When I enter the full file path (C:\Users\djustinwebb\Documents\BlueJ Projects\LightHouse) for "search" and it attempts to open the file I get the error:
java.io.FileNotFoundException: C:\Users\djustinwebb\Documents\BlueJ Projects\LightHouse (Access is denied) (in java.io.FileInputStream)
I have input "invoicedata.txt" for search and it worked even though it doesn't read through the file properly but I would like to know why it won't work when I use the full file path. What do I need to do to use the full file path without running into this error?
public String searchCase()throws FileNotFoundException
{
String fileLine = null;
StringTokenizer stok = null;
Scanner inputFile = new Scanner(new File(search));
String whatever = null;
while(inputFile.hasNextLine())
{
fileLine = inputFile.nextLine();
stok = new StringTokenizer(fileLine,",");
caseLCount++;
while(stok.hasMoreTokens())
{
if(userWord.equals(stok.nextToken()))
{
caseWCount++;
whatever += caseLCount + ".\n";
}//end if
}// end nested while
}//end outer while
inputFile.close();
return whatever;
}// end searchCase()
This happens because you are trying to open and read a directory, which is LightHouse here. You are supposed to enter the file name in the file path as well, like this, ..\LightHouse\invoicedata.txt.
If you want to distinguish between files and folders, use the isFile() and isDirectory() methods. You can get the contents of folders using the list() and listFiles() methods.
Related
I'm trying to create a new text file in java by having the user input their desired file name. However, when I look in the directory for the file after I run the code once, it doesn't show up.
import java.util.Scanner;
import java.io.File;
public class TestFile {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.print("Enter the desired name of your file: ");
String fileName = input.nextLine();
fileName = fileName + ".txt";
File file = new File(fileName);
}
}
Although, when I don't have the user input a file name and just have the code written with the name in quotation marks, the file ends up being created when I look back in the directory.
File file = new File("TestFile.txt")
Why won't it create a file when I try to use the String input from the user?
You must be mistaken because just calling new File(String) won't create a file. It will just create an instance of File class.
You need to call file.createNewFile().
Adding this at the end creates the file:-
if (file.createNewFile()) {
System.out.println("File created.");
} else {
System.out.println("File already exists.");
}
The following code worked for me:
Scanner input = new Scanner(System.in);
System.out.print("Enter the desired name of your file: ");
String fileName = input.nextLine();
fileName = fileName + ".txt";
File file = new File(fileName);
boolean isFileCreated = file.createNewFile(); // New change
System.out.print("Was the file created? -- ");
System.out.println(isFileCreated);
The only change made to your code is to call createNewFile method. This worked fine in all cases. Hope this helps.
From the API:
Atomically creates a new, empty file named by this abstract pathname
if and only if a file with this name does not yet exist. The check for
the existence of the file and the creation of the file if it does not
exist are a single operation that is atomic with respect to all other
filesystem activities that might affect the file. Note: this method
should not be used for file-locking, as the resulting protocol cannot
be made to work reliably. The FileLock facility should be used
instead.
Please use below code to solve your issue. You just have to call createNewFile() method it will create file in your project location. You can also provide the location where you want to create file otherwise it will create file at your project location to create file at specified location you have to provide location of your system like below
String fileLocation="fileLocation"+fileName;
File file = new File(fileLocation);
import java.util.Scanner;
import java.io.File;
public class TestFile {
public static void main(String[] args) throws IOException {
Scanner input = new Scanner(System.in);
System.out.print("Enter the desired name of your file: ");
String fileName = input.nextLine();
fileName = fileName + ".txt";
File file = new File(fileName);
file.createNewFile();
}
}
When faced with issues like this, it's really, really, really important to go hit the JavaDocs, because 90% of the time, it's just a misunderstanding of how the APIs work.
File is described as:
An abstract representation of file and directory pathnames.
This means that creating an instance of File does not create a file nor does the file have to exist, it's just away of describing a virtual concept of a file.
Further reading of the docs would have lead you to File#createNewFile which is described as doing:
Atomically creates a new, empty file named by this abstract pathname if and only if a file with this name does not yet exist. The check for the existence of the file and the creation of the file if it does not exist are a single operation that is atomic with respect to all other filesystem activities that might affect the file.
When you initialize your File file = new File("TestFile.txt"), it is not created yet.
You should write something to your file using FileWriter or others.
File f = new File(fileName);
FileWriter w = new FileWriter(f);
w.write("aaa");
w.flush();
or using f.createNewFile() as suggested in other answer.
Then you can see your file and its content.
