i've got this code that i cant get to work as i want it to. when its exported and i run it the file i wants gets created but when i open the file there is a single number like 999998000001
import java.io.IOException;
import java.io.PrintWriter;
public class mainHej {
public static void main(String arg[]){
[code]...
How do i flush off the leading 0s from my results? I want to start with 1.
import java.util.Scanner;
public class Hex2Bin {
public static void main(String[] args) {
String hexStr;
int hexStrLen;
[code]....
i want to know when i have to use Flush in java , i saw alot of code that used it IO streaming , but i cannt understand how can i use it , or when i have to use it
View Replies View RelatedYou are given a file containing the names and addresses of company employees from many years ago that your manager has asked you to import into a database. You can use a CSV file and your database application to load the file, but the file your manager gave you was exported from an old, non-standard accounting system. Here is its format:
Fred|Flintstone
1212|Bedrock
Austin|Texas
Harry|Potter
1234|Hogwarts Road
[Code] .....
I'm tyring to print the same output in console to a text file, but I can only get the last line of the console output in the text file, not sure what is wrong with my code:
while (in.hasNextLine()) {
PrintWriter writer = new PrintWriter("output5.txt");
tempS = in.nextLine().toLowerCase();
System.out.println(wp.bestPages(tempS));
[code]....
What's causing only the last time to be printed in text file? Are there better ways to print console outputs into a text file than PrintWriter?
I've written a simple html/servlet program that has a user enter their name and password on a form and then either register or login using a submit button. I have the program working, except when a user doesn't fill in either of the text fields I can't figure out how to get it to print to the page. Right now I just have it printing to my Eclipse console which is not what I want. What am I missing?
HTML code:
<?xml version="1.0" encoding="ISO-8859-1" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>Cookies</title>
[code]....
If I am using the File object to read a file and PrintWriter object to write to a separate file, can I use them under one method. Or is the File one method and the PrintWriter another method?
View Replies View RelatedI thought you can use PrintWriter to write to the console but when I run the following code I only get "abc" printed to the console.
import java.io.*;
class Class1{
public static void main(String...abc) throws Exception{
PrintWriter writer = new PrintWriter(System.out);
writer.println("test");
System.out.println("abc");
}
}
How to write a new file:
import acm.program.*;
import java.io.*;
import java.io.PrintWriter.*;
import acm.util.*;
import javax.swing.*;
public class PrintWriter extends ConsoleProgram {
public void run() {
try {
PrintWriter wr = new PrintWriter( new FileWriter ("hello.txt") ) ;
wr.println("Hello world!");
wr.close();
} catch (IOException er) {
println("File could not be saved.");
}
}
}
(I added the imports at top myself.) However, I am getting compiler errors for the lines: PrintWriter wr = new PrintWriter( new FileWriter ("hello.txt") ) , which says that the constructor PrintWriter( FileWriter ) is undefined, and
wr.close();, which says close() method is undefined.
Pretty sure the only real problem is that PrintWriter is not accepting the FileWriter as constructor, but I don't see why. I have tried this on machine with JRE 1.4 and it worked as expected, creating new file titled "hello.txt", prints line of "Hello world!" in that file, and saves it to the directory I picked in the dialog. But I can't get it to work on this machine that uses Compiler 1.6, Java Runtime v8u25.
I have also tried using just a string in the parameter for PrintWriter, such as PrintWriter wr = new PrintWriter ("hello.txt") , and from what I can tell by reading the java spec for java 8, this should work. [URL] .... But I get error message for that constructor as well.
I am creating a car simulator that simulators the odometer and fuel gauge on a car. I want to print the results to a text file but it seems to be printing only the last two lines instead of all of them. How can I make it so it doesn't overwrite the previous input?
Here's my main method:
public static void main(String[] args) throws FileNotFoundException {
CarInstrumentSimulator carInstrumentSimulator = new CarInstrumentSimulator();
FuelGauge gas = carInstrumentSimulator.new FuelGauge();
[Code].....
I have done lots of PrintWriting before but this is the first time I have done it on my new computer and I'm having an error I haven't seen before. This is my code:
Rprint(){
try {
PrintWriter pout = new PrintWriter(new FileWriter("C:UsersJackDocumentsexample.r "));
pout.println("nums = c(1,2,5,6,8,10)");
pout.println("nums");
pout.close();
} catch (IOException ex) {
System.out.println("Error!");
Logger.getLogger(Rprint.class.getName()).log(Level .SEVERE, null, ex);
}
}
*** java.io.FileNotFoundException: C:UsersJackDocuments
This.txt (The filename, directory name or volume label syntax is incorrect) ***
I have a feeling it may be to do with permissions, because it lets me print simply ("example.r") into my project folder.
Write a program that asks the user for the names of two files. The first file should be opened for reading and the second file should be opened for writing. Ihe program should read the contents of the first file, change all characters to uppercase, and store the results in the second file. The second file will be a copy of the first file, except that all the characters w ill be uppercase. Use Notepad or another text editor to create a simple file that can be used to test the program
Here is my code. I Also made two text document files that are located in the same directory as the .class file (the code file) that are named OriginalFile and UpperCase respectively. Please let me know what I need to do. Here is the code.
import java.util.Scanner;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
public class UpperCaseFile
{
public static void main (String [] args) throws IOException
{
[Code]...
private static void getTablas(int num) {
//ciclos anidados
System.out.print("x");
//linea horizontal
for (int i = 1; i <= num; i++) {
System.out.printf("%3d ",i);
[Code] .....
