import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.jsp.PageContext;

/**
*
* cookie操作类
*<br>功能：对cookie进行增查改删
*/
public class CookieUitl
{
/**
* 往客户端写入Cookie。
* <pre>
* 说明:
* maxAge:(单位秒)
* 0:删除Cookie
* -1:页面关闭时删除cookie
* </pre>
* @param name String
* @param value String
* @param maxAge int
* @param context PageContext
*/
public static void addCookie(String name,String value,int maxAge,PageContext context)
{
HttpServletResponse response=(HttpServletResponse)context.getResponse();
HttpServletRequest req=(HttpServletRequest)context.getRequest();
addCookie( name, value,maxAge, req, response);
}

/**
* 写入会话cookie，在页面关闭的时候这个cookie自动删除。
* @param name cookie名称
* @param value cookie值。
* @param context
*/
public static void addCookie(String name,String value,PageContext context)
{
HttpServletResponse response=(HttpServletResponse)context.getResponse();
HttpServletRequest req=(HttpServletRequest)context.getRequest();
addCookie( name, value,-1, req, response);
}

/**
* 添加cookie，cookie的生命周期为关闭浏览器即消失
* @param name
* @param value
* @param req
* @param response
*/
public static void addCookie(String name,String value,HttpServletRequest req,HttpServletResponse response)
{
addCookie( name, value,-1, req, response);
}

/**
* 添加cookie
* @param name cookie名称
* @param value cookie值
* @param maxAge cookie存活时间
* @param req
* @param response
*/
public static void addCookie(String name,String value,int maxAge,HttpServletRequest req,HttpServletResponse response)
{
if(response==null)return;
Cookie cookie=new Cookie(name,value);
cookie.setPath(req.getContextPath());
cookie.setMaxAge(maxAge);
response.addCookie(cookie);
}

/**
* 删除cookie
* @param name
* @param context
*/
public static void delCookie(String name,PageContext context)
{
HttpServletResponse response=(HttpServletResponse)context.getResponse();
HttpServletRequest request=(HttpServletRequest)context.getRequest();
delCookie(name,request, response);
}
/**
* 删除cookie
* @param name
* @param response
*/
public static void delCookie(String name,HttpServletRequest request, HttpServletResponse response)
{
addCookie(name, "", 0, request,response);
}

/**
* 根据Cookie名取得Cookie的值.
* 如果cookie 为空 则返回 null;
* @param name String
* @param context PageContext
* @return String
*/
public static String getValueByName(String name,PageContext context)
{
HttpServletRequest request=(HttpServletRequest)context.getRequest();
String str= getValueByName(name,request);
return str;
}

/**
* 根据cookie名称取得值
* @param name
* @param request
* @return
*/
public static String getValueByName(String name,HttpServletRequest request)
{
if(request==null)return "";
Cookie cookies[]=request.getCookies();
Cookie sCookie=null;
String svalue=null;
String sname=null;

if(cookies==null)
return null;
for(int i=0;i< cookies.length;i++)
{
sCookie=cookies[i];
sname=sCookie.getName();
if(sname.equals(name))
{
svalue=sCookie.getValue();
break;
}
}
return svalue;
}

/**
* 根据Cookie名判断Cookie是否存在.
* @param name String
* @param context PageContext
* @return String
*/
public static boolean isExistByName(String name,PageContext context)
{
HttpServletRequest request=(HttpServletRequest)context.getRequest();
return isExistByName(name,request);
}

/**
*
* @param name
* @param request
* @return
*/
public static boolean isExistByName(String name,HttpServletRequest request)
{

Cookie cookies[]=request.getCookies();
Cookie sCookie=null;

String sname=null;
boolean isExist=false;
if(cookies==null)
return false;
for(int i=0;i< cookies.length;i++)
{
sCookie=cookies[i];
sname=sCookie.getName();
if(sname.equals(name))
{
isExist=true;
break;
}
}
return isExist;
}

}