It has been a long time since I messed with files. I am trying to take a txt file I make in eclipse and use it in this code. The code to handle getting file name, finding file, and scanning it is:
System.out.println("Input from a file");
System.out.print("Enter file name: ");
String str = expression.nextLine();
int i = 0;
File file = new File(str);
Scanner fScan = new Scanner(file);
All I get are FileNotFoundExceptions. My file is in the same exact folder that all my classes for this program are in. I can't find an actual helpful answer online either .
So if someone could point out where I am going wrong that would be great :)
all of these lines of code you are having should be inside a try{} and outside have a catch, that would catch the fileNotFoundException, for example,
Try{
/*your code here*/
// but try this
Scanner scannerName = new Scanner("FileName.<extension>"); //extension being .txt, etc
String str;
while(scannerName.hasNext());{
str = scannerName.nextLine();
/*work with str here*/
}
Catch(FileNotFoundException e){
System.out.println("File not found");
}
Are you sure that the file is in the root folder ? The default working directory, is the project directory.
If you are sure that your file is there then it's either your mistaken when typing the name of your file, or somethine else is happening, to figure it out, I suggest you to try the following 3 tests :
1-make sure when you type the name of the file there is no mistake
2-Try to put the full path of the file and see if now it will find it
3-Try to put as name something like
new File("src/pa/Yourinput.txt").
If you have the file in the same package where is the class file then you can try this one also:
Scanner fScan = new Scanner(this.getClass().getResourceAsStream("abc.txt"));
//do not forget to close the Scanner in the end
fScan.close()
OR
Looking a file abc.txt from resources folder
File file = new File("resources/abc.txt");
Here is the project structure
My goal is to write a Java program in Netbeans to copy a directory and all of its contents, including subdirectories and their contents. To do so, I first ask the user for source directory and destination where it will be copied. From here, my program should make a new directory in the new location with same name as the source directory. Then my program should create an array with File class objects for each item in the contents of the source directory. Next, I tried to iterate the array, and for each item - if it is a file, it should copy to the new directory- if it is a directory, it should recursively call this method to the copy the directory and all of its contents.
An extremely useful program if I could just get it to work correctly. It is difficult for me right now to understand the entire logic needed to make this program run efficiently.
When I run the program, it returns that the file cannot be found but this is just not true. So my code has to be wrong somewhere. Any help would be greatly appreciated guys.
Thank you.
package copydirectories;
/**
* CSCI 112, Ch. 18 Ex. 5
* #author zhughes3
* Last edited Tuesday, March 11th, 2014 # 9pm
*/
import java.io.*;
import java.util.Scanner;
public class CopyDirectories {
/**
* #param args the command line arguments
*/
public static void main(String[] args) throws Exception {
//Create a new instance of scanner to get user input
Scanner scanner = new Scanner (System.in);
//Ask user to input the directory to be copied
System.out.print("Input directory to be copied.");
//Save input as String
String dirName = scanner.nextLine();
//Ask user to input destination where direction will be copied
System.out.print("Input destination directory will be moved to.");
//Save input as String
String destName = scanner.nextLine();
//Run method to determine if it is a directory or file
isDirFile(dirName, destName);
}//end main
public static void isDirFile (String source, String dest) throws Exception{
//Create a File object for new directory in new location with same name
//as source directory
File dirFile = new File (dest + source);
//Make the new directory
dirFile.mkdir();
//Create an array of File class objects for each item in the source
//directory
File[] entries;
//If source directory exists
if (dirFile.exists()){
//If the source directory is a directory
if (dirFile.isDirectory()){
//Get the data and load the array
entries = dirFile.listFiles();
//Iterate the array using alternate for statement
for (File entry : entries){
if (entry.isFile()){
copyFile (entry.getAbsolutePath(), dest);
} //end if
else {
isDirFile (entry.getAbsolutePath(), dest);
} //end else if
}//end for
}//end if
}//end if
else {
System.out.println("File does not exist.");
} //end else
}
public static void copyFile (String source, String dest) throws Exception {
//declare Files
File sourceFile = null;
File destFile = null;
//declare stream variables
FileInputStream sourceStream = null;
FileOutputStream destStream = null;
//declare buffering variables
BufferedInputStream bufferedSource = null;
BufferedOutputStream bufferedDest = null;
try {
//Create File objects for source and destination files
sourceFile = new File (source);
destFile = new File (dest);
//Create file streams for the source and destination
sourceStream = new FileInputStream(sourceFile);
destStream = new FileOutputStream(destFile);
//Buffer the file streams with a buffer size of 8k
bufferedSource = new BufferedInputStream(sourceStream,8182);
bufferedDest = new BufferedOutputStream(destStream,8182);
//Use an integer to transfer data between files
int transfer;
//Alert user as to what is happening
System.out.println("Beginning file copy:");
System.out.println("\tCopying " + source);
System.out.println("\tTo " + dest);
//Read a byte while checking for End of File (EOF)
while ((transfer = bufferedSource.read()) !=-1){
//Write a byte
bufferedDest.write(transfer);
}//end while
}//end try
catch (IOException e){
e.printStackTrace();
System.out.println("An unexpected I/O error occurred.");
}//end catch
finally {
//close file streams
if (bufferedSource !=null)
bufferedSource.close();
if (bufferedDest !=null)
bufferedDest.close();
System.out.println("Your files have been copied correctly and "
+ "closed.");
}//end finally
}//end copyDir
}//end class
If you read through JavaDocs, you will see that mkdir...
