repeatvisitor.java

servlet学习代码

package jsp.servlet.chapter7.cookie;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import jsp.servlet.util.ServletUtil;

@SuppressWarnings("serial")
public class RepeatVisitor extends HttpServlet {
	public void doGet(HttpServletRequest request, 
			HttpServletResponse response) throws IOException{
		
		response.setContentType("text/html");
		PrintWriter out = response.getWriter();
		Cookie c = ServletUtil.getCookie(request, "RepeatVisitor", "yes");
		
		String title="";
		if(c.getValue().equals("yes")){
			title = "welcome aboard";
			c.setValue("no");
			response.addCookie(c);
		}else{
			title = "welcome back";
		}
		
		out.println("<h1>" + title + "</h1>");
 
	}
}