Servlet课程0426（九）Servlet服务器端创建Cookie和客户端读取Cookie

服务器端创建Cookie：

Win7默认Cookie位置

C:UsersAdministratorAppDataRoamingMicrosoftWindowsCookies

CookieTest1.java

//CookieTest1
package com.tsinghua;

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

public class CookieTest1 extends HttpServlet{
	public void doGet(HttpServletRequest req, HttpServletResponse res)
	{

		try{

		//解决中文乱码
		res.setCharacterEncoding("gbk");
		PrintWriter pw = res.getWriter();
		pw.println("<html>");
		//当用户访问该Servlet时，就将信息创建到该用户的cookie中

		//1.现在服务器端创建一个cookie
		Cookie myCookie = new Cookie("color1","red");

		//2.该cookie的存在时间
		myCookie.setMaxAge(30);
		//如果你不设置存在时间，那么该cookie将不会保存

		//3.将该cookie写回到客户端
		res.addCookie(myCookie);

		pw.println("已经创建了cookie");


		}
		catch(Exception ex)
		{
			ex.printStackTrace();
		}

	}

	 //处理get请求
	 //req用于获得客户端(浏览器)的信息
	 //res用于向 客户端(浏览器)返回信息
	public void doPost(HttpServletRequest req, HttpServletResponse res)
	{

		this.doGet(req,res);

	}


}

客户端读取Cookie

//如何读取Cookie案例
package com.tsinghua;

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

public class CookieTest2 extends HttpServlet{
    public void doGet(HttpServletRequest req, HttpServletResponse res)
    {

        try{

        //解决中文乱码
        res.setCharacterEncoding("gbk");
        PrintWriter pw = res.getWriter();

        //客户端得到所有cookie信息
        Cookie[] allCookies = req.getCookies();
        int i = 0;
        //如果allCookie不为空
        if(allCookies != null)
        {
            //从中取出cookie
            for (i = 0; i<allCookies.length; i++)
            {
                //依次取出
                Cookie temp = allCookies[i];

                if(temp.getName().equals("color1"))
                {
                    //得到cookie的值
                    String val = temp.getValue();
                    pw.println("color1="+val);
                    break;
                }
            }
            if(allCookies.length == i)
            {
                pw.println("cookie过期");
            }
        }else
            {
                pw.println("不存在color1这个cookie/或者是过期");
            }


        }
        catch(Exception ex)
        {
            ex.printStackTrace();
        }

    }

     //处理get请求
     //req用于获得客户端(浏览器)的信息
     //res用于向 客户端(浏览器)返回信息
    public void doPost(HttpServletRequest req, HttpServletResponse res)
    {

        this.doGet(req,res);

    }


}