Servlets :: How To Get Result When Website Initially Uploading Rather Than Pressing Button For Action
Oct 28, 2014
I am learning how to program in JAVA servlet+MySQL. Decided to make a simple program where it shows who is celebrating birthday today by retrieving data from database. At the moment I managed to get it working by loading a form.html and pressing the button in it which gets to the result.jsp and shows results there.
My plan was to get a list of people who are celebrating there birthdays initially when the website is loaded/being loaded, I mean when you enter URL into your web browser and you get it instantly in browser. Is there a way to do it the way I want (JAVA+servlet+MySQL) instead of pressing a button/link?
This is my first servlet program. I wanted to try a web application where "register" user module will be in servlet program.I can access my index.jsp but when I enter values and click submit.
I get "There is no Action mapped for namespace [/] and action name [RegisterUserServlet] associated with context path [/TrainingApplication]. - [unknown location]".
Here's my index.jsp file:
<%@ page language="java" contentType="text/html; charset=ISO-8859-1" pageEncoding="ISO-8859-1"%> <%@ taglib prefix="s" uri="/struts-tags"%> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head>
I don't get what I missed in the code. I used the example of changing the text of a button by clicking on it, but instead I also added a JLabel and tried to make the button change its text instead, but it didn't work. What did I do wrong?
I would like to know what is the best way to upload & download files using Servlets/Jsp's . In some websites I have seen example using third party API(by oreilly). Is it better to follow any third party or can we do it just by using I/O streams. What are the steps of uploading files. And where do we need to store files once the user uploads ,Database or server??
I am modifying existing code to display graph after pressing calculate button. The graph pop ups in new controller/window. The pop up disappears after closing the application entirely. However I have trouble figuring out if it is possible to close that old/previous pop up and new pop up appears when calculate button is pressed again. Or at least reuse the pop up to display a new graph.
public class AdamCalculationApp extends AbstractCalculation { /** * Does a calculation. */ public void calculate() { // Does a calculation control.println("Adam Calculation button pressed."); double k = control.getDouble("k value"); // String must match argument of setValue control.println("k*k = "+(k*k)); control.println("random = "+Math.random());
I have buttons created on a frame and then I register the listener from a controller in a controller-view relationship.
When I click the button on the face, the action never executes for some reason. I thought maybe there was a problem registering the listener but I can call the buttons doclick() method and it executes as it should. Perhaps I'm overlooking something really obvious here but I can't see it.
again, when i click the button nothing happens. but if i add the following code
btnEight.doclick()
the actionPerformed invokes in theController as I intended.
You can see the entire project on GitHub so you can see the full context. The controller class contains the listener and the view class contains the buttons.
I want to use this class and method with all of my buttons and text fields. My program contains 1 push button that adds questions and answers to a test, 2nd button that starts a test, a 3rd button that scores the test, and a text field that enters the user information. How would this work? I know how to create questions and answers, start a test, and score a test it's just a matter of how to implement the button and text fields. I'll post the code that I have done so far.
See:
private class ButtonListener implements ActionListener{ public void actionPerformed (ActionEvent event)
with all of my buttons and text fields.
import javax.swing.JFrame; public class TestingDriver { //----------------------------------------------------------------- // Creates and displays the main program frame. //----------------------------------------------------------------- public static void main (String[] args) { JFrame frame = new JFrame ("Testing Program"); frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
So that I can map the first request coming say www.xyz.net to my first page , it does the work but some of my css and images is not getting displayed .
So we need to inform all active users of the website that "Website will be down after so and so time for maintenance". This is how I see the implementation.
User can be in any part of the application. So any time user request comes to server, it goes through the controllers. I can write a method (and call from each controller) that checks if message needs to be displayed. Put that into application context and display it. Along with that I will also have a flag that keeps track that if the message has already been displayed or not (to the user). If message has been displayed, no need to call that method again.
find out why when I access the site for the first time, it loads a blank white page, but when I reload it, it forwards me to the home page as it should.
I doubt that the reason is nothing else than the code below (in the doGet method):
I suppose it's something with the session... because after I reload it, it works. But! When I close the browser and start all over again, the main page is white-blank again... And after a reload it works.
The exception:
SEVERE: Servlet.service() for servlet [first] in context with path [/MYSITE] threw exception java.lang.NullPointerException at controller.Controller.doGet(Controller.java:42) Line 42 of the Controller is "for (int i = 0; i < cookies.length; i++) {"
P.S. I cleared all the cookies, but the problem persists.Also, the first it loads, it prints in console:
"null been here 4!"
