Servlets :: Why Objects Stored In Session Should Be Serializable
Feb 5, 2015Why is it that objects stored in session object should be serializable?
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Copying Data Objects To Serializable Objects
Jul 27, 2014I am currently working on a project where I need to return data from a database over RMI to a client who requests it. Some of the fields in the Data Object can not be seen by the client so I need to create another object to send over the network instead. The method I use is this...
public static SerializableObject createSerializableObjectFromDataObject(DataObject dataObject){
SerializableObject serializableObject = new SerializableObject();
serializableObject.setField(dataObject.getField());
serializableObject.setAnotherField(dataObject.getAnotherField());
return serializableObject;
}
Is there a better way of doing this? I am creating many subclasses DataObject which all require this static method to be implemented and I can't push it into the superclass because each one needs custom behaviour.
Modify Values In Fields In Serializable Object Using Objects Set Methods Java
Dec 10, 2014This program is basically complete. It compiles and runs. It is a college course assignment that I pretty much completed but for the last part in which I'm suppose to change the values of all fields and display the modified values using a toString method. Modifying the values of the fields is where I am stuck. I don't think I need to create a new text data file to do this. The instructor only asked that all the values of fields be changed and this was the last part of the assignment so I don't think it involves creating additional ObjectOutputStream and ObjectInputStream objects. I'm getting a NullPointerException error on line 161.Here is the code. I'm also including the input data file.
//create program so that objects of class can be serialized, implements interface Serialiable
//create constructor with 4 parameters with accompanying get and set methods, Override toString method
//create text file with 5 records, create Scanner object,ObjectOutputStream, and ObjectInputStream
//create new ItemRecord object, change values of all fields in ItemRecord object using object's set methods
//modify ItemRecord object using toString method
[hightlight =Java]import java.io.Serializable;
public class ItemRecord implements Serializable
[Code] .....
This is the error message:
----jGRASP exec: java ItemRecordReport
Item Cost Quantity Description
Number
A100 $ 99.99 10 Canon PowerShot-135
A200 $149.99 50 Panasonic-Lumix T55
A300 $349.99 20 Nikon- D3200 DSRL
A400 $280.99 30 Sony- DSC-W800
A500 $ 97.99 20 Samsung- WB35F
Exception in thread "main" java.lang.NullPointerException
at ItemRecordReport.main(ItemRecordReport.java:161)
----jGRASP wedge2: exit code for process is 1.
----jGRASP: operation complete.
Here is the data file:
A100 99.99 10 Canon PowerShot-135
A200 149.99 50 Panasonic-Lumix T55
A300 349.99 20 Nikon- D3200 DSRL
A400 280.99 30 Sony- DSC-W800
A500 97.99 20 Samsung- WB35F
Here is the data file for the modified field values.
B100 98.00 10 ABC1010
B200 97.00 15 DEF1020
B300 96.00 10 GHI1030
B400 95.00 05 JKL1040
B500 94.00 01 MNO1050
JSF :: Viewstate Stored In Session And Values Of Input Fields
Sep 11, 2014Many times I have read that JSF stores de view state in session and one of the things that are stored are the values of the form fields, right? But these input field values are not stored in session, I mean, they depend of the scope of the managed bean attached to the view. If I have a view and its attached to a view scoped bean with properties for the form fields, the values will dissapear if I go to other view because the bean is view scoped so I cant say the values of the form are stored in session, right?
View Replies View RelatedServlets :: Can Access Session Object Even Session Is Time Out
Jun 4, 2014Can 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 RelatedServlets :: Updating Session Value But Same Session In JSP Page Not Updated
Jul 8, 2014I 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..
Servlets :: How To Use Session
Apr 16, 2014I'm trying to go back to basic and strengthen some of my foundation. I'm wondering what kind of data would be appropriate to be stored inside a session? My app is a web app where all the users are the employee of a company. So it's an web-based app that keeps track of stock movements, purchasing and sales order (standard distributor company). The web app interacts strictly with employees, so no public facing app (yes, that's right, no shopping cart). So, in this kind of web app, what kind of data that by storing it to session.
View Replies View RelatedServlets :: Same Session On Two Separate Web Applications?
May 18, 2014We have this website that is run on two web applications. The first web application hosts the home page and clicking certain links in the home page would forward it to pages of the second web application where certain functionalities can be done. Now, there has been an initiative to redesign the site to have a login page and only logged in users could browse it. This would mean a login page being created in the first app, and when links to the second application are clicked, the pages are supposed to forward to it with the same session of the user that logged in.
We have already creating handling to pass the session from the first app to the second. Logging out from the first application would also invalidate the same user session in the second application. My questions is, is this a bad idea? would it be better to combine the two apps even if it would mean a huge impact?
or is there are better way to do this? like set it in web.xml. I have read that you cannot use two context for it.
Servlets :: Cannot Serialize Session Attribute
Jan 11, 2015I am getting following exception.
