Session Management

Wed, 14 May 2008 02:21:13 MDT

I,m reading Head first Servlets & JSP Chapter 6 Session Management.

For sending a Kookie in response or getting a Kookie in request we create a HttpSession Object as below

HttpSession session1 =request.getSession() ....(1)
or,
HttpSession session1 =request.getSession(false)...(2)

With the above session object created,the container takes care of generating sessionID,
creating a new Kookie object,stuffing the sessionID into Kookie and stuffing the Kookie
as a part of response.On subsequent requests,the container gets the sessionID,from the Kookie in the request,
matches the sessionID with the existing session and associates the session with current request.

Dont want the control to return to the servlet and execute after the forward

Wed, 14 May 2008 01:07:13 MDT

I use requestDispatcher.forward under an if condition in my servlet. After this line there are some code. I dont want the control to come back and execute the code. Is there are any option we can set in the request or response so it doesnt come back to the servlet.

eg:

if(LOBList == null || LOBList.isEmpty())
{
req.setAttribute(LaserConsts.LOBEXCEPTION,"loberror");
getRequestDispatcher(LaserConsts.ERROR_PAGE).forward(req, res);
return;
}

remaining code

how to submit a request to a url

Tue, 13 May 2008 06:33:11 MDT

Hi Ranchers,

I am trying to submit my page to a url formed in a javascript can you please guide me how to do it.

the problem i am facing is the page gets submitted to the action mentioned in form tag.

if i remove it than it doesn't go anywhere.

On DB Connections, MVC2, and Sessions

Tue, 13 May 2008 05:27:11 MDT

Hi all,

I have some questions for you. I cannot specifically point out what kind of problem I am encountering in my application, but here's what's happening:

- I have a web application project deployed in the Sun Glassfish Sever, the project follows the MVC2 architecture.
- I am using connection pool for database connection.
- I have an OracleDAOFactory with one method getConnection() which gets a DataSource object from the connection pool.
- I have a SuperDAO which creates a Connection object by calling the getConnection() method in the OracleDAOFactory. This call to getConnection() is in its constructor.
- Within SuperDAO I have methods like performQuery(String query), performUpdate(String query...

Starting Servlets...

Mon, 12 May 2008 15:49:08 MDT

Hello all...

I am preparing to dive in the pool of Servlets and JSPs. What (software/application) is it that I need to have on my personal computer to start coding and testing servlets..?

Regards,

Rekha Anand

problem in accessing a distributed EJB through a servlet

Mon, 12 May 2008 09:19:08 MDT

Dear all,
I'm a trying to call a stateless session bean which has its home and component interfaces, which prints the name it receives from the servlet client.
I'm trying to access a remote server EJB beans, which has been registered with JNDI & when deploying the EJB beans onto the Jboss server which operates in localhost: 8081 it has shown

code:

 
 
20:19:16,890 INFO [EjbModule] Deploying greetBean
 20:19:17,109 INFO [ProxyFactory] Bound EJB Home 'greetBean' to jndi 'greetJndi'
20:19:17,125 INFO [EJBDeployer] Deployed: file:/C:/jboss-4.0.5.GA/server/default/deploy/greet.jar

This is my servlet which is there in tomcat contai...

How Remove Servlets From Server Memory

Mon, 12 May 2008 00:33:06 MDT

Hi,

I like to know how we can unload the Servlets from the server memory when they are not needed. For Example we have 1000 Servlets running in a Prod machine. Most of them are not used, how we can remove the Servlets from the Server memory...

Is there any options provided by the Server like websphere or Tomcat....

Listeners not to be configured in DD

Sat, 10 May 2008 02:35:01 MDT

In Head First Servlets and JSP 1.4 on P-254,its mentioned that you don't need to configure session Binding listeners in DD but got to configure all other listeners except this in DD

I was going through whiz labs Mock questions and they have HttpSessionActivation Listener also in list besides HttpSessionBindingListeners?????

I think Head First version is right but still want to confirm.Please let me know

-Salil

jsp and servlet in same screen

Fri, 9 May 2008 22:43:00 MDT

Hi,
can i have jsp and servlet in a single page?I am having a screen in jsp which displays the details of the caller to the agent.I need to display in the same page about another caller if anyone is in queue by fetching the customer waiting database.How can i do this?any idea about this ?I thought to do it in html frames.one frame which displays the details screen which is in jsp and the other frame should display that a caller is waiting in queue by using servlet which checks the database for every five seconds whether anyone is in queue and displays the message to the agent.Is this method correct.If not how
can i do this?

