I have two separate applications who will access the same table in a database and the two application will update the table.
How can I make sure the integrity of accessing this table? Is it in the code or in the database level?
I'm writing my first bigger program (mysql connection and the first thing bigger than 300 lines ). What I'd like to do is to render data from MySQL using JTable - I managed to handle all the queries but I don't know how to update the table on screen. I've tried to use repaint() but nothing happened. I'm not posting whole code because you'll probably not interested, below are the most important things. I thought about using TableModel but how.
public class Main implements ActionListener{
JTable table;
public Main() {
JFrame frame = new JFrame("Frame");
frame.setLayout(new FlowLayout());
frame.add(table);
[code]...
I have a HSQLDB-database and the update syntax is as follows:
Java Code:
UPDATE table SET column = Expression [, ...] [WHERE Expression]; mh_sh_highlight_all('java');
Now I would like to update a column, with an inner join. Because inner join is not supported in this update-syntax I put the relationship in the where clause:
Java Code:
update table1 set rang=null where table1.column1 = table2.column1; mh_sh_highlight_all('java');
But HSQLDB is always saying to me that there is an syntax error: user lacks privilege or object not found: table2.column1
But I am 100% sure, that there is a table2 with the column1. I have no mistake in writing!
I have a need to refresh my database for every 15 seconds. I have to work with jsp ajax and jquery. For small amount of db entries it is ok but My application is going to handle huge records more than 20000. In my present scenario, Im forwarding request to another jsp page which communicate db and returns a table as result. Instead of this what are things I need to do?? This is just a sample application only. On success I am gonna implement using Spring, hibernate. So instead of table returning json or arraylist like that will work??
Here is my code:
## index.jsp ##
<!-- begin snippet: js hide: false -->
<!-- language: lang-html -->
<%@ page language="java" contentType="text/html; charset=ISO-8859-1"
pageEncoding="ISO-8859-1"%>
<%@ page import="java.sql.*" %>
[Code] .....
I'm getting ready to code a program that takes record of items loaned and return in a table. I want more than one user to access the program to be able to update the data in the table. For instance, if one user added 5 new items to the table, all other users would be able open the program to see a modified table with 5 new items. Was looking for some advice and was wondering if implementing a database would work best.
View Replies View RelatedI have 2 tables on 1 database
Table A, Table B
I need to evaluate a query by joining these 2 tables and then update the results in the 3rd table in another database. I need to use stateless session bean using JPA I believe. I need 3 Entities for each of the tables here.
I am trying to create an array list without using the built in arrayList class that java has. I need to start the array being empty with a length of 5. I then add objects to the array. I want to check if the array is full and if not add a value to the next empty space. Once the array is full I then need to create a second array that starts empty and with the length of the first array + 1.
The contents of the first array are then copied into the new array without using the built in copy classes java has and then the new array ends up containing 5 elements and one null space the first time round. The first array is then overwritten with the new array containing the 5 elements and the null space. The process then starts again adding values until the array is full which will be 1 more value then recreating the second array empty and the length of the first array + 1. This is my attempt at creating this but I have run into multiple problems where I get only the last value I added and the rest of the values are null:
public class MyArrayList {
public Object arrayList[];
public MyArrayList(Object[] arrayList) {
this.arrayList = arrayList;
[code]...
I have a strange behaviour when trying to update a bean. Here is the edit page:
<h3>Edit Post</h3>
<div class="row">
<h:form>
<div class="small-3 columns">
<label for="right-label" class="right inline">Title</label>
[Code] ....
Here is the bean class:
package com.airial.controllers;
import com.airial.domain.Post;
import com.airial.service.PostService;
import com.ocpsoft.pretty.faces.annotation.URLMapping;
import com.ocpsoft.pretty.faces.annotation.URLMappings;
import org.springframework.beans.factory.annotation.Autowired;
[code]...
postToUpdatet is always NULL. Why the title property is not binded ? What is wrong here ?
We 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.
I'm new to java and haven't develop any application before that... I need to develop an application through which i can send data from 1 computer to another computer. These communication in between the computers are those are under one router connection. Means they can connect even without internet access
Main concept is as follow
1. Java application on computer A [server side application]
2. Java application on Computer B [Client side application]
3. Java application on computer C [Client side application]
Now computer B and C communicate with computer A. but they don't know about presence of each other
I'm deployed application A and application B in TOMCAT server applications, the U1 user enters into the application A, he authenticates and generates a call to a page of the app B. As I was able to access the session of user U1 en A from B, it could have a single session.
View Replies View RelatedI have an application written in Java on the Linux platform. My application will work the following way:
User A will open application. User B will open application.User A will need to send User B a message but without a socket connection.User B will need to send User A a message but without a socket connection.The user should be able to identify the messages sent to each other.If User A reads user B's message the message will no longer be available in the channel of communication.If one user exits their application their message should be removed.User C should not be able to read user A and user B message (This is only via the application design, no real security here).Applications should be able to work on different machines however they will utilize a shared network mount to access files modified by each other.
I do have to note that the messages being sent is rather small and only 1 message is sent from each user, so in that regard I did not want to setup a client/server model to do this using sockets.
Basically I am looking for a similar concept as a message queue but more relevant to my requirements done in Java. What are some good options to use that will address some of my requirements? I have not touched Java in a long time and only have used it for certain usage so I am trying to get an idea of which current technologies are best for what I need.
I would like users in an application to be able to access and edit their user profiles (Application A). The problem is that the user objects (entities, dao, beans) are handled in a separate application (Application B) which is specifically for managing user accounts. Importing the java sources for App B into App A could be messy and might need configuration of the persistence unit and connection. I'm thinking it would be better to inject an EJB from App B to App A to query the user DB and return the results so a user profile form is rendered in App A.