Creates the directory named by this abstract pathname.
This is a little obscure, but basically, it will only create the last level of the directory. For example, if you have a path of C:\this\is\a\long\path, mkdir would only attempt to create the path directory at the end of C:\this\is\a\long, but if C:\this\is\a\long doesn't exist it will fail.
Instead, if you use mkdirs
Creates the directory named by this abstract pathname, including any
necessary but nonexistent parent directories. Note that if this
operation fails it may have succeeded in creating some of the
necessary parent directories.
I'd also be check the results of these methods, as they will indicate if the operation was successful or not
I think entries = dirFile.listFiles(); looks wrong, you should be listing the files from the source directory, not the destination...
I am trying to read 2 files after i read the files i want to get their contents and manipulate the contents of the two files then update a new file which is the output. The files are in the same folder as the program but the program always throws a FileNotFoundException.
Below is my code:-
import java.io.*;
import java.util.Scanner;
public class UpdateMaster {
public static void main(String[] args)
{
String master = "Customer.dat";
String trans = "Transactns.dat";
String newMaster = "Temp.txt";
Scanner inputStreamMaster = null;
Scanner inputStreamTrans = null;
PrintWriter inputStreamNewMaster = null;
try
{
inputStreamMaster = new Scanner(new File(master));
inputStreamTrans = new Scanner(new File(trans));
inputStreamNewMaster = new PrintWriter(newMaster);
}
catch(FileNotFoundException e)
{
System.out.println("Error: you opend a file that does not exist.");
System.exit(0);
}
catch(IOException e)
{
System.out.println("Error.");
System.exit(0);
}
do
{
String transLine = inputStreamTrans.nextLine();
String masterLine = inputStreamMaster.nextLine();
String[] transLineArr = transLine.split(",");
String[] masterLineArr = masterLine.split(",");
int trAccNo = Integer.parseInt(transLineArr[0]);
int sales = Integer.parseInt(transLineArr[1]);
int masterAccNo = Integer.parseInt(masterLineArr[0]);
int balance = Integer.parseInt(masterLineArr[1]);
while(masterAccNo== trAccNo){
inputStreamNewMaster.println(trAccNo+ " , "+masterAccNo);
masterLine = inputStreamMaster.nextLine();
masterLineArr = masterLine.split(",");
masterAccNo = Integer.parseInt(masterLineArr[0]);
balance = Integer.parseInt(masterLineArr[1]);
}
balance = balance + sales;
inputStreamNewMaster.println(masterAccNo+ " , "+balance);
}while(inputStreamTrans.hasNextLine());
inputStreamMaster.close();
inputStreamTrans.close();
inputStreamNewMaster.close();
//System.out.println(" the line were written to "+ newMaster);
}
}
Like #Ankit Rustagi said in the comments, you need the full path of the files if you want to keep the current implementation.
However, there is a solution where you only need the file names: use BufferedReader / BufferedWriter. See here an example on how to use these classes (in the example it uses the full path but it works without it too).
Use absolute path
String master = "C:/Data/Customer.dat";
String trans = "C:/Data/Transactns.dat";
String newMaster = "C:/Data/Temp.txt";
The code works for me, i guess you misspelled some filename(s) or your files are in the wrong folder. I created your files on the same level as the src or the project. Also this is the folder where the files are exspected.
There's nothing wrong with using relative paths like tihis. What's happening is that your program is looking for the files in the directory where you execute the program, which doesn't have to be the folder of the program. You can confirm this by logging the absolute path of the files before you try to read them. For example:
File masterFile = new File(master);
System.out.printf("Using master file '%s'%n", masterFile.getAbsolutePath());
inputStreamMaster = new Scanner(masterFile);
In general you should not hardcode file paths but allow the user to specify them in someway, for example using command line arguments, a configuration file with a well known path, or an interactive user interface.
There is a way to locate the program's class file but it's a little tricky because Java allows classes to be loaded from compressed archives that may be located in remote systems. It's better to solve this problem in some other manner.
