JSP :: Java Server Sent Events Not Working Correctly
Oct 10, 2014
Code structure :
Server : Java Servlet
Client : Simple JSP
Communication : Server Sent Events every 1 second
Here is the problem.
My code needed the server to send updates every one second to the client as stated above. Hence, I added a while loop with a sleep of 1000 milliseconds in the servlet code as shown below. The following strange behavior is observed:
- While the server is sending updates to the client, and the client window closes by mistake, the server does not stop sending updates It continues sending the data.
- When the client is re-opened, it sends data much faster (almost double). For example, the server sends 60 seconds worth of updates (60 updates) in just 25-30 seconds. The server sends faster updates not only for this round of updates, but also for any subsequent updates.
This server behavior is much unexpected. Am I writing the server side code wrong? I have looked around a lot and only found while loop method for modifying the server update interval. Is there any other method which I am missing?
I am currently writing two java classes (client and server). The client takes an input number form keyboard and sends it to the server. The server then multiplies this number by two and sends it back to the client. The numbers should also be printed to screen along the way, for example if I input the number 3 I should get
"From Client: 3" "From Server: 6"
They should continuously do this unless a negative number is received by the client, say for example the number -3 is sent to the server and it returns -6.
The code I have for the two classes so far is:
import java.io.*; import java.net.*; import java.nio.ByteBuffer; import java.util.Scanner; class Client { public static void main(String args[]) throws Exception { DatagramSocket clientSocket = new DatagramSocket();
[Code] .....
Currently, when I run the program all I get is an output of the number first entered. I am aware it requires a loop but I don't know where and what the condition should be.
Also if I wanted to adapt this so that it would take the integer from client and subtract two at the server and return to client who sends back to server to keep subtracting two unless it reaches a negative number at which point the client will terminate the program - how might I do this.
I do realise there needs to be a while loop in the above code, but I wanted to test it sent the number from client to server and its not doing it. All I get is a print screen of 'enter number' and then the number I enter.
I am building a program that when you enter 1. it allows you to setup an item. However running my code my second if statement runs through.
import java.util.Scanner; public class InventorySystem { public static void main(String [] args) { Scanner input = new Scanner(System.in); int count=0; int inputEntered=0; int numberOfItems=0; double cost=0.00; String item; String description;
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MakeDB.java:
import java.sql.*; import java.io.*; public class MakeDB { public static void main(String[]args) throws Exception { Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); String url="jdbc:odbc:StockTracker";
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[Code] ....
Errors: Exception in thread "main" java.lang.Error: Unresolved compilation problems: The type Actions must implement the inherited abstract method ActionListener.actionPerformed(ActionEvent) event cannot be resolved event cannot be resolved at button.Actions.<init>(Actions.java:4) at button.Actions.main(Actions.java:9)
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for (Player player : this.getPlayers()) { if (player.getLocation().getX() == 10) { } }
I'm not sure as to how to use Events in place of a for loop. I've been thinking on this for days, but I'm still stuck. Any example of using an Event instead of a for loop?
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How do you test the events within an inner class using JUnit
// File: : events/SomePanel.java // Purpose: Show use of named inner class listener.
import javax.swing.*; import java.awt.event.*; class SomePanel extends JPanel { private JButton myGreetingButton = new JButton("Hello"); private JTextField myGreetingField = new JTextField(20);
[Code] .....
Code extract taken from: Java: Inner-class Listeners
Taking the above example, do I need to use myGreetingButton.doClick to trigger this event to test the respective variables/values being used ? Also the Actionlistener inner classes is private so doubt I can access this from JUnit Test class.
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I've read How to integrate javaFX gesture management in a complex Swing application? and it seems that "there is no gesture recognition in a JFXPanel".
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Zip Code:
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