I have downloaded the JTwain api and created/tested a java class to connect to my scanner, open the scanner UI and scan image back into java without any problems.
I then tried to create a JSP in tomcat where form action connects to servlet doPost method, which then calls the JTwain method.
The problem im getting is that instead of getting the kodak scanner window asking me to press scan the webpage just freezes. I put some system.outs to check where it freezes and it stops at 2 as if the kodak scanner dialog is displaying and waiting for me to press the scan button.
public static Image initScan(){
try {
Source source = SourceManager.instance().getDefaultSource();
System.out.println(1);
source.open();
System.out.println(2);
Image image = source.acquireImage();
System.out.println(3);
return image;
}catch(Exception e) {
e.printStackTrace();
return null;
}finally{
SourceManager.closeSourceManager();
}
}
I assumed it would work like any file open dialogue but clearly not, any suggestions?
I don't know anything about JTwain, but the JSP is executed on the server, not the client. And I suppose your Tomcat has no access to a GUI interface, which would explain that it can't open a Window. (Or it opens the window on the server, where you can't see it.)
Do you see anything in the server logfile?
Related
I use a java program for communication between a arduino board and a scratch file. The communication happen well. I use a user interface to start the communication where i have buttons called
connect
close and minimize
When the user clicks the connect button code will check the value in combo box and accordingly it opens the scratch file.
Once the connect button is clicked the control moves to the scratch application. After completing my work when i tried closing the scratch. My scratch application closes as expected but the control does not return to the user interface because of which i am not able to close the application and i close it in net beans forcefully. In the output screen i don't see build successful and instead i get build stopped. That is my process works perfectly until i give connect but once the button is pressed it is hanged up some where.
I tried making it as a jar file and running it in a different machine at that time i use end task in task manager to close the application.
private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {
if("Disconnect".equals(jButton1.getText()))
{
System.exit(0);
}
if(jComboBox2.getSelectedItem()==null)
{
System.out.println("Select one port");
}
else
{
Runtime r = Runtime.getRuntime();
try {
//this.hide();
//p = r.exec("C:\\Program Files\\Scratch 2\\Scratch 2.exe C:\\Users\\Admin\\Desktop\\fwdbckpwm12.sb2");
p = Runtime.getRuntime().exec("C:\\Program Files\\Scratch 2\\Scratch 2.exe C:\\Users\\Admin\\Desktop\\scratch files new.sb2");
//Runtime.getRuntime().exec("taskkill /F /IM <p>.exe");
//p.destroy();
//r.exec("C:\\Windows\\notepad.exe C:\\Windows\\ss.txt");
//this.setDefaultCloseOperation(EXIT_ON_CLOSE);
A4S a4sObj = new A4S(new String[] {jComboBox2.getSelectedItem().toString()}); //defaultline
//A4S a4sObj = new A4S(new String[]{"COM16"}); //addedline
//r.gc();
//this.setDefaultCloseOperation(EXIT_ON_CLOSE);
} catch (IOException ex) {
Logger.getLogger(serialportselection.class.getName()).log(Level.SEVERE, null, ex);
}
finally{
//p.destroy();
//System.gc();
// }
}
Here is the code i tried. But none seems to work.
Move all Process related work into separate Thread.
Use waitFor method to recognise Process end - then you are free to
exit your app.
As I can understood you used SWING for creating UI.
You can set
yourFrame.setDefaultCloseOperation(EXIT_ON_CLOSE);
for your frame. This must help.
I tried using Swing code in a JSP page. To my surprise it does work well and fine.
But I cannot judge if it is OK to use Swing with JSP?
Basically I want to display some pop up reports from Database. I was thinking to display a JFrame pop up/ applet to do the trick.
But do a web browser require any additional plugin for this?
Or is it fine to do such a thingy? Any guidance will be helpful.
Always remember that every java fragment you insert into your JSP is executed server-side, so it can be deceitful (it may seem to work in your development local machine, but it is only because the server and the client side are running on the same box).
The proper way to do this would be to write an Applet and include it into your page - this way, the browser will download it to client side and run it there. You should subclass JApplet (http://docs.oracle.com/javase/8/docs/api/javax/swing/JApplet.html) and then you will be able to use Swing components at will
The library works but your controls will never be shown at the client side (browser) but at the server (if it is that you have a working window service: Ms Windows, X11, Xorg,...).
I don't think that is a good practice and I would only use Swing library classes not to show GUI components but to use some classes to store special objects such as ImageIcon to store icons. But never to try to paint them.