Thanks

HttpRequest.setParameter()

Fri, 9 May 2008 21:45:00 MDT

hi
i wanted to add the parameter value to the HttpServlet request from my Serlet Filter.

I have to clue that i can achive this by HttpServletRequestWrapper . can any one help me to explain me ...

Call destroy() inside init()

Fri, 9 May 2008 09:34:58 MDT

What will happen if we call destroy() method from inside the init() method?

Update Servlet version from 2.4 to 2.5

Fri, 9 May 2008 07:32:58 MDT

I tried to change the servlet version of my web application from 2.4 to 2.5.

The web application in 2.4 which was developed and runned successfully in a Jetty server did not work properly with 2.5. The problem lied with JSTL. It would not recognize the ${} method of accessing variables.

All I did changes was the descriptor in the web.xml from
<web-app id="WebApp_ID" version="2.4" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/j2ee"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd"> (http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd)

to the following:
<web-app id="WebApp_ID" version="2.5...

Can anyone tell me about webserver?

Fri, 9 May 2008 05:04:58 MDT

Hi All,
Please any one say about web servers ,why we can use this,and where we can use this,and can we get free webserver for hosting the jar and jad files
if it is can you tell me how.

Please any body help in this,

Thanks in Advance,
Geeta

[ Edited to fix shouting in subject - Paul Sturrock ]

how to run simply servlet program

Fri, 9 May 2008 01:00:57 MDT

i am new to this topic. i have written servlet program but it is error like some jar file is required...so pls help me

servlet

Fri, 9 May 2008 00:16:57 MDT

If my browser does not support Cookie,and my server sends a cookie instance What will happen ?

java

Fri, 9 May 2008 00:12:57 MDT

Suppose If we have variable ' I ' in run method, If I can create one or more thread each thread will occupy a separate copy or same variable will be shared ?

servlet

Fri, 9 May 2008 00:10:57 MDT

In servlets, we are having a web page that is invoking servlets username and password ? which is cheks in the database ? Suppose the second page also If we want to verify the same information whether it will connect to the database or it will be used previous information?

log method of servlet context

Thu, 8 May 2008 22:54:57 MDT

log
public void log(java.lang.String msg)
log
public void log(java.lang.Exception exception,
java.lang.String msg)
log
public void log(java.lang.String message,
java.lang.Throwable throwable)

With the above log methods of the ServletContext,where the log file gets created.Where can we view those logs?

Two servlets with same URL???

Thu, 8 May 2008 09:26:55 MDT

Hi all,

I wanted to know if this crazy idea would work.

I have a servlet which acts as an entry point to my web service which is coded in Java completely. Now, I want to change the same web service to AXIS. I don't want to change the URL for it on my web server. And I want to deploy both of them at the same time, and route requests to the corresponding service depending on the requests.

I hope now you believe I'm crazy.

I want to know if there is a way I can implement this.

Thanks,
Anish

Reading csv file from within servlet problem

Thu, 8 May 2008 04:58:55 MDT

Hello,

I have a web app (Servlet/JSP) and I intend using FlatPack to parse a csv file but I am having trouble simply reading the file in.

Directory Structure

Web Pages
|_META-INF
|_WEB-INF
|_data_feeds
|_Demo.csv

The code I am using is below and it throws the following exception:

quote:

SEVERE: Servlet.service() for servlet FeedParser threw exception
java.net.MalformedURLException: no protocol: /mobileseeker/data_feeds/Demo.csv
at java.net.URL.<init>(URL.java:567)
at java.net.URL.<init>(URL.java:464)
at java.net.URL.<init>(URL.java:413)
at org.digitalturtle.sandpit.FeedPa...

cookies problem

Thu, 8 May 2008 04:58:55 MDT

Hi,
I need to display a popup screen which gets all the details of the caller from a servlet.This page displays well.But when i click the dispose button in this popup page ,it should go to an refresh screen.But when i dispose,The details which i got in popup screen are saved in the browser and i am unable to proceed further for another popup screen for next caller's details.my code follows:

code:

 
 
 public class Crmpopup extends javax.servlet.http.HttpServlet 
 implements javax.servlet.Servlet {
 Statement st;
 ResultSet rs=null;
 ResultSet rs1=null;
 Connection conn = null;
 
public Crmpopup() {
super();
} 

protected void doGet(HttpSe...

