Copying From One File (source) To Another File (destination)
Jul 5, 2014
I have a file(source.txt) that contains some texts. Now, the java code is to run through each line in the source file and check if that line begins with a number and if true, copy that line to the destination file(destination.txt). I have the code but I am not sure why I can't loop through each line in the source.txt file. Below is my java code:
public static void copyFile(File source, File destination) {
BufferedReader br;
try {
FileWriter fw = new FileWriter(destination.getAbsoluteFile());
PrintWriter bw = new PrintWriter(fw);
br = new BufferedReader(new FileReader(source));
String line = new String();
[Code] ....
As shown in the source.txt file, there are 4 lines in the file but when the execution gets to while ((line = br.readLine()) != null) , it executes to false.. Why this is so?
below is the source.txt file
12 is a number
Green is bad
5 is not so cool
you are right
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May 14, 2015
I'm currently new to java and I would just like to ask if Socket is sufficient for this file transfer app I'm planning to work on.
The specs are as follows:
~ Move/Copy Files of selected folder/s to a single folder(consolidating them) within the same machine and Network
~ File type will be specified on GUI and those specified will be the ones transferred
~ option to choose Move or Copy of files
~ ability to create/select folder of transfer destination
Here is an draft of what the GUI will look like.
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Aug 1, 2014
Is there a way I can package a file INTO a jar file from a directory, not the other way around?
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Jun 13, 2014
This is a snippet code that im developing. (no source of it) . I am facing a trouble to extract file in the same directory as the source file (example: extract here option)
public class HelperAction {
public static void unzip(String zipFilePath)throws IOException {
File dir = new File(zipFilePath.substring(0,zipFilePath.length()));
// create output directory if it doesn't exist
if(!dir.exists()) dir.mkdirs();
FileInputStream fis;
[Code] ....
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Dec 27, 2014
[code=java]
public static void main(String[] args) throws FileNotFoundException, IOException {
// TODO code application logic here
FileReader fr = new FileReader("gautam.txt");
BufferedReader br = new BufferedReader(fr);
[Code] ....
Whats wrong with this code?
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Jun 10, 2014
Java Code: import jxl.read.biff.BiffException;
import java.io.*;
import java.util.*;
import jxl.*;
import jxl.write.*;
public class MainProgram{
public static void main(String[]args){
try{
Workbook workbook = Workbook.getWorkbook(new File("myfile.xls"));
[Code]...
Not sure why this code isnt working for me, it makes an empty excel file called output, but never copies the contents in "myfile" to that output file. I have Excel 2010 but I saved both of them as 97-2003 workbooks. Am I missing something? Do you have to go cell by cell to copy an excel file with JXL?
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May 21, 2014
I am developing a web application in java(JSF 2.0 - Prime Faces). I need to do below operation. My appllication is running on WLS server. WLS is deployed on a server(say Machine-X). In my application i have a requirement , where i have to copy file from Machine-X to another Machine-Y. The Machine-Y is access restricted.
When i tried to copy the file from my app, getting no access exception. I have full control over Machine-Y. We cannot use SFTP as SFTP cannot be installed on target machine(Machine-Y). Robocopy is failing for some use cases. Is there any other way we can copy/write file from one server to other by providing userid/password in java
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Aug 30, 2014
Have the following .bat file that compiles the ReadMindWave.java source with jna and jfreechart. I get a javac error saying 'no source' when the .bat is run, as the .java source needs to be included in the .bat file. Where it goes in the following .bat file?
@echo off
echo Compiling %1 with JNA and JFreeChart...
javac -Xlint:deprecation -cp "C:jna-master*;C:jfreechart-1.0.19libjfreechart-1.0.19.jar;C:jfreechart-1.0.19libjcommon-1.0.23.jar;."%*
The file to compile is in C:MindWaveTestsReadMindWave.java
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Jun 8, 2014
how to add an error message when my program can't find the file the user inputs.
For example:
Enter your source code:
D:Data StructsProjectssrcHelloWorld (I didn't put .java on purpose)
Exception in thread "main" java.io.FileNotFoundException: D:Data StructsProjectsAssignment 3srcHelloWorld (The system cannot find the path specified)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(Unknown Source)
at java.io.FileInputStream.<init>(Unknown Source)
at java.io.FileReader.<init>(Unknown Source)
at HomeworkDriverFour.main(HomeworkDriverFour.java:14)
//Can I get rid of the exception above and replace it with "File not found!"
Enter your source code:This is what I have so far:
import java.io.*;
import java.util.*;
public class HomeworkDriverFour {
public static void main(String[] args) throws IOException {
// TODO Auto-generated method stub
[code]...