I have a project where I use JLaTeXMath to generate a PNG within a JSP representing some math equations, in this context, I use javax.swing.JLabel to generate the image:
TeXFormula formula = new TeXFormula(texCode);
TeXIcon texImg = formula.createTeXIcon(TeXConstants.STYLE_DISPLAY, 25);
BufferedImage img = new BufferedImage(texImg.getIconWidth(), texImg.getIconHeight(),
BufferedImage.TYPE_4BYTE_ABGR);
texImg.paintIcon(new JLabel(),img.getGraphics(), 0, 0);
try {
OutputStream os = res.getOutputStream();
res.setContentType("image/png");
ImageIO.write(img, "png", os);
os.close();
res.flushBuffer();
} catch (Exception ex) {
log.warn("LaTeX renderer: " + ex.toString() + "\t" + "Msg: " + ex.getMessage());
return;
}
the JSP would run on the server,and probably display the GUI there,
but why would you want that? In the meantime, the person at the client
who submitted the request would be sitting there waiting for somebody
at the server end to close the Swing window so the JSP could get on
with its work.
So i would say that it is not feasible.
I have to create an application that will automatically open a powerpoint file, let it play through, and then close it. Not only do I need to figure out HOW to close it, but I also must detect when it closes or stops.
First option:
I know how long each powerpoint will play for, so I can hardcode when to close the file. I just need to know how to do that. There are no methods in the desktop class (that I could find) for closing.
Second option:
If someone knows a microsoft powerpoint api that lets me open powerpoints and use java to progress through the slideshow and get the state or something, that'd be great. I wouldn't have to go into each presentation and count the number of slides and the transition timer on each slide.
The opening, letting it play, and closing it is a small part of the app I need to create. But here is what I have so far with regards to THIS problem:
File myfile = new File("PowerPoint.ppsx");
try {
Desktop.getDesktop().open(myfile);
} catch (IOException ex) {
Logger.getLogger(Sc.class.getName()).log(Level.SEVERE, null, ex);
}
Probably this is the solution how to close external program:
http://www.java-forums.org/new-java/59691-close-another-program.html#post285956
If you want to detect when program has stopped running then you can start new thread with loop which from time to time will check if the program process is still running, using the same method as mentioned in link.
This is solution only for one (Windows) platform, Java is not the best choice for such tasks.
Here a solution using JNA. First we get the handle, we search using the "class name" of the window. You can determine the class name for a specific program (in this case Powerpoint) with a special utility like Spy++ (included with Visual Studio). It's possible to make the search more precise using the class name and the window caption (but here I use only the class name) so if you have more than one presentation running ... you may not close the good one!.
import com.sun.jna.platform.win32.User32;
import com.sun.jna.platform.win32.WinUser;
import com.sun.jna.platform.win32.WinDef.HWND;
// https://github.com/twall/jna#readme
// you need 2 jars : jna-3.5.1.jar and platform-3.5.1.jar
public class KillMyPP {
public static void main(String[] args) {
HWND hwnd = User32.INSTANCE.FindWindow("screenClass", null);
if (hwnd == null) {
System.out.println("PPSX is not running");
}
else {
User32.INSTANCE.PostMessage(hwnd, WinUser.WM_QUIT, null, null);
}
}
}
I am developing the network application in which I want to run my J2ME MIDP application in background without any GUI so that is any way to construct the application is such manner.
try this
set your current Display to null. so there will not be any form or alert running on the screen. But however your code will be running in the background.
Display display = Display.getDisplay(this); // here 'this' points to Midlet
display.setCurrent(null);
it easy just have a code of line on any event for example in the click of button
Display.getDisplay (this).setCurrent (null);
and return back the control via
Display.getDisplay (this).setCurrent (mycanvas);
Yes this code works Good,
display = Display.getDisplay(this);
public void startApp()
{
display.setCurrent(form);
}
public void pauseApp()
{
}
public void hide()
{
Display.getDisplay (this).setCurrent (null);
}
This is will work like, make a button can after clicking it call hide Function, or you call this hide function in constructor so it will hide itself when app start, can you keep unHide statement in appStart() so if you Tab the program then it will unHide app again.
NOTE: you said you are working on Network app, but some mobile will turn off the Internet Connection, when the Mobile screen Turn Off. please check this. and If you found any solution It will be Good to share here.
I have been working with a Java applet which is an applet that helps to write using only a mouse. For my case, I am trying to incorporate this into my webiste project as follows:
When the user clicks on any input element (textbox/textarea) on the page, this JAVA applet loads on the webpage itself. In the screenshot of the JAVA applet seen below, the user points to an alphabet to and the corresponding text gets written in the text box of the applet.
