Hi....
is there any way to clear screen in java such as the one in C languange..System("cls");??????Do I need to import any class ???
thanks...

 

 

*************************************************************
char esc = 27;
String clear = esc + "[2J";
System.out.print(clear);

And this line must be inside the config.sys:
device=c:\windows\command\ansi.sys
*************************************************************

Hi, I've already posted a question similar to yours few days ago. Luckily, I found a code that can clear off the console DOS screen in Window. However, I have big trouble in understanding the mechanism behind the code and desperately need some advice from all experts in this forum. Here is all the questions:

1) Why do I need this token "[2J"? What is it used for?
2) Why must I load the driver "ANSI.SYS" in order to have the program to work properly?
3) What is the mechanism that drives the program to clear off the DOS screen?

 

 

thanks for that...

 

 

<escape> + "[2J" is the ANSI escape sequence for clearing the screen.

For windoze, ANSI escape sequences will not work properly unless the ANSI device driver is loaded.

 

 

I seems doesn't work on NT, what can I do??
have any other methods??
thx

 

 

Wow, as miss cleo would say, " That's simply amazin' ". I never knew that this even existed, sweetness, thankyou very much!

-Jason Thomas.

 

 

I tried, but the output is:

<--[2J<--[2J

Note: <-- is representing an arrow pointing towards left (only one character)

 

 

If I'm not mistaken, I do believe the ibm Ascii Character 27 is indeed a left arrow...and the MS ascii 27 is ESC

 

 

Okay, then what is the ESC character for IBM ASCII?

 

 

You usually don't write command line applications in Java. That's just for really basic stuff or if it must run via a telnet connection or so, for everything that counts as real application, make your own command line window. Here's a "dirty", but simple one class implementation (usually one would use anonymous classes, but I wanted to keep it simple), that opens an own command line window, prints out some text, clears the screen after a break and after another break quits gracefully.

Compile with
javac Test.java

Start with either:
java Test

or on Windows you can use:
javaw Test

So you can close your DOS box and application continues running.

// File Test.java
import java.awt.*;
import java.awt.event.*;
 
public class Test extends Frame implements WindowListener {
    
    private final TextArea TA = new TextArea
            ("", 25, 80, TextArea.SCROLLBARS_NONE);
    private final String NEWLINE = "" + '\n';
    
    public Test() {
        TA.setEditable(false);
        add(TA);
        setTitle("Test Application");
        setResizable(false);
        addWindowListener(this);
        pack();
        setVisible(true);
        // The last methods were inherited
        // because we extend java.awt.Frame
    }
    
    public void print(String s) {
        TA.append(s);
    }
    
    public void println(String s) {
        TA.append(s);
        TA.append(NEWLINE);
    }
    
    public void cls() {
        TA.setText("");
    }
    
    public void kill() {
        dispose();
    }
    
    
    // We must implement the following as we are
    // implementing WindowListener
    
    public void windowDeactivated(WindowEvent e) {}
    public void windowDeiconified(WindowEvent e) {}
    public void windowIconified(WindowEvent e) {}
    public void windowOpened(WindowEvent e) {}
    
    public void windowActivated(WindowEvent e) {}
    
    public void windowClosed(WindowEvent e) {
        System.exit(0);
    }
    
    public void windowClosing(WindowEvent e) {
        dispose();
    }
            
    
    public static void main(String[] args) {
        Test t = new Test();
        t.println("Hello World!");
        t.print("Same line ");
        t.println("Test");
        try {
            Thread.sleep(5000); // Wait 5 seconds
        } catch (InterruptedException e) {
            // Do nothing, not critical to
            // be interrupted
        }
        t.cls();
        try {
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            // Do nothing, not critical to
            // be interrupted
        }
        t.kill();        
    }
}

 

 

Hey... that's cool and it works!

Alrighty - i'm extremely new to Java, i'm taking an intro to Java course in high school.

how would one go about getting input from such a text area? I'm cool getting input from a regular console, just not this fancy new thingey.

 

 

Hey... that's cool and it works!

Alrighty - i'm extremely new to Java, i'm taking an intro to Java course in high school.

how would one go about getting input from such a text area? I'm cool getting input from a regular console, just not this fancy new thingey.

 

 

Java does not support esc codes by default, you can get packages to do this for you:
http://www.pitman.co.za/projects/charva/
http://www.nongnu.org/jcurzez/

Google and this forum have a lot more information on this subject, I recomend searching for ncurses.

 

 

cant you use dos command?
for Windows
Runtime.getRuntime().exec("command cls");
or
Runtime.getRuntime().exec("cmd cls");

 

 

No, all this does is open up a new window, clear it, and close that window. I'm talking about clearing the parent process.