I know how to inject EJBs within the same application, but I'm not so sure about how it's done across different applications or even if that's the most advisable way to achieve what I want. it's better practice to inject an external EJB into App A or simply import the classes from App B and use those.
@Stateless
public class UsersDaoImpl implements UsersDAO {
@PersistenceContext
private EntityManager em;
[code]....
I just installed java on my computer because i was getting messages that it was no longer there. And I figured out how to solve my problems on my browsers. but i don't see how to enable java in my applications on the hard drive. in particular, i want to use the database in open office but don't see how to enable it.
View Replies View RelatedBecause there's little information that actually explains application servers in the real world, For one domain at www.url.com:
- How many application servers are there if there are multiple applications hosted on this domain? Ie. url.com/app1, url.com/app2, etc.?
- How many web servers will there be?
- How would I make one physical server handle all requests for one of the above applications?
- How would one make static content a standalone application built with angularJS? Not static content served by servlets.
I question this as I have not yet succeeded in deploying a working ruleset for use with intranet based applications. I have verified the ruleset is working with external internet java apps so it is being deployed correctly just doesn't steer Intranet based apps to the correct version.
View Replies View RelatedGenerally sessions in web applications expire after a stipulated max inactive interval. To my knowledge primarily the reason is if the session objects are not invalidated they keep exhausting the memory. So my question is
A. Is there any other reason other why web applications timeout the user session after an inactive interval?
B. Social sites never timeout the user session even if you just leave them for the entire day. How do they manage sessions? Don't the active sessions exhaust memory on their servers or JVM to be specific?
I am maintaining an existing Java product (which has a HUGE code-base). I discovered that it is setting (and getting) two of its internal passwords as Java system properties, at no less than 4-5 different places (methods). Now, the problem is, the passwords are being stored as plain text in the Java system properties, and so, the same is visible to external entities, as the application is not using any Java Security Manager. For example, if the application (process) is running on port number 1234, we can run the Java command:
jinfo -sysprops 1234
to view both the passwords as values of the corresponding Java system properties. I wish to ask if there is any remedy to this without changing the existing code-base too much? The desired effect would be to "hide" the two Java system properties (denoting the two passwords) from all external entities.
It may be noted that introducing a Java Security Manager into the application may not be a solution, as if we revoke read permissions from the said two Java system properties using the Java Security Manager, the application codes which read those properties would crash. Same is applicable for storing the passwords in encrypted form, as that would crash all codes within the application which are expecting to read the passwords in clear text form.
To give a bit more context, the said two passwords we are storing as Java system properties are actually passwords to access two key-stores, and Tomcat requires that we store the said two passwords in plain-text format. Any workarounds, such that only Tomcat will be able to see the two passwords as-is, while they will be invisible to all other external entities?
Or, is there any way to place the said passwords in other in-memory locations (like static variables) which only Tomcat can (be made to) read instead of placing them as system properties which is exposed to anyone?
I have a problem with several java applications. When I start them Java wants to connect to the certificate authority, to check if the certificate is still valid and not on a blacklist.
The problem is: my whole internet is behind a password protected proxy. If I open my browser i get a windows with username and password. I enter it and internet in the browser works. But for Java it isn't working, because I see no point, where I can enter the password and username for the proxy. I can enter the proxy ip and port in the java settings, but not the password and username. So I get a error screen from java, telling me, that java could not connect. I can disable the check in the java settings, but I don't wont that.
Is there a way to tell java, that java uses my proxy with my password and username? I already googled this problem and found nothing except tutorials for connecting with proxy in the java code. But these applications are not from me, I can't change the code ...
How to define Cell in the table by table event?
I need to process one component drag to the table. I misunderstand, how I can see to which Cell fall the component. I tried to use Event and Mouse event handlers in my custom Cell, but they do not work. I can copy the drag event to the table and table handles it, but how to get needed Cell I cant understand.
This is my codes in a button that if I click it . that information will send to Jtable but the problem is the jtable is in another frame so how can i connect this ?
DefaultTableModel model = (DefaultTableModel)
new admin().tableBagtags.getModel();
if (txtName.getText().equals("")) {
JOptionPane.showMessageDialog(null, "Please fill out all fields.", "Error!", JOptionPane.ERROR_MESSAGE);
[Code] .....
I'm trying to add some mysql table columns to JSF table. And I'm getting error:
/index.xhtml: The class 'logon.User' does not have the property 'description'.
User.java
package logon;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
[Code]...
What step to know to develop software..
View Replies View RelatedI have a requirement to insert the data into xml file . I have used DOM class for doing this. Below is my xml file
<?xml version="1.0" encoding="ISO-8859-1" standalone="no"?>
<deployments>
<applications>
<application>
<name> PCMH</name>
[Code] ....
The thing is if SITA is the name then I have to insert component to the particular envi tabs , if DEVB is the component I have to insert the component there. How can I do this I have done some code its inserting the data at the bottom og the XML .
I have arraylist which is already set in controller side.
I need to update the same list(removing few elements in the list) in jsp based on few conditions like, the selected values in dropdown kind off.
How to update the list in jsp?. Is there any way to handle this using JSTL?.
Instead of using scriptlets, can i do this?
I am trying out jsp and servlets now for the first time. I have to insert two data, car code and car name into a mysql table. I got those details using jsp but if I use form, it redirects to another page for insertion. I want the data to be inserted and still remain in same jsp page. I am thinking of using onClick from javascript but as I googled this many places have said it is a bad idea to use jsp inside javascript. If so how can we insert data to mysql table without redirecting to another page?
View Replies View Related