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Hi, I have two files one - client side in Java script, the other in Java - server side ..
I can not send and receive messages What is the problem? Thanks
Js:
<!doctype html>
<html>
<head>
<meta charset = "utf-8">
<title> Wiki Project </title>
<script type = "text/javascript">
window.addEventListener("load", onLoad, false);
function onLoad()
{
var ws_address = "ws://0.0.0.0:8090";
var socket = new WebSocket(ws_address);
socket.onopen = function(event) {onOpen(event);};
socket.onclose = function(event) {onClose(event);};
socket.onmessage = function(event) {onMessage(event);};
}
function onOpen(event)
{
alert("OPEN Connection");
}
function onClose(event)
{
alert("CLOSE Connection");
}
function onMessage(event)
{
alert(event.data.toString());
}
function insertMessage()
{
socket.send(document.directing.message.value);
document.directing.message.value = "";
}
function viewMessages()
{
socket.send("@View@");
}
function deleteMessage()
{
socket.send("@Delete@");
}
</script>
</head>
<body>
<form name = "directing" method = "post" action = "javascript:;">
Write a message:
<input type = "text" name = "message" size = "50" maxlength = "50" />
<input type = "button" name = "add_message" value = "Add to server" onclick = "insertMessage()" />
<input type = "button" name = "view_messages" value = "view messages from server" onclick = "viewMessages()" />
<input type = "button" name = "delete_message" value = "delete message from server" onclick = "deleteMessage()" />
</form>
</body>
</html>
Java:
package com.mycompany.wiki_project;
import io.vertx.core.Vertx;
class VertxServer
{
private static int place;
private static String store_in_server[];
private static String message_from_client;
public static void main(String args[])
{
place = 0;
store_in_server = new String[50];
Vertx vertx = Vertx.vertx();
vertx.createHttpServer()
.websocketHandler(ws -> ws.handler(ws::writeBinaryMessage))
.requestHandler(req ->
{
req.handler(buffer ->
{
message_from_client = buffer.getString(0, buffer.length());
switch (message_from_client)
{
case "@View@":
for (int i=0; i < place; i++)
req.response().write(store_in_server[i]);
break;
case "@Delete@":
place--;
break;
default:
store_in_server[place] = message_from_client + "\n";
place++;
break;
}
});
}).listen(8090);
}
}
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You are trying to send to an invalid address.
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How do I write this?
I need them both to listen to Port 8090
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The port number is fine, but you are using the IP address 0.0.0.0.
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i use
var ws_address = "ws://" + document.location.host + document.location.pathname + ":8089";
not work
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Try connecting to the server code through a browser to see if it will accept a normal request. I do not know Vertx so you may need to use their support lines for help.
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I just started to learn Java Servlet, but I can't really make it work.
I'm trying to do something basic first, to see how it works, read data from a form, print the 2 values to in the console and then redirect the user to another page.
Using the following code (what I though it will do it), redirects me to another page that doesn't exist "/Testare?firstName=Example+First&lastName=Example+Last"
I'm using Apache Tomcat for server.
The form is on Home.html:
<form action="Testare" method="GET">
First name:<br> <input type="text" name="firstName"><br>
Last name:<br> <input type="text" name="lastName"><br>
<br> <input type="submit" value="Submit">
</form>
Testare servlet doGet trying to print and then redirect to "Test.html":
System.out.println("First name: " + request.getParameter("firstName") + "\nLast name: "
+ request.getParameter("lastName"));
response.sendRedirect("Test.html");
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Your question isn't clear.
If the redirect page doesn't exist then it isn't going to work regardless of what you do.
If the initial page doesn't exist (it is not serviced) then it will not work regardless of whether the second page exists or not.
Redirection is handled by the browser not the server.
Here is an example which should have a working redirect.
Login and register form in one page in servlet[^]
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I'm not entirely sure, but I think the problem was from web.xml. Now the problem is gone.
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I am looking for the sample code which helps me to read the raw bytes from wireless modem connect via the USB port of a laptop and test it on IntelliJ.
Suggestion on this will be a great help.
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Google is the place to search for sample code. And as it is a hardware device you may find something is already provided by the manufacturer.
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Thanks, I am searching on google also but can you give some theoretical description about to read the Raw data in HEX form by using java code?
I am working on a project in which I am trying to create the software which sends the data on google sheets.
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Sorry, but I have no idea how this device works so it is impossible to give a suggested answer. As I said you should check what supporting software is provided by the manufacturer.
