How to server-push to a JSP?

I want to refresh the content of a JSP as and when a collection available in server session is updated. The JSP displays the messages from this collection. Presently, I am using a meta tag, which refreshes the page after a specified time. But, this is not I want. I want it to somehow tell the JSP to refresh itself. I am open to ideas of putting an applet, socket programming, etc. But, I am not sure of how to go about it, as I am using Struts.
I hope, you must have got my problem. Can anybody help me?
Regards,
VK
[email protected]

HTTP is stateless - so no push technology. Refreshing is one workaround, Scripting/Applet is another. there is no way for the server (no matter if a servlet or any other server component) to tell the client something without being asked. HTTP is a simple request/response protocol. all "push" technologies for HTML pages use such workarounds that the client polls the server (refreshing, etc.) in short amount of times. if the server want's to "push" something, it really just answers a (poll) request from the client.
HTML is far to outdated. JSP, Struts, JavaServerFaces, etc. can't help that. It's time for a new internet protocol.

Similar Messages

Implementing Server Push

How can i implement a server push in my jsp pages?
any sample code would be appreciated.
The server pushes the data to the jsp when the
database changes because of an update.
Thanks

Http is a stateless protocol and cannot maintain a connection to the server. I am working on a project now that has the same type of requirement and we are using pushlet technology. You should have a look at the following
www.pushlets.com
Hope this helps
SD

Server Push in JSP

Hi AnyOne!
          I have a jsp, and a database . If a column in my table gets updated I
          want all of my clients who are connected to it , to see the refreshed value
          without click any refresh/Reload button on the browser. A kind of
          Server-Push.
          That is, If one client makes changes, then all of the other clients on the
          web should get intimated.
          How can I achieve this ?
          thanks
          vikas


Vikas,
          There was a article about the same in java world a while back.
          http://www.javaworld.com/javaworld/jw-03-2000/jw-03-pushlet.html
          But I believe this is bad design. I don't think using opened HTTP Connections
          to do a real time operation is not a good Idea. What if you are serving couple
          of hundred clients?
          Kumar.
          Vikas Jolly wrote:
          > Hi AnyOne!
          >
          > I have a jsp, and a database . If a column in my table gets updated I
          > want all of my clients who are connected to it , to see the refreshed value
          > without click any refresh/Reload button on the browser. A kind of
          > Server-Push.
          > That is, If one client makes changes, then all of the other clients on the
          > web should get intimated.
          >
          > How can I achieve this ?
          >
          > thanks
          > vikas

How can i connect to a SQL Server 2000 database usgin JSP?

I need (URGENT) to connect to SQL Server 2000 databse using JSP. I do not know how to program using JSP, so if anyone has any code snippet please let me see it. What i need is to give my site some login/password security.
Anyone?
Thx.

just create an ODBC of your database from control pannel -> administrative tools -> data sources (ODBC) ,double click it .....
go to the tab SYstem DSN , click on ADD button. select the driver for your connection. it will be the last one in the list "SQL Server".
click Next then give ur DSN name there, description and Server Name , on next give your username and password of SQL server. when it will be connected to the server celect your database from there and hence there will be an ODBC bridge same as in case of MS Access.
code for connecting to ODBC is
// DSN-NAME same as in System DSN.
// username and password are of your databse
try
          url = "jdbc:odbc:DSN-NAME";
          Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
          connect = DriverManager.getConnection( url,"username","password" );
          catch ( ClassNotFoundException cnfex ) {
                    setErrorMsg( cnfex.getMessage() );
          catch ( SQLException sqlex ) {
                    setErrorMsg( sqlex.getMessage() );
          catch ( Exception ex ) {
                    setErrorMsg( ex.getMessage() );
Now you are connected to the SQL Server ..... use connect object for further processing .........

Server Push redirecting to a pre-existing JSP

Question:
Has anyone tried to create a Server Push servlet that can be used to serve up pre-existing JSPs?
Is it even possible for a servlet to serve a pre-existing JSP or does the web page code have to be embedded within the servlet?

