Proper Way to exit JAVA application after flie write

Proper Way to exit JAVA application after flie write - java

**UPDATE---The issue was not the file writer not closing but incorrect termination of the Java application. I have updated the question.
I have the following classes launching a JAVAFX web view and exposing some java objects to the web view's html.
public class FileSystemBridge {
private void writeToFile(String[] fileContents){
if (content!=null){
String fileName ="pathToFile";
BufferedWriter fileWriter;
for (int i =0; i<fileContents.length(); i++ ){
String fileContent fileContents[i]);
try {
fileName = fileName+Integer.toString(i)+".txt";
fileName = fileName.replaceAll("\\s","");
System.out.println(fileName);
File f= new File(filesDir+"/"+fileName);
f.createNewFile();
fileWriter = new BufferedWriter(new FileWriter(f));
fileWriter.write("");
fileWriter.write(fileContent);
fileWriter.flush();
fileWriter.close();
} catch (IOException e) {
System.out.println("in the exception!");
e.printStackTrace();
}
}
}
else {
System.out.println("no content");
}
System.out.println("done writing, exit app now");
}
public void exit(){
System.out.println("EXITING!");
Platform.exit();
System.exit(0);
}
}
The above class also has additional member classes who serve as POJOS to expose the structure of files being read/written to the "front-end" html.
I pass an instance of FileSystemBridge to the web view by overriding the default Browser class constructor and adding the following code.
webEngine.getLoadWorker().stateProperty().addListener(
(ObservableValue<? extends State> ov, State oldState,
State newState) -> {
if (newState == State.SUCCEEDED) {
JSObject context= (JSObject) webEngine.executeScript("window");
context.setMember("fsBridge", new FileSystemBridge());
webEngine.executeScript("init('desktop')");//the hook into our app essentially
}
});
The webEngine.executeScrit("init) essentially performs some initialization on our front end. Then on the javascript executing on the webview on user interaction we invoke our FileSystemBridge write method with a callback to invoke the FileSystemBridge's exit method, which is essentially a call to Platform.exit().
On user click
App.handleWrite(contentToBeWritten, function(success){
if (success){
console.log("inside success!");
App.handleExit();
}
});
then our handleWrite javascript function
handleWrite: function(content, callback){
fsBridge.callWrite(content);
retVal = true;//more logic to this but simplified for demo
callBack(retVal);
}
Now in the FileSystemBridge.exit() method I have added System.exit(0), which succesfully terminates my java instance which was the original problem.However I would like to know if this is the correct approach to handling the exiting of a java app which uses a JAVAFX webview. Are there unforeseen consequences to using System.exit(0) in this manner?

Java applications that create a UI don't terminate until certain conditions are met. For a JavaFX application, make sure you are closing all Stage instances.

If you can't manpulate it into a finally block per the previous answer, how about a try-with-resources? Like so (you'll need to remove the previous declaration of fileWriter):
'
for (int i =0; i<fileContents.length(); i++ ){
String fileContent fileContents[i]);
try {
fileName = fileName+Integer.toString(i)+".txt";
fileName = fileName.replaceAll("\\s","");
System.out.println(fileName);
File f= new File(filesDir+"/"+fileName);
f.createNewFile();
try(BufferedWriter fileWriter = new BufferedWriter(new FileWriter(f));)
{
fileWriter.write("");
fileWriter.write(fileContent);
}
} catch (IOException e) {
System.out.println("in the exception!");
e.printStackTrace();
}
}
'

Try putting the close in a finally block like below and see if it makes any difference.
try {
} catch (Exception e) {
} finally {
fileWriter.close();
}

I did see some pitfalls, but no real problem, especially as you handle the exceptions. The length() is an indication that you simplified the code here.
Try it in the newer style Path/Files as it is more "atomic" - even more simple.
String fileName ="pathToFile";
fileName = fileName.replaceAll("[\\s/\\\\]", "");
for (int i = 0; i < fileContents.length; i++) {
Path path = Paths.get(fileName + i + ".txt";
byte[] bytes = ("\ufeff" + fileContents).getBytes("UTF-8");
//Or: byte[] bytes = fileContents.getBytes();
try {
Files.write(path, bytes);
} catch (IOException e) {
System.out.println("Could not write " + path.getFileName());
}
}
This version writes in UTF-8 with a starting BOM char. The BOM is ugly, but allows Windows to recognize UTF-8. That allows special characters.
Files.write can have extra parameters list StandardOpenOptions.REPLACE_EXISTING.

