Re: Get the project path using Java. - Java Discussion Boards

Global Variable - Problem in diff. session.

Nanda_MR16-May-12 22:04

Nanda_MR

16-May-12 22:04

Hi to all,

Java

public class xyz {

public static int gUserID = 1;

}

When 1st user Login gUserID value is = 5
and second user login gUserID value is = 7

Problem is 1st user refresh or re-direct to another page gUserID is changing to 7.

How to set Global variable for session or any solution to above problem.

Thanks.

Re: Global Variable - Problem in diff. session.

Nagy Vilmos16-May-12 22:27

Nagy Vilmos

16-May-12 22:27

How is the variable being updated?

The single variable is used by every instance of the class. If you want each instance to have a userId then you need something like this:

Java

public class Test {
    // note it's private! This stop anything else from changing it.
    private static int nextUserId = 1;

    private int userId;
    public Test() {
        this.userId = Test.nextUserId++;
    }

    public int getUserId() {
        return this.userId;
    }
}

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Re: Global Variable - Problem in diff. session.

Nanda_MR16-May-12 22:40

Nanda_MR

16-May-12 22:40

Hi Nagy Vilmos,

I m update gUserID from database. As soon as login to application. I m setting corresponding user id to that variable and I m utilizing that variable in complete project as global variable.

here I m facing problem. As soon as 2nd person login The Value is reset (2nd user id is updating).

I m trying your method now Thanks.

Re: Global Variable - Problem in diff. session.

Nagy Vilmos16-May-12 23:26

Nagy Vilmos

16-May-12 23:26

Now I understand.

You have an instance for each user, so the variable must not be static. If it is possible to set the value in the constructor, then that is the best thing because you can make the member variable final and so it cannot be changed.

It is strongly advised to not expose member variables outside the class, it is ALWAYS better to use in this case a method; as I used in my example. If the variable is final, then you can to some extent relax the rule as there is no way it can be changed; but this is normally reserved for constants.

Re: Global Variable - Problem in diff. session.

TorstenH.17-May-12 1:17

TorstenH.

17-May-12 1:17

my +5.

I would like to point out that the UserID should also be an automatically created number that the user object should not modify - it's hard to identify the data otherwise.

regards Torsten
When I'm not working

Re: Global Variable - Problem in diff. session.

jschell17-May-12 11:18

jschell

17-May-12 11:18

Nanda_MR wrote:
How to set Global variable for session

You start by researching how to handle session data in a web application.

Get the project path using Java.

hansoctantan16-May-12 0:39

hansoctantan

16-May-12 0:39

Hi,

I have a problem on getting the project path of a web application.
Reason on getting the project path is I'm uploading a PDF Files to the project path so that I can open it to the browser, I'm hoping to do this http://localhost:8080/PDFviewer/UploadedFiles/sample.pdf.

I have found something in the Internet but the path is not in my project path

Java

getServletContext().getRealPath("/");

My project path is D:\Java\Java Web Projects\PDFviewer but the above code is giving me D:\Java\Java Web Projects\.metadata\.plugins\org.eclipse.wst.server.core\tmp0\wtpwebapps\PDFviewer

Can anybody please suggest a way of getting the application path in java.

Thanks... Thumbs Up | :thumbsup:

Re: Get the project path using Java.

TorstenH.16-May-12 0:59

TorstenH.

16-May-12 0:59

The path the system gives you is correct, because the web server is placed in the wtpwebapps folder.

Try to deploy it and see if the path comes up correct on a test system. I assume so.

regards Torsten
When I'm not working

Re: Get the project path using Java.

hansoctantan16-May-12 4:21

hansoctantan

16-May-12 4:21

Thank you very much it work perfectly what I expected... Laugh | :laugh:

Even if its not in my Eclipse Web Project it can view the pdf.

Thumbs Up | :thumbsup:

Re: Get the project path using Java.

TorstenH.17-May-12 1:18

TorstenH.

17-May-12 1:18

you're welcome.

This can be confusing, one is never secure to not struggle on such things.

regards Torsten
When I'm not working

Re: Get the project path using Java.

hansoctantan18-May-12 0:01

hansoctantan

18-May-12 0:01

yes, I'm really confused...
I can't see the uploaded files in my Eclipse App..

convert video to byte

jiojo15-May-12 23:30

jiojo

15-May-12 23:30

want to convert the content of video to byte in java could any body help me to do that?

Re: convert video to byte

TorstenH.16-May-12 0:56

TorstenH.

16-May-12 0:56

convert video to byte[^]

asking once should be enough.

regards Torsten
When I'm not working

Video Conferencing using Java Media Framewrok and Servlet.