Security-related element in web.xml

Thu, 8 May 2008 04:08:55 MDT

Hi

Just want to check with all of you on the security features provided in web.xml.

How many of you actually use the element such as security-constraint, auth-constratint in web.xml file to enable security in your application?

I have been working for 2 years but all the access control is done programatically.

If any of you have done so, please share your experience or scenario where you use these elements.
I really appreciate it.

Thanks
Terence

PS:
I'm not sure if this is the right forum to ask.
If the moderator want to move the more relevant forum, please do so.

Servlet mapping

Thu, 8 May 2008 03:04:55 MDT

Hello There

How to do mapping between HTML and servlet.

How to create a WAR file

Wed, 7 May 2008 20:50:54 MDT

I have my servlet file Ch1Servlet.java and compiled it and also create DD web.xml and created the directory stucture WEB-INF inside it i place web.xml and classes folder and inside classes folder i place Ch1Servlet.class. I want to create WAR file to deploy in glassfish server.I am new to servlet .Thanks in advance .

File reading from any path

Wed, 7 May 2008 01:46:51 MDT

Hi all,

Can somebody tell me how can I read files from another directory/drive other than my application.

i.e my path of application in server = C:\deploy

I want to access the files from path = D:\Program Files\Java\rt.txt

Thanks in advance,

Kousik

html in variable inside a servlet

Tue, 6 May 2008 19:46:51 MDT

For my Servlet controller I forward to specific JSP depending on user action. I forward messages using sessions depending on the action and some of the messages need to have HTML <br> so I can break up the message line by line:

code:


if(something..)
{
 myMsg = "Hello world<br>";
 //forward this message to JSP ...
}
....

For good MVC skills, is it okay to forward html in a Servlet like above example?

what code will be there in init() of GenericServlet

Tue, 6 May 2008 10:20:49 MDT

hi,

1... what code will be there in init() and destroy() (overridden method from Servlet interface) of GenericServlet . ?

scenario::::

if override the destroy() of the GenericServlet in our own servlet class
like .... class Myservlet extends HttpServlet
{
.... here override destroy method
}

2. In this case, Is that destroy() of Myservlet class will be called by container?
3. is there any case like init(servletconfig) calling init() in GenericServlet ?... i mean destroy of Myservlet an call destroy of Genericservlet ..with super.destroy()?

Thanks,
Vinay...

exception llegalStateException , any body know the reason

Tue, 6 May 2008 05:30:49 MDT

I am getting this Exception i dont know exact cause of this , my functionality is working properly but console is showing this...
any idea about this ,

java.lang.IllegalStateException: getOutputStream() has already been called for this response
at org.apache.catalina.connector.Response.getWriter(Response.java:606)
at org.apache.catalina.connector.ResponseFacade.getWriter(ResponseFacade.java:195)
at org.apache.jasper.runtime.JspWriterImpl.initOut(JspWriterImpl.java:124)

JSP/Servlet - clarification needed

Tue, 6 May 2008 04:52:49 MDT

Hello,

I am writing a java webapp using JSP/Servlets and am looking for a little help regarding implementing something in a best practice approach. Here are the steps in my program:

1) User logs in to index.jsp
2) User goes to display.jsp
3) display.jsp opens XML file and displays it.

I initially thought that from within "display.jsp" I could call a bean (jsp:useBean) and have it return Objects from the XML file. The issue with this is that my XML file is included within my web application, so I do not want to hardcode the location to the XML file (as this could change depending on where it is deployed). I would be able to get past this by passing the realpath to the Bean, like:
<% myBe...

Servlet class

Mon, 5 May 2008 23:28:48 MDT

I am new to servlets.I have some doubts due to which i am not able to proceed.

I have Tomcat 5 deployed on my system. I want to know:

1. When is Servlet class loaded?How?What actually happens?

HELP i'm a newbie

Mon, 5 May 2008 13:34:47 MDT

I just recently started working with JSP ,could anyone please tell me how to access the local filesystem of the server the servlet is running in and display a list of the files or folders in it.I want to create a web application that will allow me to do this, but I don't know where to start.please help!!!!!

Clarrifications on doPut, doDelete

Mon, 5 May 2008 07:24:46 MDT

Hi,

In HttpServlet class we have some method doPut, doDelete, doHead, doOptions and doTrace.

1. what is need to introduce these method?