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Jan 22, 2015
when i try to compile following source file, there is a error which states "MovieTestDrive is public, so must be declared in a file MovieTestDrive.java" i didnot understand. i am beginner in java;
class Movie
{
String title;
String genre;
int rating;
void playit()
{
System.out.println("playing the movie");
}
}
public class MovieTestDrive
[code]....
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Mar 30, 2014
To be specific, how can I use enumeration of one source-code file in another.
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Oct 9, 2014
"If you define a public class or an interface in your class, then it should match the name of the java source code file."
Does the statement above mean the following should compile fine ?
public class Animal{
public class Animal{ }
}
The author gives an example saying that if you have a class Multiple.java and in that class, you have:
public class Multiple{}, then it should compile.
But this does not compile. I tried it.
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Nov 3, 2014
I am having hard time to grasp the concept of java as i am beginner. according to different sources found in internet, only one class is written in one source file. and all those class can be accessed through the main class.
my question is
1.can we access one class present in one source file, through another class present in another source file [not through the class containing main method]?
2.can we create more than 1 class in same source file?is there special way to do it? i do get error always when i try to do so
3.can multiple classes contain main method? or should there be only single class containing it?
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Nov 6, 2014
My goals:
1) Have some source file be read in
2) Specify what arithmetic operators to swap (+, -, /, *)
2) If an arithmetic operator is read (like a + sign etc) then we swap it with its opposite (- for example)
3) Once the swap is complete, the rest of the file stays the same even if more operators are in the file...it is then output to a file (I am going with 1mutation.java)
4) This is where it gets tricky....it then picks up where it left off to finish reading the + operators (or whatever was specified) and repeats steps 2-3 (but the operator that is already swapped gets left as it was / skipped) and the output is saved as 2mutation.java.
The most I have been able to manage is having it changed 1 operator or all of them at once. I deleted a lot of my work to start fresh / master one operator for the time being. Here is what I have:
import java.io.BufferedInputStream;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
public class OperatorSub {
[Code] ....
This is the data file I am using. (see attached) The file should be .java or .cpp but I stuck with .txt for now. How to tackle this? Am I on the right track?
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Jan 25, 2014
My problem is that I want to load an Image from the source directory in Canavas' paint() method.
My code is currently (in a try/catch)
g.drawImage(ImageIO.read(new File(imageLocation)), imageX, imageY, null);
Where imageLocation leads to an image on my HDD ("C:UsersVladdeDocumentsFolders-Filesfolder.png")
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Feb 10, 2015
how java imports libraries from a jar file inside a source. Let's say I have the following code on Something.java file,
import com.mycomanyA.*;
import com.mycomanyB.*;
public class Something{
public static void main(String ... args){
// code goes here...
}
}
And the Something.java is inside the following structure...
A.jar
com/
mycompanyA/
A.class
Another.class
B.jar
com/
mycompanyB/
B.class
neededImage.gif
bin-folder/
org/
apache/
Something.java
To compile this code(Something.java) from command line I want to use the following command,
javac org/apache/Something.class
And for the compilation to be successful, I'll have to be just above bin-folder because...
- > Only then my default class path will be (.) and java would automatically include A.jar and B.jar(the other way is to add the jar files using -cp argument, which I want to avoid in this scenario)
- > And for the import org.mycompanyX to work I'll have to be in the (.) directory.
Are my assumptions correct about how java find jar contents imported in a source file?
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Oct 20, 2014
I have a question about the following snippet concerning the steps the javac compiler follows to compile a program:
[...]at first, searching a class within a package is discussed if the latter doesn't contain a full package name[...]
It is a compile-time error if more than one class is found. (Classes must be unique, so the order of the import statements doesn't matter.)
The compiler goes one step further. It looks at the source files to see if the source is newer than the class file. If so, the source file is recompiled automatically. Recall that you can import only public classes from other packages. A source file can only contain one public class, and the names of the file and the public class must match. Therefore, the compiler can easily locate source files for public classes.
However, you can import nonpublic classes from the current package. These classes may be defined in source files with different names. If you import a class from the current package, the compiler searches all source files of the current package to see which one defines the class. I don't quite understand the red fragment. I wondered if the word "import" nonpublic classes from the current package weren't a synonym for the word "use", since why would we want to import a class from the same package when compiler searches the current package automatically anyway?
However I wanted to test nonpublic classes that are contained in source file which name doesn't match the class name:
NonpublicClass.java:
Java Code:
package com.work.company;
class NonpublicClass
{
public void description() {
System.out.println("Working!");
}
} mh_sh_highlight_all('java');
[Code] ....
Everything's fine when the source file names are the same as above. However, when I change NonpublicClass.java to a different name, there's an error "cannot find symbol" in:
Java Code: NonpublicClass v = new NonpublicClass(); mh_sh_highlight_all('java');
I noticed that the class file for NonpublicClass isn't even generated so that's probably the cause. If I change to the directory of the package the NonpublicClass is contained in and compile it directly, i.e. issue for example:
Java Code: javac NonpublicClass_different_name.java mh_sh_highlight_all('java');
Then a proper class file is generated with the class name, that is NonpublicClass.class, and afterwards I can compile the main program in Start.java.
