I am making a Java project using Eclipse,oracle 10g and Apache tomcat.
Now my problem is that I cant create a session for the users. I have coded on jsp pages mostly.
Session creation using HttpSession through servlets or jsp
Coding a web application using Java 6. Try to implement the session timeout for users.
In the web.xml, I added:
<session-config>
<session-timeout>480</session-timeout> <!-- jsp will expire in 8 hours -->
</session-config>
Now, during the runtime, if a user does not touch the jsp page for 8 hours (after the user has signed in), the session timeout mechanism will kick in. At that point, the server side will automatically execute:
rd = req.getRequestDispatcher("/signin.jsp");
So that the user will have to re-sign in, before continue the work.
How can I achieve this goal?
May be I did not understand the meaning and usage of attribute "session" in page directive. My understanding is if session=false, in page directive, then the JSP page will not participate in the session. However, I have my welcomepage as below:
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1" session="true"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
........
.......
<%= session %>
<c:out value="${pageContext.request.session}"/>
if I choose session=true, then both ways of accessing session works , which means the JSP page participated in the session.
But if I change the session=false, then <%= session %> fails, but <c:out value="${pageContext.request.session}"/> does not fail.
how can c:out still show the session, when session = false
Can I access the session object even session has been expired? I need to check whether session is expired or not for each request.The session invalidation is set null the session object. What I concluded, session time out I can access session object but session invalidation I can not access session object. How can I find the session time out by using session object?
View Replies View RelatedI have 2 war in 1 EAR.
War A corresponds to UI
War B corresponds to Rest
1) From War A, I login to the application and then fetch some users that is a rest call. I get the response back from rest in json form that ui consumes and display the data on page.
2) Now I click on the logout link from ui jsp. This logs out the session from Ui. I use <form data-dojo-type="dijit/form/Form" based logout.
3) I then go to the proxy (using burp) and manually request the rest call which I made in step no 1), the rest gives the response back with the same json object returned in step no 1) This shows that the logout action on step 2) is invalidated the session from War A (ui war) but the session or cookie based from WAR B (rest war) is not invalidated.
Expected outcome:After I Logout from War A(ui war), the session must also get invalidated from war B (rest war) and manually request from proxy should not get the same response object as received in step 1)
I am developing a e-commerce college project, here i add the items in the cart(a div tag in the jsp page) via servlet by creating sessions,
flow control: shopping jsp (when user wants to add an item in the cart) --> item servlet (which is used to create session and synchronized it) --> cart servlet(which is used to add items in the arraylist and show them in the shopping.jsp's div tag + it also sets the total purchase amount in the session variable "totalpurchase")
now after that user wants to proceed to checkout, here i use the onclick event to check the minimumshopping amount must be less than the totalpurchase (totalpurchase which i had setted in the session),but my jsp page is unable to rechognise the updated value of the totalpurchase, yes, if i reload the page, it rechognises the new updated value of the totalpurchase? but i want it to rechognise the updated total purchase value, without reloading he jsp page..
I know I'm missing something simple, but not sure what. When running the following I have to enter the name of the output file twice.
import java.util.Scanner;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
public class IODemo {
[Code] ....
I am trying to create a Android game. The game is a card game, where each card has a different action and has a different effect. My first thought was to create a Card class and somehow dynamically change the action method for each instance. However after a little bit of research it seems that may be too difficult. A different idea is that I create a class for each different card, and therefore can define the action method different for each one. However currently there is at least 300 cards and therefore I would need 300 different classes, which seems excessive.
View Replies View RelatedI'm making a code for a log in system that allow me to verify if username and psw are correct (using a file txt as refer), and then i will add maybe the possibility to sign up.
The fact is that I want this kind of formatting on the .txt
username psw
username psw
username psw
...etc
So I have to read the lines and split to the " " and compare the insert data and the read data.
Here is my code, it star but give me this error when i insert any word
XML Code:
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 1
at prova.main(prova.java:20) mh_sh_highlight_all('xml'); Java Code: import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;
public class prova {
public static void main(String[] args) throws FileNotFoundException {
[Code] .....
I am creating a simple tiled minecraft like game in java, but i dont know how to make the game loop.Here is the source:
package net.pltformgame.main;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;
import javax.swing.JFrame;
public class main extends JFrame implements KeyListener {
[code]...
I really dont know how i make the jump or the game loop.
How could we create excel sheets(xls) in java?
