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java.io.FileNotFoundException: Joiners.txt (Access Denied)

Here is my problem. The path is true and the error is access denied.
I tried other solution but none of them work for me.
//this is my arraylist which i give value from the txt
ArrayList<Person> PersonArrayList = new ArrayList<Person>();
FileReader inFile = new
FileReader("C:\\Users\\canertasan\\Desktop");
//this is my path but access denied is problem?
BufferedReader inStream = new BufferedReader(inFile);
String InstaNameText;
while ((InstaNameText = inStream.readLine()) != null) {
PersonData.add(new Person(InstaNameText));
inStream.close();
}

The pathname refers to a folder not a file, and you cannot open a folder as a Reader.
The solution depends on what you are trying to do.
If you are trying to read the names of the files in the folder, then use File.list() -> String[] and iterate the array.
If you are trying to read the content of all of the files in the folder, then use File.listFiles() -> File[] and iterate the array. For each file, open, read lines and then close the file.
If you are trying to read the content of a specific file in the Desktop folder, then use the pathname for the file, not the folder.

Desktop isn't a file, it's a folder
FileReader should be given a file name as parameter
String filename = "C:\\Users\\UserName\\Desktop\\Joiners.txt"; //Fullpath txt file
String currentLine; //Current line
FileReader fr = null;
BufferedReader br = null;
try {
fr = new FileReader(filename);
br = new BufferedReader(fr);
while((currentLine = br.readLine()) != null){
System.out.println(currentLine);
}
}
catch(FileNotFoundException ex){
ex.printStackTrace();
}
catch(IOException ex){
ex.printStackTrace();
}
try {
if (br != null)
br.close();
if (fr != null)
fr.close();
}
catch (IOException ex) {
ex.printStackTrace();
}

How to check if a file exists in java

Im having a problem in checking if a file exists in Java. However the IF block seems to work , but the ELSE seems dont. see, when a file exist, it will prompt a box that says, 'File found.' which happens in my program whenever a file do exist, the problem is errors flood in my console when a file dont exist. Can somebody tell me what's the easier and shorter way of coding my problem? thanks ! here's my code
public void actionPerformed(ActionEvent e) {
BufferedReader br = null;
File f = new File(textField.getText());
String path = new String("C:\\Users\\theBeard\\workspace\\LeapYear\\");
try {
String sCurrentLine;
br = new BufferedReader(new FileReader(path+f));
if (f.exists())
{
JOptionPane.showMessageDialog(null, textField.getText()+" found" );
while ((sCurrentLine = br.readLine()) != null) {
textArea.append(sCurrentLine);
textArea.append(System.lineSeparator());
}
}
else
{
JOptionPane.showMessageDialog(null, textField.getText()+" not found" );
}
} catch (IOException ex) {
ex.printStackTrace();
} finally {
try {
if (br != null)
{
br.close();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
});

The problem is with this line:
br = new BufferedReader(new FileReader(path+f));
You're appending a File to a String, which doesn't make sense. You should append a String to a String, in this case textField.getText()) appended to path.
This line will throw an exception if the file doesn't exist as per the documentation of FileReader:
Throws:
FileNotFoundException - if the named file does not exist, is a directory rather than a regular file, or for some other reason cannot be opened for reading.
This causes your program to reach the catch clause and print an exception stack trace. You should only call this line when f.exists() returns true:
if (f.exists())
{
br = new BufferedReader(new FileReader(path + textField.getText()));
...
}

Look at these lines of your code:
br = new BufferedReader(new FileReader(path+f));
if (f.exists())
You are trying to open the file before checking whether it exists. So if the attempt to open it fails with a FileNotFoundException, the test is never reached.

String path = "C:\\Path\\To\File\\Directory\\";
String fileName = "NameOfFile.ext";
File f = new File(path, fileName);
if(f.exists()) {
//<code for file existing>
} else {
//<code for file not existing>
}

You have to instantiate the BufferedReader after checking the existence of the file.
String path = new String("C:\\Users\\theBeard\\workspace\\LeapYear\\");
File f = new File(path + textField.getText());
...
if (f.exists())
{
br = new BufferedReader(new FileReader(f.getAbsolutePath())); // or br = new BufferedReader(f);
...