Jan 11, 2015 10:08:23 PM org.apache.catalina.session.StandardSession writeObject
WARNING: Cannot serialize session attribute cart for session 2F9FF7A5ABC3620BD5B3BC0C4D46C558
java.io.NotSerializableException: org.apache.tomcat.jdbc.pool.DisposableConnectionFacade
at java.io.ObjectOutputStream.writeObject0(ObjectOutputStream.java:1183)
at java.io.ObjectOutputStream.defaultWriteFields(ObjectOutputStream.java:1547)
at java.io.ObjectOutputStream.writeSerialData(ObjectOutputStream.java:1508)
[Code] .....
Servlets :: Getting Data Anywhere By Storing In Session
Jul 22, 2014I've sample code of jsp and servlets. Below is my code.
Index.html
<!DOCTYPE html>
<html>
<head>
<meta charset="ISO-8859-1">
<title>Insert title here</title>
</head>
<body>
<form action="AnnotationServlet">
[code]....
Now I want to store those username and age(in .html) somewhere and I want those information in welcome.jsp. Now, I'm storing all those in session itself(In doGet method(servlet)).
2 Doubt) Also, when I get the session in servlet HttpSession session = request.getSession(); line No. 27. The session value is org. apache. catalina. session. StandardSessionFacade@69a8bf4f...I'm expecting that session is to be empty. Because, I dint store anything until that line.
Servlets :: Restoring Session Variable After Timeout
Oct 17, 2014My application uses Struts and IBM Web application Server. I have a question regarding session management. I have a variable stored in session scope, i.e. the name of the client. it is a intranet application. Now whenever the user leaves the browser screen for a long time, the session times out and losses the name of the client.
How to restore the variable after the client comes back and starts using the browser and refreshes the screen and starts using the application. I want just the browser to remember the session variable i.e. "name" of the client.
Servlets :: Intermittent Loss Of Some Session Attributes
May 21, 2014Session attributes after logging into web-app:
Session Attributes
thisUsersAllowedRoles=45
username=hw
authenticatedUser=org.hw.client.payroll.model.User@2c8a09da
supervisorCode=
authenticated=true
[Code] ....
Every now and then while debugging I lose session attributes:
Session Attributes
thisUsersAllowedRoles=45
username=hw
supervisorCode=
authenticated=true
[Code] ....
The authenticatedUser and menu attributes are gone. I never know when it's going to happen so I can't trace it. Any guesses why those type session objects would die?
I attached an image of what menu object looks like.
Servlets :: Unable To Understand JSP Session Concept
Mar 10, 2015Any brief introduction about session in java....
View Replies View RelatedServlets :: Session-timeout Not Fully Working
May 9, 2014in my web.xml my session time out is working but not fully working in my ui i use tiles , i have 5 clickable side panels i try to set timeout for 1 minute or 10 minutes for testing after the time is timeout this what happen working refresh the page after time out = working ,directed me into log in page which is correct.i have 5 clickable side panel in my page after timeout when i click the first 2 in side panel tabs it directed me into log in page which is also correct not working after the timeout when i navigate the page i click the other 3 side panels i can still navigate into the page but when i click the first 2 side panel it directed to log in page w/c is correct but can still navigate the page the other 3 side panels
issue : my session timeout is not fully working on my page.
<session-config>
<session-timeout>10</session-timeout>
</session-config>
Servlets :: Why Session Not Type Casting Into String
Oct 17, 2014why my session not type casting into String? I'm placing that code below where problem arised.
HttpSession hs1=request.getSession(false);
out.println("hi");
String t1=(String)hs1.getAttribute("name");
out.println("hi "+t1);
in my above code first "hi" is printed successfully but next statement arises type cast exception.
Servlets :: How To Check For A Session As The User Goes Through Different Pages
Mar 18, 2014I have a question about how to check for a session as the user goes through different pages. I am using Java beans and EL to pass data from page to page but I cannot figure out how to check for a session on the pages without the use of a scriptlet with an if else statement in it.
I do not want the user to be able to access any pages unless they are logged in. With a scriptlet, I can create a statement that says if session exists show name else redirect to login page.
From what I have read and what some of the wonderful members here have told me, scriptlets are a big no no these days. So, how do I do these without the use of a scriptlet?
Servlets :: Session Attribute Keeps Reverting To Declared Value
Dec 29, 2014Being new to java I am a bit lost as to why my session attribute for this banking app wont add the deposits to the session var... it just keeps going back to the amount I set it to originally - so if I set the beginning balance to 3000 then deposit 100 it becomes 3100, but if I then try deposit another amount eg. a extra 200 it becomes 3200 not 3300 like it should be !!
import javax.servlet.*;
import javax.servlet.http.*;
import java.io.*;
import java.util.*;
import java.net.*;
import java.text.DecimalFormat;
public class SessionBank extends HttpServlet
[Code] .....
Servlets :: Two Application Servers - Session Replication
Jun 20, 2014My application has two Application servers, App1 and App2..
We are using weblogic 8.1 Application server
There is session replication done in weblogic.xml file .
