+ nextUrl +">");
}
else {
// the second request
Cookie[] cookies = request.getCookies();
if (cookies!=null) {
int length = cookies.length;
boolean cookieFound = false;
for (int i=0; i<length; i++) {
Cookie cookie = cookies[i];
if (cookie.getName().equals("browserSetting") &&
cookie.getValue().equals("on")) {
cookieFound = true;
break;
}
}
if (cookieFound) {
out.println("Your browser's cookie setting is on.");
}
else {
out.println("Your browser does not support cookies or" +
" the cookie setting is off.");
}
}
}
/**Process the HTTP Post request*/
public void doPost(HttpServletRequest request, HttpServletResponse
response) throws ServletException, IOException {
doGet(request, response);
}
}