Reading .txt files in java

Reading a file in Java. I get the "FileNotFound" exception.
Exception:
java.io.FileNotFoundException: something.txt (The file was not found)
at java.io.FileInputStream.open(Native Method)
at java.io.FileInputStream.<init>(Unknown Source)
at java.io.FileReader.<init>(Unknown Source)
at rmihello.ReadStringFromFileLineByLine.main(ReadStringFromFileLineByLine.java:13)
Even though my file is in my bin right next to my sourcecode:
I have also tried giving it the entire path to my file, e.g.
path = "C:/Users/Alexander/Desktop/java/something.txt"
or
path = "cd 'C:/Users/Alexander/Desktop/java/something.txt'"
All of it fails
Here's my code
import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
public class ReadStringFromFileLineByLine {
public static void main(String[] args) {
try {
String path = "something.txt";
File file = new File(path);
FileReader fileReader = new FileReader(file);
BufferedReader bufferedReader = new BufferedReader(fileReader);
StringBuffer stringBuffer = new StringBuffer();
String line;
while ((line = bufferedReader.readLine()) != null) {
stringBuffer.append(line);
stringBuffer.append("\n");
}
fileReader.close();
System.out.println("Contents of file:");
System.out.println(stringBuffer.toString());
} catch (IOException e) {
e.printStackTrace();
}
}
}

A relative path adds to uncertainty where a file-not-found stems from.
As you tried alternatives, handle the error:
File file = new File("C:/.../something.txt");
try {
...
} catch (FileNotFoundException e) {
File full = file.getAbsoluteFile();
File dir = file.getParentFile();
while (dir != null && !dir.exists()) {
dir = dir.getParentFile();
}
System.out.printf("File %s does not exist under %s%n",
full.getPath(),
dir == null ? "/" : dir.getPath());
} catch (IOException e2) {
}
Tips:
StringBuilder is faster, successor of StringBuffer.
New style (since Java 7):
Path path = Paths.get("C:/...");
byte[] content = Files.readAllBytes(path);
String contentText = new String(content); // Default encoding

As mentioned in comments, your code should start like this:
Path file = ; //Specify the path to your file
Take a look at Reading, Writing, and Creating Files in Java for more information
Edit:
Just edit your code like this it works fine for me:
public static void main(String[] args){
String path = "C://Something.txt"; // I put the file under the C: path in my example
try {
File file = new File(path);
FileReader fileReader = new FileReader(file);
BufferedReader bufferedReader = new BufferedReader(fileReader);
StringBuffer stringBuffer = new StringBuffer();
String line;
while ((line = bufferedReader.readLine()) != null) {
stringBuffer.append(line);
stringBuffer.append("\n");
}
fileReader.close();
System.out.println("Contents of file:");
System.out.println(stringBuffer.toString());
} catch (IOException e) {
e.printStackTrace();
}
}
Then just change the path to fit yours.

if you insert your text files into a folder named text_files for example, then you can access it using
File f = new File("text_files/something.txt");

Saving String Input on Android

Right, I've been trying to find a solution to this for a good while, but it's just not working for some reason.
In short, what I want to do is save every input String the user inputs into a file. Every time the activity is created again, I want to re-input these strings into a new instance of an object.
This code is what I use to create the file and read info from it, used in the onCreate() method of activity
try {
String brain = "brain";
File file = new File(this.getFilesDir(), brain);
if (!file.exists()) {
file.createNewFile();
}
BufferedReader in = new BufferedReader(new FileReader(file));
String s; // This feeds the object MegaAndroid with the strings, sequentially
while ((s = in.readLine()) != null) {
MegaAndroid.add(s);
}
in.close();
} catch (IOException e) {
e.printStackTrace();
}
After that, every time the user inputs some text, the strings are saved onto the file:
try {
String brain = "brain";
File file = new File(this.getFilesDir(), brain);
if (!file.exists()) {
file.createNewFile();
}
BufferedWriter out = new BufferedWriter(new FileWriter(file));
out.write(message); // message is a string that holds the user input
out.close();
} catch (IOException e) {
e.printStackTrace();
}
For some reason, however, every time the application is killed, the data is lost.
What am I doing wrong?
EDIT: Also, if I were to access this file from another class, how can I?

As we discussed in the commend section the chief problem with the code is that your execution of FileWriter occurred prior to your FileReader operation while truncating the file. For you to maintain the file contents you want to set the write operation to an append:
BufferedWriter out = new BufferedWriter(new FileWriter(file,true));
out.write(message);
out.newLine();
out.close();
However, if every entry on the EditText is received then shipped into the file you'll just be writing data byte after byte beside it. It is easy to get contents similar to
This is line #1This is line #2
Instead of the desired
This is line #1
This is line #2
which would be corrected by having the BufferedWriter pass a newline after each write to the file.