Related

Save to text file [duplicate]

In Java, I have text from a text field in a String variable called "text".
How can I save the contents of the "text" variable to a file?

If you're simply outputting text, rather than any binary data, the following will work:
PrintWriter out = new PrintWriter("filename.txt");
Then, write your String to it, just like you would to any output stream:
out.println(text);
You'll need exception handling, as ever. Be sure to call out.close() when you've finished writing.
If you are using Java 7 or later, you can use the "try-with-resources statement" which will automatically close your PrintStream when you are done with it (ie exit the block) like so:
try (PrintWriter out = new PrintWriter("filename.txt")) {
out.println(text);
}
You will still need to explicitly throw the java.io.FileNotFoundException as before.

Apache Commons IO contains some great methods for doing this, in particular FileUtils contains the following method:
static void writeStringToFile(File file, String data, Charset charset)
which allows you to write text to a file in one method call:
FileUtils.writeStringToFile(new File("test.txt"), "Hello File", Charset.forName("UTF-8"));
You might also want to consider specifying the encoding for the file as well.

In Java 7 you can do this:
String content = "Hello File!";
String path = "C:/a.txt";
Files.write( Paths.get(path), content.getBytes());
There is more info here:
http://www.drdobbs.com/jvm/java-se-7-new-file-io/231600403

Take a look at the Java File API
a quick example:
try (PrintStream out = new PrintStream(new FileOutputStream("filename.txt"))) {
out.print(text);
}

Just did something similar in my project. Use FileWriter will simplify part of your job. And here you can find nice tutorial.
BufferedWriter writer = null;
try
{
writer = new BufferedWriter( new FileWriter( yourfilename));
writer.write( yourstring);
}
catch ( IOException e)
{
}
finally
{
try
{
if ( writer != null)
writer.close( );
}
catch ( IOException e)
{
}
}

Use FileUtils.writeStringToFile() from Apache Commons IO. No need to reinvent this particular wheel.

In Java 11 the java.nio.file.Files class was extended by two new utility methods to write a string into a file. The first method (see JavaDoc here) uses the charset UTF-8 as default:
Files.writeString(Path.of("my", "path"), "My String");
And the second method (see JavaDoc here) allows to specify an individual charset:
Files.writeString(Path.of("my", "path"), "My String", StandardCharset.ISO_8859_1);
Both methods have an optional Varargs parameter for setting file handling options (see JavaDoc here). The following example would create a non-existing file or append the string to an existing one:
Files.writeString(Path.of("my", "path"), "String to append", StandardOpenOption.CREATE, StandardOpenOption.APPEND);

You can use the modify the code below to write your file from whatever class or function is handling the text. One wonders though why the world needs a new text editor...
import java.io.*;
public class Main {
public static void main(String[] args) {
try {
String str = "SomeMoreTextIsHere";
File newTextFile = new File("C:/thetextfile.txt");
FileWriter fw = new FileWriter(newTextFile);
fw.write(str);
fw.close();
} catch (IOException iox) {
//do stuff with exception
iox.printStackTrace();
}
}
}

I prefer to rely on libraries whenever possible for this sort of operation. This makes me less likely to accidentally omit an important step (like mistake wolfsnipes made above). Some libraries are suggested above, but my favorite for this kind of thing is Google Guava. Guava has a class called Files which works nicely for this task:
// This is where the file goes.
File destination = new File("file.txt");
// This line isn't needed, but is really useful
// if you're a beginner and don't know where your file is going to end up.
System.out.println(destination.getAbsolutePath());
try {
Files.write(text, destination, Charset.forName("UTF-8"));
} catch (IOException e) {
// Useful error handling here
}

Using Java 7:
public static void writeToFile(String text, String targetFilePath) throws IOException
{
Path targetPath = Paths.get(targetFilePath);
byte[] bytes = text.getBytes(StandardCharsets.UTF_8);
Files.write(targetPath, bytes, StandardOpenOption.CREATE);
}

In case if you need create text file based on one single string:
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
public class StringWriteSample {
public static void main(String[] args) {
String text = "This is text to be saved in file";
try {
Files.write(Paths.get("my-file.txt"), text.getBytes());
} catch (IOException e) {
e.printStackTrace();
}
}
}

