The pre-Logon page is automatically displayed after logon.

Today, we want to implement this function. On the internet, Referer is used for implementation. However, Referer also has several problems:
1. When you open a new window and enter the URL directly, the browser does not seem to send a referer header.
2. It is not generated when it is opened through functions such as JS window. Open.
3 Referer sending or not is configurable in the browser (of course, it is estimated that not many people will set it)

Here I will use struts2 to describe my implementation method:

Package com. snil. commons. interceptors;

Import java. util. enumeration;
Import java. util. List;
Import java. util. Map;

Import javax. annotation. resource;
Import javax. servlet. http. Cookie;
Import javax. servlet. http. httpservletrequest;
Import javax. servlet. http. httpservletresponse;
Import javax. servlet. http. httpsession;

Import org. aopalliance. Intercept. Invocation;
Import org. Apache. commons. Lang. stringutils;
Import org. Apache. log4j. Logger;
Import org. Apache. struts2.servletactioncontext;
Import org. Apache. struts2.strutsstatics;
Import org. hibernate. criterion. expression;
Import org. springframework. Context. annotation. scope;
Import org. springframework. stereotype. Controller;

Import com. opensymphony. xwork2.actioncontext;
Import com. opensymphony. xwork2.actioninvocation;
Import com. opensymphony. xwork2.interceptor. abstractinterceptor;
Import com. Snail Il. commons. basedao. ibasedao;
Import com. snil. component. Beans. Huiyuan;
@ Scope ("prototype ")
@ Controller ("logininter ")
Public class logininter extends actinterceptor
{
Private Final Static logger = logger. getlogger (loginter. Class );
Public final static string session_key = "user ";
Public final static string cookie_key = "12cd ";
Public final static string goto_url_key = "going_to ";
@ Resource (name = "basedao ")
Protected ibasedao basedao;
@ Override
Public String intercept (actioninvocation Invocation) throws exception
{
Httpservletrequest request = servletactioncontext. getrequest ();

Httpservletresponse response = servletactioncontext. getresponse ();
Httpsession session = request. getsession ();
// Determine whether the user is logged on through the session. If no logon is found, the cookie is read.
If (session! = NULL & session. getattribute (session_key )! = NULL)
{
Return invocation. Invoke ();

}
Cookie [] cookies = request. getcookies ();
If (cookies! = NULL & cookies. length! = 0)
{
For (Cookie: cookies)
{
If (cookie_key.equals (cookie. getname ()))
{
String value = cookie. getvalue ();
If (stringutils. isnotblank (value ))
{
List <Huiyuan> Huiyuans = basedao. findentityproperty (Huiyuan. Class, expression. eq ("yonghuming", value ));
If (Huiyuans. Size () = 0)
{
Cookie. setpath ("/");
Cookie. setvalue (null );

Cookie. setmaxage (0 );
Response. addcookie (cookie );
Return "Index ";
}
If (Huiyuans. Get (0 )! = NULL)
{

Session. setattribute (session_key, Huiyuans. Get (0 ));
Logger.info ("read COOKIE: continue ");
Return invocation. Invoke ();
}

}
}
}
}
// The key point is to set the original request URL.
Settogoingurl (request, session, invocation );
Return "Index ";
}
Private void settogoingurl (httpservletrequest request, httpsession session, actioninvocation Invocation)
{
// Use Referer directly if it is not empty. If it is null, we will obtain the namespace, action name, and request parameters respectively.
// Create a new URL and save it in the session
String url = request. getheader ("Referer ");
Logger.info ("URL to be switched:" + request. getheader ("Referer "));
If (url = NULL | URL. Equals (""))
{
Url = "";
String Path = request. getcontextpath ();
String actionname = invocation. getproxy (). getactionname ();
String namespace = invocation. getproxy (). getnamespace ();
If (stringutils. isnotempty (namespace ))
{
Url = URL + path + namespace;

}
If (stringutils. isnotempty (actionname ))
{
Url = URL + "/" + actionname + ". Action" + "? ";
}

Map <string, string []> zzmap = request. getparametermap ();
If (zzmap! = NULL)
{
For (string S: zzmap. keyset ())
{
String [] value = zzmap. Get (s );
For (string VAL: value)
{
Url = URL + S + "=" + Val + "&";
}

}
}
Logger.info ("complete URL:" + URL );
}

Session. setattribute (goto_url_key, URL );


}
Public void setbasedao (ibasedao basedao)
{
This. basedao = basedao;
}

}