This is what I do for file reading.
try{
File sdCard = Environment.getExternalStorageDirectory();
File dir = new File (sdCard.getAbsolutePath() + "/whereyouwantfile");
dir.mkdirs();
Log.d(TAG,"path: "+dir.getAbsolutePath());
File file = new File(dir, "VERSION_FILENAME");
FileInputStream f = new FileInputStream(file);
//FileInputStream fis = context.openFileInput(VERSION_FILENAME);
BufferedReader reader = new BufferedReader(new InputStreamReader(f));
String line = reader.readLine();
Log.d(TAG,"first line versions: "+line);
while(line != null){
Log.d(TAG,"line: "+line);
//Process line how you need
line = reader.readLine();
}
reader.close();
f.close();
}
catch(Exception e){
Log.e(TAG,"Error retrieving cached data.");
}
And the following for writing
try{
File sdCard = Environment.getExternalStorageDirectory();
File dir = new File (sdCard.getAbsolutePath() + "/whereyouwantfile");
dir.mkdirs();
File file = new File(dir, "CONTENT_FILENAME");
FileOutputStream f = new FileOutputStream(file);
//FileOutputStream fos = context.openFileOutput(CONTENT_FILENAME, Context.MODE_PRIVATE);
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(f));
Set<String> keys = Content.keySet();
for(String key : keys){
String data = Content.get(key);
Log.d(TAG,"Writing: "+key+","+data);
writer.write(data);
writer.newLine();
}
writer.close();
f.close();
}
catch(Exception e){
e.printStackTrace();
Log.e(TAG,"Error writing cached data.");
}
You can use the private mode if you don't want the rest of the world to be able to see your files, but it is often useful to see them when debugging.

Test if file exists

I'm trying to open a file in android like this :
try
{
FileInputStream fIn = context.openFileInput(FILE);
DataInputStream in = new DataInputStream(fIn);
BufferedReader br = new BufferedReader(new InputStreamReader(in));
if(in!=null)
in.close();
}
catch(Exception e)
{ }
, but in case the file does not exists a file not found exception is thrown . I'd like to know how could I test if the file exists before attempting to open it.

I think the best way to know if a file exists, without actually trying to open it, is as follows:
File file = getContext().getFileStreamPath(FILE_NAME);
if(file.exists()) ...

The documentation says Context.openFileInput either returns an inputStream (file found) or throws a FileNotFoundException (not found)
http://developer.android.com/reference/android/content/Context.html#openFileInput(java.lang.String)
So it looks like the exception is your "test".
You could also try using standard
java.io.File file = new java.io.File(PATHTOYOURCONTEXT , FILE);
if (file.exists()) {
FileInputStream fIn = new FileInputStream(file);
}
But that is not recommended. Context.openFileInput() and Context.openFileOutput() make sure you stay in your applications storage context on the device, and that all of your files get
deleted when your app gets uninstalled.

With the standard java.io.File this is the function I have created, and works correctly:
private static final String APP_SD_PATH = "/Android/data/com.pkg.myPackage";
...
public boolean fileExistsInSD(String sFileName){
String sFolder = Environment.getExternalStorageDirectory().toString() +
APP_SD_PATH + "/Myfolder";
String sFile=sFolder+"/"+sFileName;
java.io.File file = new java.io.File(sFile);
return file.exists();
}

why dont you just catch the FileNotFound exception and take that as the file not being present.

If you want to ensure a file exists (i.e. if it doesn't exist create a new one, if it does then don't erase it) then use File.createNewFile:
https://docs.oracle.com/javase/7/docs/api/java/io/File.html#createNewFile()
e.g.
{
String pathName = <file path name>
File file = new File (pathName);
Uri pathURI = Uri.fromFile (file);
boolean created;
String mIOException = "";
String mSecException = "";
try
{
created = file.createNewFile();
if (created)
{
ctxt.sendBroadcast (new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE, pathURI));
}
}
catch (IOException ioex)
{
mIOException = ioex.getMessage();
}
catch (SecurityException sex)
{
mSecException = sex.getMessage();
}
}

If you want to open a file in any case (i.e. if it doesn't exist create a new one, if it does append to the old one) you can use this, no testing necessary:
public static void write_custom_log(String message){
File root = Environment.getExternalStorageDirectory();
try{
BufferedWriter fw = new BufferedWriter(new FileWriter(new File("/mnt/sdcard/tjb_tests/tjb_log_file.txt"),true));
if (root.canWrite()){
fw.write(message);
fw.close();
}
} catch (IOException e) {
Log.e("One", "Could not write file " + e.getMessage());
}
}

My suggestion is to check length of the file. if file.length() returns 0 that means file doesn't exist.