Use Apache Commons IO api. Its simple
Use API as
FileUtils.writeStringToFile(new File("FileNameToWrite.txt"), "stringToWrite");
Maven Dependency
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>

Use this, it is very readable:
import java.nio.file.Files;
import java.nio.file.Paths;
Files.write(Paths.get(path), lines.getBytes(), StandardOpenOption.WRITE);

import java.io.*;
private void stringToFile( String text, String fileName )
{
try
{
File file = new File( fileName );
// if file doesnt exists, then create it
if ( ! file.exists( ) )
{
file.createNewFile( );
}
FileWriter fw = new FileWriter( file.getAbsoluteFile( ) );
BufferedWriter bw = new BufferedWriter( fw );
bw.write( text );
bw.close( );
//System.out.println("Done writing to " + fileName); //For testing
}
catch( IOException e )
{
System.out.println("Error: " + e);
e.printStackTrace( );
}
} //End method stringToFile
You can insert this method into your classes. If you are using this method in a class with a main method, change this class to static by adding the static key word. Either way you will need to import java.io.* to make it work otherwise File, FileWriter and BufferedWriter will not be recognized.

You could do this:
import java.io.*;
import java.util.*;
class WriteText
{
public static void main(String[] args)
{
try {
String text = "Your sample content to save in a text file.";
BufferedWriter out = new BufferedWriter(new FileWriter("sample.txt"));
out.write(text);
out.close();
}
catch (IOException e)
{
System.out.println("Exception ");
}
return ;
}
};

Using org.apache.commons.io.FileUtils:
FileUtils.writeStringToFile(new File("log.txt"), "my string", Charset.defaultCharset());

If you only care about pushing one block of text to file, this will overwrite it each time.
JFileChooser chooser = new JFileChooser();
int returnVal = chooser.showSaveDialog(this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
FileOutputStream stream = null;
PrintStream out = null;
try {
File file = chooser.getSelectedFile();
stream = new FileOutputStream(file);
String text = "Your String goes here";
out = new PrintStream(stream);
out.print(text); //This will overwrite existing contents
} catch (Exception ex) {
//do something
} finally {
try {
if(stream!=null) stream.close();
if(out!=null) out.close();
} catch (Exception ex) {
//do something
}
}
}
This example allows the user to select a file using a file chooser.

Basically the same answer as here, but easy to copy/paste, and it just works ;-)
import java.io.FileWriter;
public void saveToFile(String data, String filename) {
try (
FileWriter fw = new FileWriter(filename)) {
fw.write(data);
} catch (Exception e) {
throw new RuntimeException(e);
}
}

private static void generateFile(String stringToWrite, String outputFile) {
try {
FileWriter writer = new FileWriter(outputFile);
writer.append(stringToWrite);
writer.flush();
writer.close();
log.debug("New File is generated ==>"+outputFile);
} catch (Exception exp) {
log.error("Exception in generateFile ", exp);
}
}

It's better to close the writer/outputstream in a finally block, just in case something happen
finally{
if(writer != null){
try{
writer.flush();
writer.close();
}
catch(IOException ioe){
ioe.printStackTrace();
}
}
}

I think the best way is using Files.write(Path path, Iterable<? extends CharSequence> lines, OpenOption... options):
String text = "content";
Path path = Paths.get("path", "to", "file");
Files.write(path, Arrays.asList(text));
See javadoc:
Write lines of text to a file. Each line is a char sequence and is
written to the file in sequence with each line terminated by the
platform's line separator, as defined by the system property
line.separator. Characters are encoded into bytes using the specified
charset.
The options parameter specifies how the the file is created or opened.
If no options are present then this method works as if the CREATE,
TRUNCATE_EXISTING, and WRITE options are present. In other words, it
opens the file for writing, creating the file if it doesn't exist, or
initially truncating an existing regular-file to a size of 0. The
method ensures that the file is closed when all lines have been
written (or an I/O error or other runtime exception is thrown). If an
I/O error occurs then it may do so after the file has created or
truncated, or after some bytes have been written to the file.
Please note. I see people have already answered with Java's built-in Files.write, but what's special in my answer which nobody seems to mention is the overloaded version of the method which takes an Iterable of CharSequence (i.e. String), instead of a byte[] array, thus text.getBytes() is not required, which is a bit cleaner I think.