Hi, do you mean you want to redirect to another JSP?
you could use the "sendRedirect" method in the HttpServletResponse object.
for example:
public MyServlet perform(...HttpServletRequest request, HttpServletResponse response)
throws IOException, ServletException {
String redirectTo = "http://www.companyname.com/index.jsp";
response.sendRedirect(redirectTo);
}something like that....

How to use server push technology

I need to write a Chatroom by using Server-push technology. Who would like to offer some information about this technology for me? Thanks!!

Define "server-push" technology.client-pull is where the client pulls, via a specific request, information from the server.
Server-push is where the server pushes information to a client when that information becomes available. The client does not initiate the exchange.

Server Push in Servlets

Hi AnyOne!
          I have a servlet, and a database . If a column in my table gets updated I
          want all of my clients who are connected to it , to see the refreshed value
          without click any refresh/Reload button on the browser. A kind of
          Server-Push.
          That is, If one client makes changes, then all of the other clients on the
          web should get intimated.
          How can I achieve this ?
          thanks
          vikas


I read the OP's message and imediately thought oh, cool, MVC candidate :-)          If I wanna talk about MVC I would prefer Sun's Design Patterns group.
          Kumar.
          [email protected] wrote:
          > "Mettu Kumar" <[email protected]> wrote in message
          > news:[email protected]...
          > > Ryan,
          > >
          > > I was not commenting on MVC pattern. I am talking about the problems
          > > pushlets implementation could potentially cause.
          >
          > Mettu, we completly crossed paths my friend. I read the OP's message and
          > imediately thought oh, cool, MVC candidate :-) Silly me! I understand what
          > you are talking about now :-)
          >
          > > 1. If you are serving 10,000 clients, probably a given instance your
          > server will
          > > be serving 100 or 1000 of the them. but with pushlets you have 10, 000
          > > conenctions open siumultaneously and your server is serving all the client
          > 100%
          > > of the time.
          >
          > No, you're right that isn't good.
          >
          > > Do you think this would scale? Imagine the number of threads on server.
          > > 2. This could potentially bring down the web server you are using.
          > >
          >
          > It would scale right up to the time the server came crashing down :-) Yes,
          > if the server kept a single connection, thread of execution, open to every
          > client while the client was running that would be not so hot indeed,
          > especially if your clients increased exponentially. This is precisely why I
          > like the callback method on each client, kind of a pain to implement though.
          >
          > >
          > > Kumar.
          > >
          > > [email protected] wrote:
          > >
          > > > I wasn't referring to the article on pushlets you mentioned when I said
          > the
          > > > idea of MVC was a valid one, nor have I read the article as I respond
          > but
          > > > heres the idea I was describing which is based on the concept of MVC.
          > It
          > > > provides perfectly for the scenario the OP described IMO. I think, at
          > least
          > > > based on what I've seen, that the notion of MVC in the J2EE sector is
          > used
          > > > mostly as a means to seperate business logic from presentation logic.
          > It
          > > > doesn't allow for any mechanisms to notify the ``views" when data
          > ``model"
          > > > changes. This is no big deal I guess for most applications but it does
          > > > break the MVC paradigm IMO. To aleiviate this problem we incorporate an
          > > > observer pattern to notify each subscribing view when the model changes.
          > > > There really isn't any difference in my mind between push and pull where
          > > > pull is a standard RFC 2616 request and push is a simple callback to the
          > > > object registered with the controller (servlet, jsp). If the server can
          > > > handle a thousand or so concurrent requests why couldn't it handle a
          > > > thousand concurrent callbacks. You could probably improve this by
          > > > multi-threading the controller. Just some thoughts I would like to hear
          > > > yours :-)
          > > >
          > > > ~Ryan
          > > >
          > > > "Mettu Kumar" <[email protected]> wrote in message
          > > > news:[email protected]...
          > > > > Ryan,
          > > > >
          > > > > Did you ever try to use to Pushlets serving thousands of clients?
          > > > > Why did you think its a good design? If you feel its a good design,
          > let
          > > > us
          > > > > know whats good about it.
          > > > >
          > > > > Kumar.
          > > > >
          > > > > [email protected] wrote:
          > > > >
          > > > > > "Mettu Kumar" <[email protected]> wrote in message
          > > > > > news:[email protected]...
          > > > > > > Vikas,
          > > > > > >
          > > > > > > There was a article about the same in java world a while back.
          > > > > > > http://www.javaworld.com/javaworld/jw-03-2000/jw-03-pushlet.html
          > > > > > >
          > > > > > > But I believe this is bad design. I don't think using opened HTTP
          > > > > > Connections
          > > > > > > to do a real time operation is not a good Idea. What if you are
          > > > serving
          > > > > > couple
          > > > > > > of hundred clients?
          > > > > > >
          > > > > > > Kumar.
          > > > > > >
          > > > > >
          > > > > > It's a perfectly valid design. OP, check out MVC and the observer
          > > > design
          > > > > > pattern I think you'll find what you're looking for there.
          > > > > >
          > > > > > ~Ryan
          > > > > >
          > > > > > > Vikas Jolly wrote:
          > > > > > >
          > > > > > > > Hi AnyOne!
          > > > > > > >
          > > > > > > > I have a servlet, and a database . If a column in my table gets
          > > > updated
          > > > > > I
          > > > > > > > want all of my clients who are connected to it , to see the
          > > > refreshed
          > > > > > value
          > > > > > > > without click any refresh/Reload button on the browser. A kind
          > of
          > > > > > > > Server-Push.
          > > > > > > > That is, If one client makes changes, then all of the other
          > clients
          > > > on
          > > > > > the
          > > > > > > > web should get intimated.
          > > > > > > >
          > > > > > > > How can I achieve this ?
          > > > > > > >
          > > > > > > > thanks
          > > > > > > > vikas
          > > > > > >
          > > > >
          > > > >
          > >

