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Writing to file in Documents folder in internal storage

I've been trying to save text to a file in the documents folder in internal storage to be accessed by file manager so i can read it, I've tried several methods including using a writer, but I can't seem to get it to work, I'm not trying to save to external storage, I don't have external storage, only internal, and that's where my documents folder is, so I'm assuming I don't have to bother with the permissions in manifest, I threw in the setReadable just in case but I still can't find it in the documents folder, this is where I'm currently at.
public void writeToFile(String string){
try {
File file = new File(Environment.DIRECTORY_DOCUMENTS, "myFile.txt");
file.setReadable(true);
FileOutputStream stream = new FileOutputStream(file);
stream.write(string.getBytes(string));
stream.flush();
stream.close();
}
catch (IOException e) {
e.printStackTrace();
}
}

File file = new File(Environment.DIRECTORY_DOCUMENTS, "myFile.txt");
File file = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOCUMENTS), "myFile.txt");

Convert string and byte[] to file in JAVA

I have an interface with this strings and bytes array
public interface EmailAttachment {
String getFileName();
String getFileVersion();
byte[] getContent();
String getType();
}
i want to put all of this in a file, in my class Service how could i called?:
#Override
public Boolean sendEmail(EmailAttachment attachment) {
File file = new File( "HERE,I want to bring everything");
uploadFile(file);
}
If i use attachment.getFileName(),attachment.getFileVersion(),attachment.getContent(),attachment.getType()
it brings me an error because the file needs a path

try this out create a File object with the file name and pass it on to FileOutputStream.
OutputStream accepts byte array to store it in file, once uploading done close the stream.
String FILENAME = "";
File file = new File(FILENAME);
OutputStream os = new FileOutputStream(file);
// here you can write bytes to file using FileOutputStream
os.write(bytes);
// Close the file
os.close();

BufferedWriter is not writing text to text file

I have a BufferedWriter which is being used to write to a file which has just been created in the given directory, however, for some reason it is not writing the text that it reads from another file, here is my code:
private static final String tempFileDir = System.getProperty("user.dir") + "/TempATM.txt";
File tempFile = new File(tempFileDir); //Create temporary file to write new info to
File toRenameTo = new File("VirtualATM.txt"); //filename to rename temp file to
if (!tempFile.exists() && !tempFile.isDirectory()) {
tempFile.createNewFile(); //Create temp file if it doesn't already exist.
}
FileOutputStream fos = new FileOutputStream(tempFile, true); //For writing new balance
Writer bw = new BufferedWriter(new OutputStreamWriter(fos, "UTF8"));//For writing new balance
String newLineRead = null;
FileReader fileReader = new FileReader("VirtualATM.txt");//for reading from file
BufferedReader newBufferedReader = new BufferedReader(fileReader);//for reading from file
while((newLineRead = newBufferedReader.readLine()) != null){
if(!newLineRead.contains(cardNumberStr)){
bw.append(newLineRead); //If the line does not contain user entered card number, write line to new file.
((BufferedWriter) bw).newLine();
}else if(newLineRead.contains(cardNumberStr)){
bw.append(newAccountDetails); //Write updated account details if the line read contains users account number
((BufferedWriter) bw).newLine();
}
}
File toDeleteFile = new File("dirToWriteFile"); //File path to delete the file.
if(!toDeleteFile.delete()){
JOptionPane.showMessageDialog(null, "FATAL ERROR! Could not delete VirtualATM.txt", "Error", JOptionPane.ERROR_MESSAGE); // for if there is an error when deleting file
}
if(!file.renameTo(toRenameTo)){
JOptionPane.showMessageDialog(null, "FATAL ERROR! Could not rename the file to VirtualATM.txt", "Error", JOptionPane.ERROR_MESSAGE);//for if there is an error renaming file
}
Edit:
I am also having trouble deleting and renaming the text file, could any suggest what may be causing this problem, what SecurityExceptions etc. may be preventing Java from deleting and renaming a text file (.txt) on Windows 8.1?

You need to either flush the buffer post writing the data to buffer like
bw.flush();
or close the writer like
bw.close();//handle exception if you are not using AutoCloseable feature.

You must either flush the buffer to the disk after writing the data using:
bw.flush();
or / and if you have finished writing the data, you must always close the writer which will automatically flush the data to the disk before closing using:
bw.close();
Hope this helps. Good luck and have fun programming!
Cheers,
Lofty

Filehandling file path

Basically i have two questions. i am using the below code to read and write z text file.
File myFile = new File("/sdcard/mysdfile.txt");
myFile.createNewFile();
FileOutputStream fOut = new FileOutputStream(myFile);
OutputStreamWriter myOutWriter =
new OutputStreamWriter(fOut);
myOutWriter.append("my text here");
myOutWriter.close();
this create a new file every time i want this to OPEN_OR_CREATE(if file already exist don't create a new one)
Ad my second question is that how to change the path "/sdcard/mysdfile.txt" i want this file to stored in my sdcard -> subFolder1 -> SubFolder2
Thnaks

Do not use hardcoded /sdcard or /mnt/sdcard or your app will fail as devices vary on location or mountpoint of that storage. To get the right location use
Environment.getExternalStorageDirectory();
See docs here.
To append content to existing file use new FileOutputStream(myFile, true); instead of just new FileOutputStream(myFile); - see docs on that constructor here.
As for
how to change the path "/sdcard/mysdfile.txt"
Aside from getting rid of /sdcard as said above, just add subfolders to the paths: MyFolder1/MyFolder2/mysdfile.txt. Note these folder have to exists or the path will be invalid. You can always create it by calling myFile.mkdirs().