If you wish to keep the carriage return characters from the string into a file
here is an code example:
jLabel1 = new JLabel("Enter SQL Statements or SQL Commands:");
orderButton = new JButton("Execute");
textArea = new JTextArea();
...
// String captured from JTextArea()
orderButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
// When Execute button is pressed
String tempQuery = textArea.getText();
tempQuery = tempQuery.replaceAll("\n", "\r\n");
try (PrintStream out = new PrintStream(new FileOutputStream("C:/Temp/tempQuery.sql"))) {
out.print(tempQuery);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(tempQuery);
}
});

I have published a library that saves files, and handles everything with one line of code only, you can find it here along with its documentation
Github repository
and the answer to your question is so easy
String path = FileSaver
.get()
.save(string.getBytes(),"file.txt");

My way is based on stream due to running on all Android versions and needs of fecthing resources such as URL/URI, any suggestion is welcome.
As far as concerned, streams (InputStream and OutputStream) transfer binary data, when developer goes to write a string to a stream, must first convert it to bytes, or in other words encode it.
public boolean writeStringToFile(File file, String string, Charset charset) {
if (file == null) return false;
if (string == null) return false;
return writeBytesToFile(file, string.getBytes((charset == null) ? DEFAULT_CHARSET:charset));
}
public boolean writeBytesToFile(File file, byte[] data) {
if (file == null) return false;
if (data == null) return false;
FileOutputStream fos;
BufferedOutputStream bos;
try {
fos = new FileOutputStream(file);
bos = new BufferedOutputStream(fos);
bos.write(data, 0, data.length);
bos.flush();
bos.close();
fos.close();
} catch (IOException e) {
e.printStackTrace();
Logger.e("!!! IOException");
return false;
}
return true;
}

How to save a csv file in JFileChooser ?

Hi I am not able to save a csv file.I am not even getting error in the write command.I have used FileChooser. And can any one explain the use of Approve option as i am new to swing.
if(e.getActionCommand()=="SaveTweet")
{
JFileChooser savePlaylistDialog = new JFileChooser();
savePlaylistDialog.setSelectedFile(new File( ".csv"));
int status = savePlaylistDialog.showSaveDialog(savePlaylistDialog);
try {
if (status == JFileChooser.APPROVE_OPTION) {
File savePlaylist = savePlaylistDialog.getSelectedFile();
ICsvListWriter csvWriter = null;
try {
TwitterProject obj=new TwitterProject();
String [][] tweet=obj.generateBottweet(username,interval,Btweet,no);
csvWriter = new CsvListWriter(new FileWriter("savePlaylist"),
CsvPreference.STANDARD_PREFERENCE);
for (int i = 0; i < tweet.length; i++) {
csvWriter.write(tweet[i]);
}
} catch (IOException e1) {
e1.printStackTrace();
} finally {
try {
System.out.println("closing file");
csvWriter.close();
} catch (IOException e1) {
}
}
} else if (status == JFileChooser.CANCEL_OPTION) {
// User has pressed cancel button
}
} catch (Exception ex) {
JOptionPane.showMessageDialog(null, "File could not be written, try again.");
}
}
}

Two things jump out...
First, you comparing Object reference of String instead of contents...
if(e.getActionCommand()=="SaveTweet")
Will very rarely be true, as the Object references will most likely never be equal, instead, you should try using something like...
if("SaveTweet".equals(e.getActionCommand()))
Which will compare the contents of the two Strings, but will also guard against possible NullPointerExceptions...
Second, you are ignoring the File the the user selected, for example, you get a reference to the file the user selects using...
File savePlaylist = savePlaylistDialog.getSelectedFile();
But then you create a FileWriter which simply uses a String value...
csvWriter = new CsvListWriter(new FileWriter("savePlaylist"));
Instead, should try using something like...
csvWriter = new CsvListWriter(new FileWriter(savePlaylist));
Which will write the contents to the file that the user selects...
ps- I would also drop...
savePlaylistDialog.setSelectedFile(new File( ".csv"));
As it doesn't actually make sense, I doubt there would be file called .csv...or more to the point, it's highly unlikely...

To compare String objects in java use .equals() method instead of "==" operator
change
if(e.getActionCommand()=="SaveTweet")
to
if("SaveTweet".equals(e.getActionCommand()))
if you want to ignore the case use like below code
if("SaveTweet".equalsIgnoreCase(e.getActionCommand()))

Did you also test the writing method? Which implementation of csvwriter do you use? In some cases (com.csvwriter) you need to call flush() before close().