How do you invoke a simple jsp

hi,
i have a very simple jsp that displays the current time. it works on my tomcat server (installed on my computer). i purchased a domain from yahoo, say, www.beginer.com and uploaded the jsp file to the yahoo server. but when i referenced it with the url www.beginer.com/MyJSP.jsp, a download dialog popped up.
so, how do you get the browser to display the dynamic contents of the jsp file?
thanks.

Did you ask Yahoo whether their server supports servlets and JSPs? Or did you just assume that? I would expect that it doesn't.

Urgent....How can i redirect to my jsp page from servlet in init() method..

How can i redirect to my jsp page from servlet in init() method..Becoz that servlet is calling while server startsup..so im writing some piece of code in init() method..after that i want to redirect to some jsp page ...is it possible?
using RequestDispatcher..its not possible..becoz
RequestDispatcher rd = sc.getRequestDispatcher("goto.jsp");
rd.foward(req,res);
Here the request and response are null objects..
So mi question can frame as how can i get request/response in servlet's init method()..

Hi guys
did any one get a solution for this issue. calling a jsp in the startup of the servlet, i mean in the startup servlet. I do have a same req like i need to call a JSP which does some data reterival and calculations and i am putting the results in the cache. so in the jsp there in no output of HTML. when i use the URLConnection i am getting a error as below.
java.net.SocketException: Unexpected end of file from server
at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:707)
at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:612)
at sun.net.www.http.HttpClient.parseHTTPHeader(HttpClient.java:705)
at sun.net.www.http.HttpClient.parseHTTP(HttpClient.java:612)
at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLCon
nection.java:519)
at com.toysrus.fns.alphablox.Startup.callJSP(Unknown Source)
at com.toysrus.fns.alphablox.Startup.init(Unknown Source)
at org.apache.tomcat.core.ServletWrapper.doInit(ServletWrapper.java:317)
so plz do let me know how to call a jsp in the start up of a servlet.
Thanks
Vidya

How to Hightlight the Data in Jsp Page

How to Hightlight the Data in Jsp Page,
I am doing doing search page,based on values given search page those are sent to servlet,in servlet based on some conditions if particuler id i am getting then i am redirecting to Respective jsp page with highlight the data from database..
Thanks in advance...