<session-descriptor>
<session-param>
<param-name>InvalidationIntervalSecs</param-name>
<param-value>1</param-value>
[Code] ....
The application works fine but currently there is data getting replicated among different users. Is it the problem of session data getting merged with other session data or is it server cache not getting cleared or is there any setting to be changed in weblogic application server??
Servlets :: Difference Between JSESSION ID / Cookie And Session
Jul 28, 2014What is the difference between JSESSION ID and Session?I red THIS blog, I got the explanation but I'm actually confused about JSESSION ID and Session.. In that blog, they told about JSESSION ID cookie. then What is the difference between JSESSION ID and Cookie?
View Replies View RelatedServlets :: Java Class - Session Variable Error
Dec 14, 2014My dynamic web project has a java class that captures a session variable with the following code.
HttpSession LoginSession = request.getSession();
String VAR = LoginSession.getAttribute("myVar").toString(); //This is the row 127
If i test the app in local (Mac + Java 1.8 + Tomcat 8) all works. In my remote cloud server (Ubuntu 14.10 + Java 1.8 + Tomcat 8) all works, except this class, that has this code. I copy the complete error here. Note that the row 127 of the error message is the second row of the previous code; and, if i comment this row with // and assign a fix variable all works. So, the problem is that 127^ row.
14-Dec-2014 08:15:23.923 SEVERE [http-nio-8080-exec-14] org.apache.catalina.core.StandardWrapperValve.invoke Servlet.service() for servlet [srvNavigation.SrvPT] in context with path [/myapp] threw exception
java.lang.NullPointerException
at srvNavigation.SrvPT.doGet(SrvPT.java:127)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:618)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:725)
[Code] ....
How can i solve the problem?
Servlets :: Disabling Cookies In Firefox Does Not Create Session
Mar 4, 2014I'm experimenting the basic concepts of Servlet technology with my below simple setup.
I have a welcome.jsp defined under webContent in eclipse and my welcome.jsp looks like
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1" [b]session="false"[/b]%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
[Code] ....
Now I have few questions based on the above setup
1) As you see session="false" in jsp, and when I used scriptlet like <%= request.getSession(false) %>, I see "null" being printed but if I use pageContext.request.session.id, the session is not null. How does session = "false" influences scriptlets and implicit objects and why the behavior is different
2) If session really exists, even when session=false is used, when I disabled cookies in FireFox browser and click on "click Me" hyperlink, the control goes to Controller, but in the servlet, I see 'No Session Created" being displayed. Which means session was not created and probably because I used false is getSession(false). But if I enable cookies, with the same setup, I get Session ID = << some value>> being printed and this is same as the session what printed through pageContext.request.session.id in the jsp.
So when cookies disabled, how can pageContext.request.session.id actually printed session id , but not in servlet and when cookies enabled, the same session id is displayed in both cases.
My question is why there is no impact in jsp, when cookies are disabled.
Servlets :: How To Know Which Class Will Implement Which Session Listener Interface
Jan 23, 2015how it is decided which class will implement a session listener interface? Which class will implement HttpSessionListener? Which one will implement HttpSessionActivationListener, HttpSessionBindingListener or HttpSessionAttributeListener?
View Replies View RelatedServlets :: Create A Session After Login And Invalid It After Logout
Apr 1, 2014How can i create a session when i loged in and how can i invalid it when i logout?
View Replies View RelatedServlets :: How To Get Attribute From Session In Regular Java Class
May 21, 2014i have file index.jsp , that approach to reguar java class and call function . in that function i want to get attribute from session like this :
List<Coupon> couponsList = (List<Coupon>)request.getSession().getAttribute("listOfCouponsThatNotExpired");
because this regular java class i get error message ,how to solve this ?
Servlets :: Shopping Cart Session Is Not Working Properly
Jan 4, 2015I am adding my shopping cart in session like bellow in servlet
HttpSession session = request.getSession();
session.setMaxInactiveInterval(60*30); // 30 minutes
if (session.getAttribute("cart") == null){
session.setAttribute("cart", new ShoppingCart());
}
cart = session.getAttribute("cart");
I seems if more than one person accesses it from server, if they items in the shopping cart, all the product is added to a single session. I mean if i added 4 items first and other person adds 2 items, second person sees 6 products in his cart. Where am I going wrong?
Servlets :: When HTTP Session Object Created In Web Application
Jul 17, 2014When does HTTP Session object is created in web application. Suppose I have a website. Home page of website is HTTP page which contains details of company and link to Login page.
Consider below mentioned user journey as scenario:
a. user arrives at home page of website
b. user click on Login page
c. user fill in login details on login page and click on Submit
d. user is successfully authenticated and authorized from back end
e. User specific page is shown
f. user click on logout link
g. user is successfully logged out from website
h. user is redirected to home page
i. user closes browser
In the above mentioned user journey,
a. at which step does HTTP session starts (means at which steps does HTTP Session object is created ? )
b. at which step does HTTP session ends ?
In case required, assume tech stack to be Java 7, Servlet 2.5, JSP, Tomcat 7, Apache web server (for static web contents).....