FFMPEG in Java issue

I have the following code in a java Web Service:
public boolean makeFile(String fileName, String audio)
{
if (makeUserFolder())
{
File file = new File(getUserFolderPath() + fileName + amr);
FileOutputStream fileOutputStream = null;
try
{
file.createNewFile();
fileOutputStream = new FileOutputStream(file);
fileOutputStream.write(Base64.decode(audio));
return true;
}
catch(FileNotFoundException ex)
{
return false;
}
catch(IOException ex)
{
return false;
}
finally{
try {
fileOutputStream.close();
convertFile(fileName);
} catch (IOException ex) {
Logger.getLogger(FileUtils.class.getName()).log(Level.SEVERE, null, ex);
}
}
}
else
return false;
}
public boolean convertFile(String fileName)
{
Process ffmpeg;
String filePath = this.userFolderPath + fileName;
try {
ProcessBuilder pb = new ProcessBuilder("ffmpeg","-i",filePath + amr,filePath + mp3);
pb.redirectErrorStream();
ffmpeg = pb.start();
} catch (IOException ex) {
return false;
}
return true;
}
It used to work and now it simply won't execute the ffmpeg conversion for some reason. I thought it was a problem with my file but after running the command from terminal no errors are thrown or anything, thought it was maybe permissions issue but all the permissions have been granted in the folder I'm saving the files. I noticed that the input BufferedReader ins being set to null after running the process, any idea what's happening?

First of all, a small nitpick with your code...when you create the FileOutputStream you create it using a string rather than a File, when you have already created the File before, so you might as well recycle that rather than force the FileOutputStream to instantiate the File itself.
Another small nitpick is the fact that when you are writing out the audio file, you should enclose that in a try block and close the output stream in a finally block. If you are allowed to add a new library to your project, you might use Guava which has a method Files.write(byte[],File), which will take care of all the dirty resource management for you.
The only thing that I can see that looks like a definite bug is the fact that you are ignoring the error stream of ffmpeg. If you are blocking waiting for input on the stdout of ffmpeg, then it will not work.
The easiest way to take care of this bug is to use ProcessBuilder instead of Runtime.
ProcessBuilder pb = new ProcessBuilder("ffmpeg","-i",filePath+amr,filePath+mp3);
pb.redirectErrorStream(); // This will make both stdout and stderr be redirected to process.getInputStream();
ffmpeg = pb.start();
If you start it this way, then your current code will be able to read both input streams fully. It is possible that the stderr was hiding some error that you were not able to see due to not reading it.
If that was not your problem, I would recommend using absolute paths with ffmpeg...in other words:
String lastdot = file.getName().lastIndexOf('.');
File mp3file = new File(file.getParentFile(),file.getName().substring(0,lastdot)+".mp3");
ProcessBuilder pb = new ProcessBuilder("ffmpeg","-i",file.getAbsolutePath(),mp3file.getAbsolutePath());
// ...
If that doesn't work, I would change ffmpeg to be an absolute path as well (in order to rule out path issues).
Edit: Further suggestions.
I would personally refactor the writing code into its own method, so that you can use it elsewhere necessary. In other other words:
public static boolean write(byte[] content, File to) {
FileOutputStream fos = new FileOutputStream(to);
try {
fos.write(content);
} catch (IOException io) {
// logging code here
return false;
} finally {
closeQuietly(fos);
}
return true;
}
public static void closeQuietly(Closeable toClose) {
if ( toClose == null ) { return; }
try {
toClose.close();
} catch (IOException e) {
// logging code here
}
}
The reason that I made the closeQuietly(Closeable) method is due to the fact that if you do not close it in that way, there is a possibility that an exception will be thrown by the close() method, and that exception will obscure the exception that was thrown originally. If you put these in a utility class (although looking at your code, I assume that the class that it is currently in is named FileUtils), then you will be able to use them throughout your application whenever you need to deal with file output.
This will allow you to rewrite the block as:
File file = new File(getUserFolderPath() + fileName + amr);
file.createNewFile()
write(Base64.decode(audio),file);
convertFile(fileName);
I don't know whether or not you should do this, however if you want to be sure that the ffmpeg process has completed, then you should say ffmpeg.waitFor(); to be sure that it has completed. If you do that, then you should examine ffmpeg.exitValue(); to make sure that it completed successfully.
Another thing that you might want to do is once it has completed, write what it output to a log file so you have a record of what happened, just in case something happens.