"Highlighting data in JSP sounds strange".
Without looking at your search specific algorithms I feel you are finally going to display a page (HTML content) to user which contains highlighted text. Highlighting is not directly related to server side language you use (JSP, ASP, PHP etc.). This is purely HTML and CSS. However, server side script (such as JSP) should generate HTML content for getting highlight effect.
Following HTML shows highlighted text using background-color property on span element.
<html>
<head>
    <title></title>
    <meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
</head>
<body>
      <p style="font-size:1.1em">This is a long paragraph which contains <span style="background-color: yellow;">highlighted text</span> and non highlighted text.</p>
</body>
</html>Thanks,
Mrityunjoy
Edited by: mrityunjoy on 14 Jun, 2010 3:30 AM

How to use SSL Technology in JSP.

Can anybody Tell me that How to use SSL Technology in JSP ?
I am using Apache Tomcat 5.0.28 Server.
How to configure the Tomcat server so that it will access any web application supported by Tomcat via SSL ?
Thank you very much in advance.

The JSP does not need to know that the request is coming over SSL. If the application must be over SSL, but the server also allows non-SSL communication, then, like I said, you need to build in a Filter that will check if the incoming request is an https or http request and redirect to the https url if the request was http. And you can do that using the method listed in the previous post. As far as setting up the SSL certificate for Tomcat to use, refer to the Tomcat Documentation that comes with the server. Other than those two things, you don't need to know anything else about SSL inorder to run an SSL application through a Tomcat server (or any other enterprise server either, for that matter), but do an internet search for SSL and maybe one or two other keywords that apply to your situation and you should find plenty that will help.

Hi, how to use URL encoding in jsp

hi, how to apply URL encoding in jsp for a string, could u pls suggest some ideas to use URL encoding in jsp
thank you in advance

hi, thnx for the reply, but my problem is to use url encoding method
i would u like to know how to represent in jsp program i have asp code some thing like this
href='/project/tel_number.asp?team=<%=DbRecTeam("id")%>&name=<%=Server.URLEncode(DbRec("name"))%>'
i would like to know how replace that Server.URLEncode stmt in jsp, could u pls suggest some equivalent method for the above stmt
thanx in advance

Please suggest how to handle User Transactions in JSP using JTA

we are using Websphere application server with DB2, Can anyone suggest how to maintain the transactions in JSP ?

What transactions?

Server-Push

I read somewhere that Flex Data Services provides Server-Push
functionality. That is, the server starts a conversation with the
client. It's obvious that, In order to such thing ocurr, there has
to be a persistent connection between server and client.
I've being reading about Data Management Service to learn how
to implement this Server-Push and all I see is about a method
called Fill() that is thriggered from the client and syncronizes
it's data with the server. But it's not server-push
Does it really exist?

Hi,
When you create a DataService and fill your collection. The
collection becomes managed. You don't have to call fill again if
there is any change in the data. Server pushs updates to clients
when the client's dataservice is using rtmp channel. It is a live
connection between the server and the client. For example,
you fill(collection, "hqsql", from products where price <
100). If one of the product's price increases, server push a
message to your collection to remove it. If a product's product's
price decrease, it will be added to the collection. The push is
happened based on your fill method.
William Chan

Use SAP Application server name in a jsp in ISA

Hello,
We need to use SAP application server name in a jsp file. Any suggestions on how to do this?
Thanks
Archana
Edited by: Archana Swaminathan on Jan 9, 2009 1:02 PM

Archana,
The web application server can be determined in the JSP by the isa tag.
<isa:webappsURL
But you can also get the actual value by using WebUtil class. This class has all features that isa tag provides. As such you can get the web application URL using
import com.sap.isa.core.util.WebUtil;
String webAppURL = WebUtil.getAppsURL(PageContext pageContext,
boolean Secure,
String name,
String params,
String anchor,
boolean completeURL);
But if you are asking for SAP application server that is different from what I have explained above, then I don't have a clue. If you are asking for MimeURL, where you have the images stored, you can use MimeURL class.
Easwar Ram
http://www.parxlns.com

How to server-push to a JSP?

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