2. give me a practical situation, in which we can use these methods..

thanks,
Thennam

Display a Chart from a Servlet to JSP

Mon, 5 May 2008 05:58:46 MDT

How or what do I do to this servlet code or to reqesting JSP to get my chart to display?

code:


 
protected void doGet(HttpServletRequest arg0, HttpServletResponse arg1) throws ServletException, IOException {
HttpSession session = arg0.getSession(true);

String jReturnString = "";

MakeAChart2 mac = new MakeAChart2();

session.setAttribute("chart1",mac.chart);

JFreeChart chart = (JFreeChart) session.getAttribute( "chart1" ); 
 // set the content type so the browser can see this as it is 
 arg1.setContentType( "application/pdf" ); 
 
 int width = 640; 
 int height = 480; 
 Rectangle pagesize = new Rectangle( wid...

calling one servlet from another servlet

Mon, 5 May 2008 01:44:45 MDT

Hi,
How do i call one servlet from another?In one servlet named RefServlet,I am getting the username and password and updating some fields in database if the username matches with the database.Then i need to call another servlet page (AutoServlet)which is refreshing automatically containing a logout button.

Thanks

How to remove JSESSIONID cookie on session invalidation

Mon, 5 May 2008 00:26:45 MDT

Hi,

I am calling session.invalidate() in my web application but this does not remove the JSESSIONID cookie. So one of our customers has raised this as a security threat. They fear a scenario where a different user can do a back and refresh on same browser and use previous user's session.

So let me know of a way of invalidating the existing JSESSIONID cookie once session.invalidate has been called.

Writing image into WAR ???

Sun, 4 May 2008 01:50:33 MDT

Hi Ranchers,

I am finding it difficult to create and write an image into WAR file and get it through a jsp or html page.

How can I write a image into WAR deployment folder?

My requirement is upon request for a page, I have to get data and create a chart which I have to save it as png to display it along with some table.

Please help me in this regard.

Arabic language support in JAVA

Sat, 3 May 2008 02:44:30 MDT

Hi
I have developed the Email portlet and datas are returned from webservices. In my .java file, I have the variable messageo[1] which returns the email title and title may be in English or Arabic.

When variable has English message then it works fine for me but when variable has Arabic message it displays title like "???????".

If I test the Webservices(.wsdl file) then it's displays Arabic message, I think problem with my .java file because it's not reading Arabic message in .java file.

I tested the code like below but it's not working in both case.
In java:
String value = new String(messageo[1].getBytes("ISO-8859-1"), "UTF-8");
and
String value = new String(messageo[1].getByte...

Session

Fri, 2 May 2008 06:06:28 MDT

Hi,

Please clarrify my doubts..

1. when can we use URL writting, hidden fields, cookies and HttpSession to handle session?

2. if the client disabled the cookies, what will happen to the session? how can we handle the session if the client disabled the cookies?

3. is HttpSession uses Cookies ?

thanks ,
Thennam Pandian.

Need Coding

Fri, 2 May 2008 04:32:27 MDT

Hi,

I need the coding for how two clients in online chatting will communicate.
When i send some text message to another then that client has to reply to the first client.
please Help me.

Thanks in Advance

How to Clear unused Session Attributes

Thu, 1 May 2008 00:48:24 MDT

hi,

i'm working on j2ee web application,
regarding unsed sessions we are getting lots of problem,
how to handle such kind problems in future.
suggestions & guidance are welcome.

Thanking you
Karthikeyan R

servlet Map help

Wed, 30 Apr 2008 17:52:23 MDT

It's been a while since I have written any code and I am having an issue getting back into it.

I am currently working on creating servlet to pass info from all my forms to my business logic. However, I am having an issue with getting the data. This may be a topic for a different forum, but I figured I would ask here.

I tested out the servlet with the getParameter() method, and I can get the values. However, when I try to use the java.util.Map, I get blank values.

I think the issue may be that I forgot how to use the Map object. Here is my code:

out.println("<html>");
out.println("<head>");
out.println("<title>Servlet CalCartController&l...

Specifting zip file name in servlet

Wed, 30 Apr 2008 13:04:22 MDT

I am breezing along zipping up files in my servlet when I find that I cannot specify the name of the zip file!

ServletOutputStream out = response.getOutputStream();
ZipOutputStream zipOut = new ZipOutputStream(out);

response.addHeader("Content-Disposition", "attachment; filename=charts.zip");

The name of the zip file turns out to be the name of the servlet. I don't find any answer in the docs. How can I specify the file name?