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This device is connected with FTDI32 chip and being new in this I just want to read the values either in decimal or Hexadecimal format only?
I hope you might help to give some useful code to work with it?
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Sorry, I know nothing about that chip either. You really need to talk to the device manufacturer.
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1. Find an API. Ideally one for the modem, but if not one for USB devices.
2. Figure out the protocol for the modem. You can't 'read' anything until you establish a connection.
3. Write code to use 1 and 2.
4. Find something to connect to.
This is NOT how you should learn to use IntelliJ however. Find something easier to start with.
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I have a problem for RUN this code please help(Im working in Eclipse and i dont get any 'error report' but not works) (I dont know what i need any interface,abstract or method or something like that pls copy paste this code in your eclipse and help me ty )
package PaketX;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.event.ComponentEvent;
import java.awt.event.ComponentListener;
import javax.swing.JPanel;
@SuppressWarnings("serial")
class P06 extends JPanel implements ComponentListener {
int width = 800, height = 600;
Color AtaRasgeleRenk() {
int r = (int)(256*Math.random());
int g = (int)(256*Math.random());
int b = (int)(256*Math.random());
return new Color(r,g,b);
}
public P06() {
setPreferredSize(new Dimension(width, height));
addComponentListener(this);
}
@Override
public void paintComponent(Graphics g) {
super.paintComponent(g);
int i, j, m = 7, n = 9;
int x, w = Math.round((float)width/n);
int y, h = Math.round((float)height/m);
for(i = 0; i < n; i++) {
x = i*w;
for(j = 0; j < m; j++) {
y = j*h;
g.setColor(AtaRasgeleRenk());
g.fillRect(x, y, w, h);
}
}
}
@Override
public void componentResized(ComponentEvent e) {
width = getWidth();
height = getHeight();
}
@Override
public void componentHidden(ComponentEvent e) {}
@Override
public void componentMoved(ComponentEvent e) {}
@Override
public void componentShown(ComponentEvent e) {}
}
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Your post appears to contain code that is not properly formatted as code. Please indent all code by 4 spaces using the code toolbar button or the CTRL+K keyboard shortcut. For more editing help, click the [?] toolbar icon.
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Who are you directing this message to? There are more than 13 million members of CodeProject.
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Hi,
How can I connect to a website, and check if there are any elements that contain an given id, class or name. As for an example, let's say connect to https://www.google.com/, and check if this website has an element (input, div, image, etc) with id="anElement", or class="anElement", or name="anElement".
I have tried using the following code, but I'm getting from one error to another, which makes me think this isn't what I have to use, or I'm just doing it wrong.
URL url = new URL("https://www.google.com/");
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
Document doc = db.parse(new InputSource(httpURLConnection.getInputStream()));
NodeList noteList = doc.getElementsByTagName("anElement");
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You can check the existence of particular elements by reading the document surce. That should then help you to test your code.
Valentinor wrote: but I'm getting from one error to another
Unless you tell us what the errors are it is difficult to make any useful suggestions.
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Unfortunately I'm new to "web area", but I still have to learn it.
Quote: You can check the existence of particular elements by reading the document surce.
So, I take it that the combination of DocumentBuilderFactory + DocumentBuilder + Document was the right choice, no?
Quote: Unless you tell us what the errors are it is difficult to make any useful suggestions.
Well this one is a little more complicated. It is different from site to site (my best guess is the way they are made).
When I get pass the 403 error, I'm getting 503 (couldn't find a way to fix this one), and there are some websites where I don't get either but the last error:
java.io.IOException: Server returned HTTP response code: 403 for URL:
java.io.IOException: Server returned HTTP response code: 503 for URL:
[Fatal Error] :1:3: The markup in the document preceding the root element must be well-formed.
Exception in thread "main" org.xml.sax.SAXParseException; lineNumber: 1; columnNumber: 3; The markup in the document preceding the root element must be well-formed.
All these errors point to this line:
Document doc = db.parse(new InputSource(httpURLConnection.getInputStream()));
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All these errors are quite common and mean that the website cannot, or will not, provide you the web page that you request. Your code should first check the return status to see that you have received a 'good' page; see HTTP Status Codes — httpstatuses.com[^]. As I suggested before, you should first find a page that works, and look at the source to see exactly what gets returned to you. Remember, the data that is returned is controlled by the remote website and may not always be what you want, or think.
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Unfortunately, for my idea to work, I was going to need for this to work with every website. And most likely those websites that have this type of "protection" are the ones that my users were going to use.
Well, thanks for you help!
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