View Replies View RelatedSo, I've been working on creating a text-based game engine that would create games similar to Achaea. It's been working pretty well so far. I just finished creating a great mapping system, but now I've run into a problem. I have a mapping system, but actually creating a map would prove to be quite a lot of work. Each location that the player can be inside of has a name, description, map symbol, and an array of the things inside of it. How can I make some sort of map creation program or something so that I can create my maps more easily?
I thought perhaps making a constructor that accepts a list of files, the first containing a table of strings for the names, the second containing a table of strings for the descriptions, etc.; but it seems that would be quite tedious and may be more complex than actually just hard-programming maps.
I have just started to learn Java and have come across a small bump in the road, In the book I am reading it shows an example program using java.io.File with the line File javaFile = new File("test.txt");
The program then goes on to ask if you would like to delete the file with a small do while loop.
Anyway, try as hard as I can I cannot located the test.txt file on my system! is there a reason for this? The program runs fine and has no errors and if I manually create the txt file it will delete it, but it doesn't seem to create the file in the first place.
Why the file is not being created?
Now, I would like to properly stop the server. For that, I can do server.stop(); . However, this does not work since the object server is not public, it is contained within the public pc_proxy class.How do I do that?
Java Code: import java.net.*;
import java.io.*;
import com.sun.net.httpserver.*;
import java.util.concurrent.Executors;
import java.lang.reflect.Array;
[code]....
I have a couple of objects, which I will call height and width. The latter may depend on the former and I access them through an interface:
interface Height
{
double getHeight();
}
interface Width
{
double getWidth( Height height );
}
I then have something I will call a RectangleMaker, which represents some set of rectangles that can be made. It takes a list of heights and widths and keeps track of which ones have been selected and which ones can still be made. For example, the possible heights might be 2 or 3 and the possible widths 3 or 4. It needs to determine if it can make a rectangle with a specific area and if selected to make that rectangle, disallow any other heights. So if I said, you are in charge of 2 x 3 rectangles, it could still potentially also make 2 x 4 rectangles, but 3 x 3 rectangles would no longer be an option. For the most part I think these details are irrelevant to my question, which is really about organization and assignment of responsibilities.
interface RectangleMaker
{
void setHeights( ArrayList<Height> );
void setWidths( ArrayList<Width> );
boolean isAreaAvailable( double Area );
void selectDimension( Height height, Width width );
Height listAllowedHeight();
ArrayList<Width> listAllowedWidths();
}
Now I have a new requirement. The lists of heights now need to be associated with a source, as do the widths. I should keep track of a list of RectangleMakers and pick the 'most appropriate' one for a particular area. The rule is to sort first on the height source and then on the width source and the first one able to handle the area, gets the job. So I created two enums heightSource and widthSource and had RectangleMaker implement Comparable, so I can make an ArrayList<RectangleMaker> and sort it based on the rules. Then I traverse the list and the first one that returns isAreaAvailable() true gets the job.
The final bit is that these sources also imply a specific set of Heights or Widths. How I get that set varies, it may be a fixed value or values, or might be read from a file. So in principle I could have:
ArrayList<Height> buildHeights( RectangleMaker.SOURCE source )
{
switch ( source )
{
}
}
and have a lot of specific code that builds each list by whatever method is appropriate. I still need to deal with the fact I might need additional information to build the lists. For example, one source might require a min, max and increment and another might require a file name. So I started working in the direction of more interfaces.
interface HeightList
{
ArrayList<Height> getHeights();
RectangleMaker.Source getSource();
}
I am not totally comfortable with my enum lists. They solve the sorting problem, but I am not exactly sure which class should define them. Right now they are defined by the RectangleMaker. I would need to update this class every time I added an implementation of HeightList or WidthList.
I was also thinking that since the list is built from a specific source, that source should be associated with the list. That would lead me to make this change:
interface RectangleMaker
{
void setHeights( HeightList heightList );
void setWidths( WidthList widthList );
boolean isAreaAvailable( double Area );
void selectDimension( Height height, Width width );
Height listAllowedHeight();
ArrayList<Width> listAllowedWidths();
}
It seems maybe there should be a factory in here somewhere, but this is where I am having trouble sorting out exactly who has what responsibility. I can do this sort of thing with my HeightList interface:
class SpacedHeight implements HeightList
{
int start;
int end;
int step;
ArrayList<Height> heights;
RectangleMaker.SOURCE source;
[Code] ....