Thanks,

Eric

why index.html

Wed, 30 Apr 2008 12:52:22 MDT

hello
I am using tomcat for my application in jsp/servlet.
i have one file named Enter.jsp. after starting the server and programme it will automatically call index.html. but suppose while starting I want to make call direct to my file i.e Enter.jsp. so how to call it directly without typing name in browser.
Is their any way to call user generated files directly without calling index.html

sendign PDF to screen while downloading

Wed, 30 Apr 2008 11:42:22 MDT

Hello:

I have a servlet which writes a PDF to the ServletOutputStream so that it gets sent to the browser or plugin.

Now I need the servlet to download 12 png files (that exist in memory) in addition to sending the aforementioned PDF to the browser.

IS this possible in one servlet?

Thanks

Eric

servlet-mapping

Wed, 30 Apr 2008 04:54:21 MDT

hi guys
is <servlet-mapping> mandatory for all <servlet> tags in web.xml
i have also read that every <servlet> tag should have <servlet-mapping>
but i found only <servlet> tag for quartz configuration like below

code:

 <servlet>
 <servlet-name>QuartzInitializer</servlet-name>
 <display-name>Quartz Initializer Servlet</display-name>
 <servlet-class>org.quartz.ee.servlet.QuartzInitializerServlet</servlet-class>
 <init-param>
 <param-name>config-file</param-name>
 <param-value>quartz.properties</param-value>
 </init-param>
 <i...

FTP using servlets.

Wed, 30 Apr 2008 04:14:21 MDT

Hello,

Please inform, how I can implement FTP using servlets.

Thanks
Neeraj.

what is difference between MVC1 & MVC2 pattern?

Wed, 30 Apr 2008 02:56:21 MDT

Hi,

please tell me the diff. between mvc1 & mvc2 pattern?

Autorefreshing a servlet page

Wed, 30 Apr 2008 00:12:20 MDT

Hi,
I want to auto refresh a servlet page for every 10 sec.I have checked it with a simple helloworld servlet program.But i dont find the page is getting refreshed automatically.I have used

code:

 
protected void doGet(HttpServletRequest request, HttpServletResponse response) 
 throws ServletException, IOException {
response.getWriter().write("Helloworld");
response.setHeader("Refresh","10");
}

Is this the correct code to refresh.anyone help me please.

Thanks in advance

http call questions

Tue, 29 Apr 2008 06:56:18 MDT

When we send a http request to server. Not talking about XHR requests
For example
( http://MyApp/getPageStream.jsp (http://MyApp/getPageStream.jsp) ) or any other http call.
Can we:-
1) Abort the request(for example say if user clicks cancel abort file upload request)
2)Delay request for say 2 sec.(e.g if user clicks twice in 2 sec sen call only once.)

Thanks

error in deploying servlets in tomcat

Tue, 29 Apr 2008 02:38:18 MDT

Hi
I am getting the following error ..
please send me the solution for this error.
-----
Tomcat Web Application Manager

Message: FAIL - Application at context path /myapp could not be started
------------
Thanks

JavaRanch Servlets

Session Management

Dont want the control to return to the servlet and execute after the forward

how to submit a request to a url

On DB Connections, MVC2, and Sessions

Starting Servlets...

problem in accessing a distributed EJB through a servlet

How Remove Servlets From Server Memory

Listeners not to be configured in DD

jsp and servlet in same screen

HttpRequest.setParameter()

Call destroy() inside init()

Update Servlet version from 2.4 to 2.5

Can anyone tell me about webserver?

how to run simply servlet program

servlet

java

servlet

log method of servlet context

Two servlets with same URL???

Reading csv file from within servlet problem

cookies problem

Security-related element in web.xml

Servlet mapping

How to create a WAR file

File reading from any path

html in variable inside a servlet

what code will be there in init() of GenericServlet

exception llegalStateException , any body know the reason

JSP/Servlet - clarification needed

Servlet class

HELP i'm a newbie

Clarrifications on doPut, doDelete

Display a Chart from a Servlet to JSP

calling one servlet from another servlet

How to remove JSESSIONID cookie on session invalidation

Writing image into WAR ???

Arabic language support in JAVA

Session

Need Coding

How to Clear unused Session Attributes

servlet Map help

Specifting zip file name in servlet

why index.html

sendign PDF to screen while downloading

servlet-mapping

FTP using servlets.

what is difference between MVC1 & MVC2 pattern?

Autorefreshing a servlet page

http call questions

error in deploying servlets in tomcat