セッションとcoookie

package pack;package pack;import java.io.IOException;import java.io.PrintWriter;
import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;
@WebServlet(name = "SessionCertain", urlPatterns = { "/SessionCertain" })
public class SessionCertain extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException{
response.setContentType("text/html; charset=Shift_JIS"); PrintWriter out = response.getWriter();
HttpSession session = request.getSession(false);
out.println("<html>"); out.println("<head>"); out.println("<title>セッションテスト</title>"); out.println("</head>"); out.println("<body>");
if (session == null){ out.println("セッションを開始します"); session = request.getSession(true); }
String session_id = session.getId();
out.println(""); out.println("セッションIDは" + session_id + "です "); out.println("");
Cookie cookie[] = request.getCookies();
out.println(""); if (cookie != null){ out.println("クライアントから送信されたクッキーを表示します "); for (int i = 0 ; i < cookie.length ; i++){ out.println(cookie[i].getName() + " = " + cookie[i].getValue() + " "); } }else{ out.println("クッキーはクライアントから送信されていません "); } out.println("");
out.println("</body>"); out.println("</html>"); } }