Should I be thinking of putting one more layer over all of this? What complicates my thinking are two things: multiple instances may have the same source and some of these instances are dynamic. For example, two SpacedHeight instances may have different ranges, but they are both SpacedHeight and it doesn't matter which gets picked first. Exactly what SpacedHeight instances get created is determined by prompting the user for the values. If the heights come from a file, every instance would be associated with a different source and the file names would be hard-coded.
I think I want to make a HeightFactory and I think then it would make sense to move my enum definitions there. I see how I would do that if I could hard-code a specific instance of a HeightList with a specific enum. I am less clear on how to handle the case where the factory needs different parameters for different HeightList implementations.
I am working on a UI in JavaFX and create several instances of a custom control class. The control consists of a Pane which wraps several other containers, one of which contains a Circle shape.
At one point, I instance this control and access the Circle shape directly. I transform it's center coordinates (which are always {0.0, 0.0} ) to Scene coordinates. The problem is, the transformation always yields coordinates that correspond to the upper left corner of the control's root pane.
In other words, it's as if the Circle is positioned at the upper left corner of the custom control (when, in fact, it's positioned near the lower right corner).
I have other instanced controls already in the scene, and they do not have this issue - converting the Circle's coordinates to scene coordinates works as it should.
It seems obvious that I'm accessing the Circle too soon - that perhaps the scene graph hasn't been fully traversed for the control and the Circle's position within the control's hierarchy hasn't been updated. I've verified that my attempt to access the Circle's center coordinates occurs after the control's initialize() method is executed, so how to ensure the control's scene graph has been fully updated before I try to manipulate the control...
I'm trying to write a transparent proxy like polipo. Polipo is written in C and I want to have the same result in java.
A simple program that can filter/monitor all connections created and closed by the browser.
To do so, I've chosen to work with sockets, because that's the only way i know to read and write raw data to and from the browser in a completely transparent way.
In this moment my code reads and writes every couple of request/response but I've noticed profiling it that the time needed to create the socket is a bottleneck.
Using URLConnection to create the same connection I need much less time than sockets.
When socket creation implies 50ms URLConnection implies only 1ms.
I have my code in 3 different files using encapsulation (Data hiding) and i have 1 problem at the very end of my code in my if and else statement (very bottom) when trying to call the classes from the other 2 documents. I will put the code in 1st document to 3rd document.
// FIRST DOCUMENT
public class CollegeCourse { //class name
//variables
String deptName;
int courseNum;
int credits = 3;
double fee;
[Code] ....
UPDATE: error message is
UseCourse.java:24: error: cannot find symbol
LabCourse lc = new LabCourse(department, course, Credits);
^
symbol: variable department
location: class UseCourse
UseCourse.java:24: error: cannot find symbol
LabCourse lc = new LabCourse(department, course, Credits);
[Code] ....
4 errors
I have the following unit test that gives me a null pointer exception. The debugger goes to the finally block right after the line that creates a connection factory. Here's the test:
@Test
public void receiveMessage() throws Exception {
MessageConsumer consumer = null;
ConnectionFactory connectionFactory = null;
Connection connection = null;
Session session = null;
Destination destination = null;
[code]....
How can a pop up trigger from java web application to all active users to broadcast something?
View Replies View RelatedI'm doing a problem where I convert users input for the date (MM/DD/YY) into a written out date and year. That part is fine. The part I'm struggling with is then indicating what day that is in that year. how to use the user inputted MONTH, DAY, and YEAR to then get the day of year.
import java.util.Calendar;
import java.util.Scanner;
import java.util.regex.MatchResult;
import javax.swing.JOptionPane;
public class ConvertDate {
[code]...
I have to design/develop a module in java eg. Login. This module can be accessed by multiple concurrent users say 200, 500, 800 etc.
How such type of modules can be designed in such a way that it can perform successfully.
What are the main concepts at code level / Infrastructure level which we should take care while designing such modules.
What should i do to create a JSP page that can be visible to some specific user's.
View Replies View RelatedCan method variables be shared between users?
I was asked this on an interview and I didn't know what to make of it.
Question : What would you do block a user if he fails to login in 3 consecutive attempts ?
My Answer : I will make use of Session object, so that server could identify that all 3 requests came from the same system.
Dont know if i am right .
I have created this project and want to be able to add new members to my members arraylist, store the input in a .txt file and load the new members after closing and opening the program.
[URL] .....