Replace
FileOutputStream fOut = new FileOutputStream(myFile);
with
FileOutputStream fOut = new FileOutputStream(myFile, true); //true means append mode.
Appart from that I have one suggestion for you.
Never never hardcode /sdcard in code,Rather consider writing.
File myFile = new File(Environment.getExternalStorageDirectory(),"mysdfile.txt");

Try my solution to write to end of text file
private void writeFile (String str){
try {
File f = new File(Environment.getExternalStorageDirectory().toString(),"tasklist.txt");
FileWriter fw = new FileWriter(f, true);
fw.write(str+"\n");
fw.flush();
fw.close();
} catch (Exception e) {
}
}
*File(Environment.getExternalStorageDirectory().toString()+"your/pth/here","tasklist.txt");

File dir = Environment.getExternalStorageDirectory();
File f = new File(dir+"/subFolder1/",xyz.txt); <-- HOW TO USE SUB FOLDER
if(file.exists())
{
// code to APPEND
}
else
{
// code to write new one
}

1> OPEN_OR_CREATE
You can try or can replace MODE_APPEND with true like #Vipul's suggestion
FileOutputStream fOut = openFileOutput(your_path_file, MODE_APPEND);
//it means if the file is exist the content you want write will append into it.
2> stored in my sdcard -> subFolder1 -> SubFolder2
you can use Environment.getExternalStorageDirectory().getAbsolutePath() to get full file path the SDCard. Then concat strings to get the file path you want. Ex:
String baseDir = Environment.getExternalStorageDirectory().getAbsolutePath();
String fileName = "myFile.txt";
File f = new File(baseDir + File.separator + subfolder1 + File.separator + subfoler2, fileName);

In Java 7 we can do it this way:
Path path = Paths.get("/sdcard/mysdfile.txt");
BufferedWriter wrt = Files.newBufferedWriter(path, StandardCharsets.UTF_8, StandardOpenOption.APPEND);

Java FileWriter overwrite

I have a piece of code that generates new data whenever there is new data available as InputStream . The same file is overwritten everytime. Sometimes the file becomes 0 kb before it gets written. A webservice reads these files at regular intervals. I need to avoid the case when the file is 0 bytes.
How do it do this? Will locks help in this case? If the browser comes in to read a file which is locked, will the browser continue to show old data from the cache until the lock is released and file is available to be read again.
try{
String outputFile = "output.html";
FileWriter fWriter = new FileWriter(outputFile);
//write the data ...
fWriter .flush();
outputFile = "anotheroutput.html";
fWriter = new FileWriter(outputFile);
//write the data ...
fWriter .flush();
fWriter.close();
}
catch(Exception e)
{
e.prinStackTrace();
}

Try writing to a temporary file (in the same file system) and once the file write is complete move it into place using File.renameTo(). If you underlying file system supports atomic move operations (most do) then you should get the behaviour that you require. If you are running on windows you will have to make sure you close the file after reading otherwise the file move will fail.
public class Data
{
private final File file;
protected Data(String fileName) {
this.file = new File(filename);
}
/* above is in some class somehwere
* then your code brings new info to the file
*/
//
public synchronized accessFile(String data) {
try {
// Create temporary file
String tempFilename = UUID.randomUUID().toString() + ".tmp";
File tempFile = new File(tempFilename);
//write the data ...
FileWriter fWriter = new FileWriter(tempFile);
fWriter.write(data);
fWriter.flush();
fWriter.close();
// Move the new file in place
if (!tempFile.renameTo(file)) {
// You may want to retry if move fails?
throw new IOException("Move Failed");
}
} catch(Exception e) {
// Do something sensible with the exception.
e.prinStackTrace();
}
}
}

FileWriter fWriter = new FileWriter(fileName,true);
try using above :-)

Your requirement is not very clear. Do you want to write a new name file every time or you want to append to the same file or you want to over write the same file? Anyway all three cases are easy and from the API you can manage it.
If the issue is that a web service is reading the file which is not yet complete i.e. is in writing phase. In your web service you should check if the file is read only, then only you read the file. In writing phase once writing is finished set the file to read only.
The 0Kb file happens because you are overwriting the same file again. Overwriting cleans up all the data and then start writing the new content.

public class Data
{
String fileName;
protected Data(String fileName)
{
this.fileName= fileName;
return; // return from constructor often not needed.
}
/* above is in some class somehwere
* then your code brings new info to the file
*/
//
public synchronized accessFile(String data)
{
try
{
// File name to be class member.
FileWriter fWriter = new FileWriter(fileName);
//write the data ...
fWriter.write(data);
fWriter .flush();
fWriter .close();
return;
}
catch(Exception e)
{
e.prinStackTrace();
}
this is not needed:
outputFile = "anotheroutput.html";
fWriter = new FileWriter(outputFile);
//write the data ...
fWriter .flush();
fWriter.close();
that's because work on the file is a method of class Data