For every stream that we create for java i/o we write at the end in finally block
finally
{
if(is!=null)
{
is.close();
}
}
It works
my question is as per syntax in if (is!=null) this means that if is means stream contain some value then close it(!=null)
then how it in my opnion it should be like (in logical way)
if stream contain nothing then close it
if(is==null)
{
is.close();
}
I am confuse about working this line
Following is the code on the click of a button, id like to know how do i close the current jframe on which the jButton4 is currently placed. I know how to send it to the next Jframe i.e JobCard. But need to close the current one. I tried using this.setVisible(true); But it does not work.
private void jButton4ActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.setVisible(false);
JobCard jobCard = new JobCard();
jobCard.setVisible(true);
}
how the entire application could be close when you click on X in a JDialog Box. I have tried
System.Exit (0)
but it only close the Dialog box
I didn't know about right method for correct close operation for JFrame component or kill the object. I found out few, which of them you are using usually???
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(false);
JFrame.DO_NOTHING_ON_CLOSE.
System.exit(0);
How to make a Jframe close without closing the whole operation, I started off using exit on close and changed it to hide on close and i also tried dispose on close for some reason it wont work. Here is what I have.
import java.awt.*;
import javax.swing.*;
public class GUILauncheralt{
public static void main(String[] args){
RetrieveWindow gui = new RetrieveWindow();
gui.setDefaultCloseOperation(JFrame.HIDE_ON_CLOSE);
gui.setSize(400, 200);
[Code] .....
I am writing a console application that is to make use of the system editor on *NIX. For that I have written a method which writes a string to a file, launches an editor to change that file, and then reads the file again. The problem is the call to run the editor doesn't wait for that application to have closed.
Java Code: Runtime.getRuntime().exec(editorcmd + " " + tmpfn); mh_sh_highlight_all('java'); I need the program to wait for the editor to have finished.
Does printwriter always truncates the existing file to 0 size before adding any new data ??
View Replies View RelatedI have a practice exercise here wherein I will add a JOptionPane to a program. When the close button is clicked, the JOptionPane will appear asking the user to exit the program. If the user clicks "Yes," it'll, of course, close the entire program and not just the JOptionPane, but if the user clicks "No," it will return to the program. Please refer to my code below:
try
{
output = new DataOutputStream(new FileOutputStream("ProjSixExe4.dat"));
}
catch(IOException ex) {
this.dispatchEvent(new WindowEvent(this, WindowEvent.WINDOW_CLOSING))
}
final JOptionPane optionpane = new JOptionPane("Are you sure you want to quit
this program?", JOptionPane.QUESTION_MESSAGE, JOptionPane.YES_NO_OPTION);
this.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
The exercise said it must be placed before the EXIT_ON_CLOSE portion.
I have JFrame and when I click a button which is in frame JDialog is opened. Now,how can I refresh JFrame when close JDoalog?
View Replies View RelatedI am making a simple battleship program, you have the menu and click Start to get the board with the bombs (4 buttons as of now) Each button has either a bomb or a defualtbutton. I created my button so it can't be unselected. The problem is I have the button in a Class.java and I want that to close in a period of time. What do you recommend using?
/*
* To change this license header, choose License Headers in Project Properties.
* To change this template file, choose Tools | Templates
* and open the template in the editor.
*/
package battleship;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.GridBagLayout;
[code]....
I can call the clas in my main jFrame but I want to close the class after a certain time.
I made UpdateInmateDisplayer a Singleton so that I could access it from the private class ButtonHandler. It works to display the first inmate's number on the screen but when I close out the window and click the Book Inmate button in CurInmatesDisplayer again, it only shows a blank window. I've tried adding the components again from the ButtonHandler in CurInmatesDisplayer but it doesn't work.
View Replies View RelatedI have added a windowListener to my JFrame but for some reason it is not being called when I click X to close the window. I need to send a message to a server to notify it that the client window is closed. Some code snippets below (some lines excluded for brevity):
public class ChatGUI extends javax.swing.JFrame {
....
setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE); // I have all the window constants here but has no effect other than closing the window without calling the listener...
addWindowListener(new java.awt.event.WindowAdapter() {
public void windowClosed(java.awt.event.WindowEvent evt) {
formWindowClosed(evt);
}
});
....
private void formWindowClosed(java.awt.event.WindowEvent evt) {
[code]....
This is resolved, needed to use...
addWindowListener(new java.awt.event.WindowAdapter() {
public void windowClosing(java.awt.event.WindowEvent evt) {
formWindowClosing(evt);
}
});
... instead.
I have a filechooser that works how it should and if anyone enters anything with a dot that isnt .xml it shows an invalid file name message. However when I dont choose a file and press cancel it still says that because when my boolean hits false it's the first thing it hits in that section of code.
if(!writeSuccess)
{
//display output messages in JOptionPane
JOptionPane.showMessageDialog(null,"Error, file name invalid", "Error", JOptionPane.ERROR_MESSAGE);
} else {
JOptionPane.showMessageDialog(null,"Export successful", "Success", JOptionPane.INFORMATION_MESSAGE);
//close the form
me.dispose();
}
If I want it to just close down without it saying anything is there sort of if statement I could do that would prevent this? But if it is an invalid file name it will still show that message?