Now what I am trying to do is to get this text from the TextBox of the applet to the input element on the webpage. I know that this needs an interaction between the Java and JavaScript, but not being a pro, I really do not have the catch. Here's the Java applet and the code I have written.
Java applet and jQuery code (298kB): http://bit.ly/jItN9m
Please could somebdoy help for extending this code.
Thanks a lot!
Update
I searched somewhere and found this -> To get the text inside of Java text box, a getter method in the Applet to retrieve the text:
public class MyApplet extends JApplet {
// ...
public String getTextBoxText() { return myTextBox.getText(); }
}
In the JQuery code, the following lines are to be added I think:
var textBoxText = $("#applet-id")[0].getTextBoxText();
//Now do something with the text
For the code of the applet, I saw a GNOME git page here. The getText call already exists -- look at the bottom of this file: http://git.gnome.org/browse/dasher/tree/java/dasher/applet/JDasherApplet.java
I'd need to call 'getCurrentEditBoxText' but when should this method 'getCurrentEditBoxText' be called?
In my case, I would probably have to do it when the user clicks in a new input control etc.
You can have full communication between your Applet and any javascript method on the page. Kyle has a good post demonstrating how the Javascript can call the applet and request the text value. However, I presume you want the HTML Textfield to update with each mouse click, meaning the applet needs to communicate with the page. I would modify your javascript to something like this:
var activeTextArea = null;
$('textarea, input').click(function() {
$(this).dasher();
activeTextArea = this;
});
function updateText(text) {
// Careful: I think textarea and input have different
// methods for setting the value. Check the
// jQuery documentation
$(activeTextArea).val(text);
}
Assuming you have the source for the applet, you can have it communicate with the above javascript function. Add this import:
import netscape.javascript.JSObject;
And then, in whatever onClick handler you have for the mouse clicks, add:
// After the Applet Text has been updated
JSObject win = null;
try {
win = (JSObject) JSObject.getWindow(Applet.this);
win.call("updateText", new Object[] { textBox.getText() });
} catch (Exception ex) {
// oops
}
That will update the text each time that chunk of code is called. If you do NOT have access to the applet source, things get trickier. You'd need to set some manner of javascript timeout that constantly reads the value from the applet, but this assumes the applet has such a method that returns the value of the textbox.
See Also: http://java.sun.com/products/plugin/1.3/docs/jsobject.html
Update Modifying the applet is your best shot since that is where any event would be triggered. For example, if you want the HTML TextField to change on every click, the click happens in the applet which would need to be modified to trigger the update, as described above. Without modifying the applet, I see two options. Option #1 uses a timer:
var timer;
var activeTextArea;
$('textarea, input').click(function() {
$(this).dasher();
activeTextArea = this;
updateText();
}
function updateText() {
// Same warnings about textarea vs. input
$(activeTextArea).val($('#appletId')[0].getCurrentEditBoxText());
timer = setTimeout("updateText()", 50);
}
function stopUpdating() {
clearTimeout(timer);
}
This is similar to the code above except clicking on a text area triggers the looping function updateText() which will set the value of the HTML text field to the value of the Applet text field every 50ms. This will potentially introduce a minor delay between click and update, but it'll be small. You can increase the timer frequency, but that will add a performance drain. I don't see where you've 'hidden' the applet, but that same function should call stopUpdating so that we are no longer trying to contact a hidden applet.
Option #2 (not coded)
I would be to try and capture the click in the Applet as it bubbles through the HTML Dom. Then, you could skip the timer and put a click() behavior on the Applet container to do the same update. I'm not sure if such events bubble, though, so not sure if this would work. Even if it did, I'm not sure how compatible it would be across browsers.
Option #3
Third option is to not update the HTML text field on every click. This would simply be a combination of Kyle's and my posts above to set the value of the text field whenever you 'finish' with the applet.
Here's a possible solution. To get the text inside of your Java text box, write a getter method in the Applet to retrieve the text:
public class MyApplet extends JApplet {
// ...
public String getTextBoxText() { return myTextBox.getText(); }
}
In your JQuery code, add the following lines:
var textBoxText = $("#applet-id")[0].getTextBoxText();
//Now do something with the text
I found most of what I posted above here. Hope this helps.
This page explains how to manipulate DOM from a Java applet. To find the input element, simply call the document.getElementById(id) function with id of an id attribute of the text input box.