Solanki Savan15-May-12 23:09

Solanki Savan

15-May-12 23:09

Please anybody help me to implement Video Conferencing in my project Virtual Classroom using Java Media Framework and servlet.

Thanks

Re: Video Conferencing using Java Media Framewrok and Servlet.

TorstenH.16-May-12 1:03

TorstenH.

16-May-12 1:03

Chance 1: big buget. Call me!

Chance 2: You might want to read this: Documentation on JMF[^]

regards Torsten
When I'm not working

Overloading Concepts

Ayyanar G11-May-12 3:27

Ayyanar G

11-May-12 3:27

What is exact diff. between the operator,constructor and method overloading.....Give some examples also.... Confused | :confused:

Re: Overloading Concepts

TorstenH.11-May-12 3:58

TorstenH.

11-May-12 3:58

Classes and Objects[^]

Overriding Methods[^]

I can recommend to by a good book explaining the basics. And I can recommend to read them even one has already worked in the business( kind of back to roots)

regards Torsten
When I'm not working

problem of a deployment in tomcat server

Bouali tayeb10-May-12 0:04

Bouali tayeb

10-May-12 0:04

when i want to deploy my application in tomcat server it can't and this is the error message

init:
deps-module-jar:
deps-ear-jar:
deps-jar:
library-inclusion-in-archive:
library-inclusion-in-manifest:
compile:
compile-jsps:
Undeploying ...
undeploy?path=/Mango
OK - Application non-déployée pour le chemin de contexte /Mango
In-place deployment at D:\PFE\Mango\build\web
deploy?config=file%3A%2FC%3A%2FUsers%2FBouali%2FAppData%2FLocal%2FTemp%2Fcontext4268238340729989227.xml&path=/Mango
FAIL - Deployed application at context path /Mango but context failed to start
D:\PFE\Mango\nbproject\build-impl.xml:847: The module has not been deployed.
See the server log for details.
BUILD FAILED (total time: 2 seconds)
I await your answers in short delays. thank you in advance

Re: problem of a deployment in tomcat server

Gerben Jongerius10-May-12 9:20

Gerben Jongerius

10-May-12 9:20

The build script is already telling you what you should be doing next. Locate and look into the catalina.out file for more details as to why the web app failed to start.

As to where the catalina log files are, that depends greatly on what type of Tomcat install this is. If it's integrated in Netbeans then it's located in the .netbeans/7.1.1/apache-tomcat/logs.

If it is a debian / ubuntu based linux its found under /var/log/tomcat

In either case the catalina log will show the root cause of the failure to start. But it's most likely something in the web.xml that is wrong.

Cloud Computing For Agent Based Urban Transportation System

cloudagent9-May-12 8:25

cloudagent

9-May-12 8:25

Hello there,
Above subject is my project topic.
So i need help for executing it properly on my Windows XP system.

Installed Software.

1.JDK
2.Tomcat

But i dont know how compile the code in eclipse.

Plz help me out.

Re: Cloud Computing For Agent Based Urban Transportation System

Richard MacCutchan9-May-12 9:04

Richard MacCutchan

9-May-12 9:04

cloudagent wrote:
Plz help me out.

Read the eclipse help pages which explain how to create and build a project; it is really quite simple.
When you have a more specific technical question feel free to come back for further help.

Binding 100,000 items to a list box can be just silly regardless of what pattern you are following. Jeremy Likness

Re: Cloud Computing For Agent Based Urban Transportation System

TorstenH.9-May-12 19:37

TorstenH.

9-May-12 19:37

http://tomcat.apache.org/tomcat-4.0-doc/appdev/deployment.html[^]

here you go. You need to deploy your project as a *.WAR file and then bring it to the tomcat. Don't forget to register it there.

regards Torsten
When I'm not working

Re: Cloud Computing For Agent Based Urban Transportation System

jschell10-May-12 9:33

jschell

10-May-12 9:33

cloudagent wrote:
But i dont know how compile the code in eclipse.

Hopefully either you have more than a beginner level of programming experience in java or have at least a mid-level experience in programming something like C++ or C#.

Otherwise in terms of what one might suppose "project topic" means you have bitten off more than you can chew.

If you do have that then it might help to note that you don't need eclipse to use tomcat.

Enrich result

RORY178-May-12 9:09

RORY17

8-May-12 9:09

i have ontology and i made a query on it in java with jena ,lets say that i search for "car" my request is how i retrieve all relations that related with "car"
note:i used wordnet into java but the result is so poor

Re: Enrich result

TorstenH.8-May-12 18:56

TorstenH.

8-May-12 18:56

Th project Jena Ontology API[^] has a documentation[^].

I bet your answer is in there.

regards Torsten
When I'm not working

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