But, if I reload further, it prints:
"null been here 4! been here 2! No Email! Literally, doGet!"
I want to create a online examination system.i want to know to how to get questions 1 by 1 on the same jsp page and on clicking the submit button the result should be saved in database.
Its required to create a service to embed widgets on any foreign website(server), using servlets where i'll pass encrypted widgetId and in turn i will get html for displaying it on screen. Also a refresh button with the embedded widget is to be provided so as to fetch updated computed data. The point is that user should copy some html/script code and place it on his website.
I am thinking of following approach.An empty span with id, followed by a js script to make ajax call to the server to get widget HTML.
ResultSet rs = result.executeQuery(selectsql); int columns = rs.getRow(); while(rs.next()){
[Code].....
I can print out the result correctly, there are three rows of result from the database, but they are shown in one row on the browser, how could i show the result one row after another to let it looks pretty?
When I am invoking a servlet class file from my HTML file instead of displaying output in my browser it is downloading my output as a file..Why it is?..
My query retrieves more than 5000 records from Oracle database. I want to display the records 100 per page. I know it is called pagination. Any detailed styp-by-guide or tutorial or example available?
I've chosen to build a GUI that will initially display a window with 'x' number of buttons for different subject areas of physics (kinematics, waves, sound, circuits...etc). I would like to use an Actionlistener for each button so that when its pressed, the JFrame will extend a sidepanel or expand the JFrame with a new JPanel that contains variable Jtextfields so the user can enter data to calculate.
I'd like to know if its possible to do this with the JFrame or should I just open a new window altogether? I have some other features I plan to add to the program, but this is where I am right now.
how difficult is it to add a banner image and imageIcon? By banner image I mean create a Jpanel that will contain a header for the window and will have some cool physics jpg image.
I want to have a button in my Jsp's labeled "next" that takes me to the next JSP in a certain order. Imagine a book: every time you click next you go to the next page.
Each page is a JSP that is named "page#" where # stands for the number (page1, page2,etc).
I was structuring my app this way: one controller,one controllerhelper,multiple JSPs.
The "next" button in the JSP's would always have the same name as not to overcode in my controllerhelper with too many options for the button that was pressed.
So my idea was to retrieve the name of the current JSP and work the string in order to add a number (page4 turns into page5) and forward it through a requestdispatcher.
That is the problem as I am not able to get the name of the current JSP since the url changes after the first page to the servlet url.
I am having some troubles with a program fileviewer where you must be able to change font style and size when pressing JButton "Set font". I have solved the most of the program and every menu button is working but I don't know how to set in FileListener class method to change the font when running in main class. Anyway, this is my FileListener class
Java Code:
import java.awt.*; import javax.swing.*; import java.awt.event.*; import java.io.*; import java.util.*; import java.awt.Font; public class FileListener implements ActionListener
import java.util.Scanner; public class Program08 { public static void main(String []args) { char q; int quit = 0;
[code].....
I'm trying to get the code to repeat after the do part and before the while statement. Then press 'q' to quit the program. I had it right earlier by getting the program to repeat if you did a binary number, but I keep messing it up more and more.
table.addKeyListener(new KeyListener() { public void keyPressed(KeyEvent e) { if (e.getKeyCode()==KeyEvent.VK_ENTER) { model.addRow(new Object[]{"", "","",""}); } } public void keyReleased(KeyEvent e) { } public void keyTyped(KeyEvent e) { } } );
I've added JTable to JPanel and used DefaultTableModel. I have to add a new empty Row to table after i press enter key. But somehow I've not been successful so far.
i just started java and I'm trying to change the JLabel text by clicking on the JButton however it isn't working,
import java.awt.BorderLayout; import javax.swing.JFrame; import javax.swing.JButton; import javax.swing.JLabel; public class BorderLayoutJFrame extends JFrame { public static final int WIDTH = 400; public static final int HEIGHT = 400;
Problem: On the form window, after pressing the button, it doesn't give any error and doesn't give any output. It doesn't reply and i have to stop compiling to exit. Why does the IDE do that, is it about my Java codes or Form Window codes ? ( I have two classes named Lexical.java and window.java. Working with Eclipse)
Details: I am working on a project that makes Lexical and Syntax analiysis of commands written in SQL Language. My form is in the attachment. If will be necessary i'll put my codes too.
I want to create a simple ftp server which can upload and download a single file. i found code from google search but its showing error : connection refused . here is my server code n client code.