Try this:
String current = new java.io.File( "." ).getCanonicalPath();
System.out.println("I look for files in:"+current);
To see what directory your program expects to find its input files. If it shows the correct directory, check spelling of filenames. Otherwise, you have a clue as to what's gone wrong.
This is my code to read a text file. When I run this code, the output keeps saying "File not found.", which is the message of FileNotFoundException. I'm not sure what is the problem in this code.
Apparently this is part of the java. For the whole java file, it requires the user to input something and will create a text file using the input as a name.
After that the user should enter the name of the text file created before again (assume the user enters correctly) and then the program should read the text file.
I have done other parts of my program correctly, but the problem is when i enter the name again, it just can not find the text file, eventhough they are in the same folder.
public static ArrayList<DogShop> readFile()
{
try
{ // The name of the file which we will read from
String filename = "a.txt";
// Prepare to read from the file, using a Scanner object
File file = new File(filename);
Scanner in = new Scanner(file);
ArrayList<DogShop> shops = new ArrayList<DogShop>();
// Read each line until end of file is reached
while (in.hasNextLine())
{
// Read an entire line, which contains all the details for 1 account
String line = in.nextLine();
// Make a Scanner object to break up this line into parts
Scanner lineBreaker = new Scanner(line);
// 1st part is the account number
try
{ int shopNumber = lineBreaker.nextInt();
// 2nd part is the full name of the owner of the account
String owner = lineBreaker.next();
// 3rd part is the amount of money, but this includes the dollar sign
String equityWithDollarSign = lineBreaker.next();
int total = lineBreaker.nextInt();
// Get rid of the dollar sign;
// we use the subtring method from the String class (see the Java API),
// which returns a new string with the first 'n' characters chopped off,
// where 'n' is the parameter that you give it
String equityWithoutDollarSign = equityWithDollarSign.substring(1);
// Convert this balance into a double, we need this because the deposit method
// in the Account class needs a double, not a String
double equity = Double.parseDouble(equityWithoutDollarSign);
// Create an Account belonging to the owner we found in the file
DogShop s = new DogShop(owner);
// Put money into the account according to the amount of money we found in the file
s.getMoney(equity);
s.getDogs(total);
// Put the Account into the ArrayList
shops.add(s);
}
catch (InputMismatchException e)
{
System.out.println("File not found1.");
}
catch (NoSuchElementException e)
{
System.out.println("File not found2");
}
}
}
catch (FileNotFoundException e)
{
System.out.println("File not found");
} // Make an ArrayList to store all the accounts we will make
// Return the ArrayList containing all the accounts we made
return shops;
}
If you are working in some IDE like Eclipse or NetBeans, you should have that a.txt file in the root directory of your project. (and not in the folder where your .class files are built or anywhere else)
If not, you should specify the absolute path to that file.
Edit:
You would put the .txt file in the same place with the .class(usually also the .java file because you compile in the same folder) compiled files if you compile it by hand with javac. This is because it uses the relative path and the path tells the JVM the path where the executable file is located.
If you use some IDE, it will generate the compiled files for you using a Makefile or something similar for Windows and will consider it's default file structure, so he knows that the relative path begins from the root folder of the project.
Well.. Apparently the file does not exist or cannot be found. Try using a full path. You're probably reading from the wrong directory when you don't specify the path, unless a.txt is in your current working directory.
I would recommend loading the file as Resource and converting the input stream into string. This would give you the flexibility to load the file anywhere relative to the classpath
If you give a Scanner object a String, it will read it in as data. That is, "a.txt" does not open up a file called "a.txt". It literally reads in the characters 'a', '.', 't' and so forth.
This is according to Core Java Volume I, section 3.7.3.
If I find a solution to reading the actual paths, I will return and update this answer. The solution this text offers is to use
Scanner in = new Scanner(Paths.get("myfile.txt"));
But I can't get this to work because Path isn't recognized as a variable by the compiler. Perhaps I'm missing an import statement.
This should help you..:
import java.io.*;
import static java.lang.System.*;
/**
* Write a description of class InRead here.
*
* #author (your name)
* #version (a version number or a date)
*/
public class InRead
{
public InRead(String Recipe)
{
find(Recipe);
}
public void find(String Name){
String newRecipe= Name+".txt";
try{
FileReader fr= new FileReader(newRecipe);
BufferedReader br= new BufferedReader(fr);
String str;
while ((str=br.readLine()) != null){
out.println(str + "\n");
}
br.close();
}catch (IOException e){
out.println("File Not Found!");
}
}
}
Just another thing... Instead of System.out.println("Error Message Here"), use System.err.println("Error Message Here"). This will allow you to distinguish the differences between errors and normal code functioning by displaying the errors(i.e. everything inside System.err.println()) in red.
NOTE: It also works when used with System.err.print("Error Message Here")