cookietest.java

Java网络编程与分布式计算, 主要分析java网络各方面的编程, 提供许多实用安全

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;

// Chapter 10, Listing 4
public class CookieTest extends javax.servlet.http.HttpServlet
{
 public void doGet(HttpServletRequest req,
      HttpServletResponse res) throws IOException
    {
		OutputStream out  = res.getOutputStream();
		PrintWriter pw = new PrintWriter ( new BufferedWriter (
            new OutputStreamWriter ( out ) ) );

		Cookie[] cookies = req.getCookies();
		Cookie current = null;

		// Check to see if no cookies exist
		if(cookies != null)
		{
			// For each and every cookie, display name and value
			for(int i=0;i<cookies.length;i++)
			{
			 pw.println("name="+cookies[i].getName());
			 pw.println("value="+cookies[i].getValue());
			 pw.println("version="+cookies[i].getVersion());
			 if(cookies[i].getName().equals("cookie")) 
			 {
				 current=cookies[i];
			 }
			 pw.println();
			}

			
		}

		int count=0;
		if(current != null)
		{
		  count = Integer.parseInt(current.getValue());		  
		  
		  // Add new cookie, so we have more than one cookie stored in browser
		  res.addCookie(new Cookie("previouscookie",new Integer(count).toString()));

		  count++;
		}

		// Increment count
		pw.println("Count of value stored in cookie = "+count);
		count++;

		// Add cookie to save state data for next invocation
		res.addCookie(new Cookie("cookie",new Integer(count).toString()));

		pw.flush();	  
		pw.close();
    }
}