So the question is what am I missing regarding the cited quote that reads:
If you import a class from the current package, the compiler searches all source files of the current package to see which one defines the class.
? Because adding such an import to CompanyClass.java:
import com.work.company.NonpublicClass;
didn't work either...
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Feb 3, 2014
Why is this not valid in java:
Both uses public with the same class/interface name.
Test.java:
public class Test implements Test{
/// Some codes
}
public interface Test {
///Some methods
}
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Oct 31, 2014
I am trying to complete this question. I understand the most of it but I haven't go a clue to read in the file name.
Full question: Implement a program that reads in a Java source code file and checks to see if it has balanced {}brackets. Your program should use a stack, implemented as a linked list, to check the brackets.
NOTE: you can use a reference called top which points to the head of the list. Your program should run as a command line program and should take a filename as an argument and print one of BALANCED or NOT BALANCED.
For example: c:> java checkBalanced "myProgram.java" BALANCED
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Jun 7, 2014
This is my class with the GUI:
import java.awt.FlowLayout;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import javax.swing.JFrame;
import javax.swing.JTextField;
import javax.swing.JPasswordField;
[code]....
Eclipse error message:
Exception in thread "main" java.lang.NullPointerException
at javax.swing.ImageIcon.<init>(ImageIcon.java:205)
at GUI.<init>(GUI.java:26)
at Apples.main(Apples.java:7)
i think the problem is to do with my images not being recognised. I put them in my source in User>...>workspace>src which is correct as far as i know. From what i know the images should show up if i look at my src file in eclipse but they dont. I tried changing the file type from .png to .jpg but it makes no difference.
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Apr 23, 2015
I am trying to remove a line based on user input. myFile.txt looks like:
Matt
Brian
John
However when I enter "Brian" (to remove this line), It is deleted on the temp file (myTempFile.txt), but not renamed back to the original file (myFile).
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;
[code]....
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Sep 7, 2014
Here's the code and i keep getting this error
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import Desktop.java stuff.freetts-122-bin .zip.freetts-1.2 .javadoc.com.sun.speech.freetts.Voice;;
import Desktop.java stuff.freetts-122-bin .zip.freetts-1.2 .javadoc.com.sun.speech.freetts.VoiceManager;;
[Code] ....
Here it exists
Attached image(s)
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Oct 26, 2014
I am doing a pretty basic program with a fixed origin city and five destination cities. I am having trouble with entering passenger details. This is what I tried, but then I cannot retain all passenger details to print later on in the final ticket.
System.out.println("Enter flight details of child passengers (below 12 years)");
System.out.println("Enter Name");
for(a = 1; a <= cp; ++a)
{
//cp is number of child passengers, a is loop variable
String name = br.readLine();
System.out.println("1. " + name);
}
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Apr 22, 2014
I am creating a web application that runs on server X(unix) and it has another unix system mounted on it. I want to generate the file tree structure of this mounted unix file system and show it on to a web application so that users can select a file and move it onto this current unix machine.
I know this sounds stupid and you may want to say why cant we directly copy the file, I am doing a proof of concept and using this as a basis.
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Dec 8, 2014
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data.
Here is the base Product class that must be used to create the objects for the array.
public class Product
{
public String pName;
public String stringName;
public double price;
public int quanity;
[Code] .....
And then here is the data from the text file that i must extract to use to create product objects.
Dill Seed,938,34
Mustard Seed,100,64
Coriander Powder,924,18
Turmeric,836,80
Cinnamon (Ground Korintje),951,10
Cinnamon (Ground) Xtra Hi Oil (2x),614,31
Cinnamon (Ground) High Oil (1X),682,19
These continue for about 40-50 entries, they are not separated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name separated with spaces, then price after a comma, then quantity after the second comma.....
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Dec 9, 2014
I am working on a project that requires me to build a database with random access file, representing products, the base product contains a name (about 30 characters), a price (double), and a quantity (integer). I have worked on this project for probably 15+ hours and have tried so many things and feel like I've barley made any progress...
The part i am really struggling with is taking the data from the text file and creating an object array with it using the product class. Once ive accomplished that, i have to use that data to create a random access file with the data. Here is the base Product class that must be used to create the objects for the array.
public class Product
{
public String pName;
public String stringName;
public double price;
public int quanity;
[Code]...
these continue for about 40-50 entries, they are not seperated by a blank line though i had to add those so it would display correctly, each entry is on its own line with name seperated with spaces, then price after a comma, then quanity after the second comma.....
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