What is the best way, if possible, to send information from a Java PrintStream to a JTextPane?

In Java, I have a package that translates XML metadata from one standard to another. This package is ultimately accessed through a single function and sends all of its output through a PrintStream object. The output sent is just a status of each file and whether or not it was translated.
This is pretty fine and dandy if I'm just printing to System.out, but I'm actually wanting to print this to a JTextPane while it translates (kind of like a progress text box). It wouldn't be a big deal to just print the status after it was done translating the XML, but since there may be thousands of XML files, that's just not feasible.
One thing that I've tried is to use a thread that takes all of the information from the PrintStream (which is attached to a ByteArrayOutputStream) and let it send any new information to the text pane. Unfortunately, this still sends the information all at once at the end of the translation. This does work correctly for System.out.
Here's the code that does the translation and tries to show the output:
public class ConverterGUI extends javax.swing.JFrame {
boolean printToResultsBox = false;
PrintStream printStream = null;
ByteArrayOutputStream baos = null;
private class ResultsPrinter implements Runnable {
public ResultsPrinter() {
baos = new ByteArrayOutputStream();
printStream = new PrintStream(baos);
}
public void run() {
String tempString = "";
while (printToResultsBox) {
try {
if (!baos.toString().equals(tempString)) {
tempString = baos.toString();
resultsBox.setText(tempString);
}
} catch (Exception ex) {
}
}
}
}
...
ResultsPrinter rp = new ResultsPrinter();
Thread thread = new Thread(rp);
thread.start();
// Do the translation.
try {
printToResultsBox = true;
boolean success = false;
TranslationEngine te = new TranslationEngine();
// fileOrFolderToConvert is a text box in the GUI.
// linkNeeded and destinationFile are just parameters for the translation process.
success = te.translate(fileOrFolderToConvert.getText(), linkNeeded, destinationFile, printStream);
if (success) {
printStream.println("File/folder translation was a success.");
}
resultsBox.setText(baos.toString());
} catch (Exception ex) {
printStream.println("File translation failed.");
} finally {
printToResultsBox = false;
}
...
}
Ultimately, this code prints out to the JTextPane just fine after all the translation is done but not during. Any suggestions? Do I need to change the PrintStream to something else?

The problem with the way your thread works is you are not on the UI event thread when updating your results box. Take a look at the SwingWorker class. Or you could even use the SwingUtilities.invokeAndWait

How do I save a String to a text file using Java?

In Java, I have text from a text field in a String variable called "text".
How can I save the contents of the "text" variable to a file?

If you're simply outputting text, rather than any binary data, the following will work:
PrintWriter out = new PrintWriter("filename.txt");
Then, write your String to it, just like you would to any output stream:
out.println(text);
You'll need exception handling, as ever. Be sure to call out.close() when you've finished writing.
If you are using Java 7 or later, you can use the "try-with-resources statement" which will automatically close your PrintStream when you are done with it (ie exit the block) like so:
try (PrintWriter out = new PrintWriter("filename.txt")) {
out.println(text);
}
You will still need to explicitly throw the java.io.FileNotFoundException as before.

Apache Commons IO contains some great methods for doing this, in particular FileUtils contains the following method:
static void writeStringToFile(File file, String data, Charset charset)
which allows you to write text to a file in one method call:
FileUtils.writeStringToFile(new File("test.txt"), "Hello File", Charset.forName("UTF-8"));
You might also want to consider specifying the encoding for the file as well.

In Java 7 you can do this:
String content = "Hello File!";
String path = "C:/a.txt";
Files.write( Paths.get(path), content.getBytes());
There is more info here:
http://www.drdobbs.com/jvm/java-se-7-new-file-io/231600403

Take a look at the Java File API
a quick example:
try (PrintStream out = new PrintStream(new FileOutputStream("filename.txt"))) {
out.print(text);
}

Just did something similar in my project. Use FileWriter will simplify part of your job. And here you can find nice tutorial.
BufferedWriter writer = null;
try
{
writer = new BufferedWriter( new FileWriter( yourfilename));
writer.write( yourstring);
}
catch ( IOException e)
{
}
finally
{
try
{
if ( writer != null)
writer.close( );
}
catch ( IOException e)
{
}
}

Use FileUtils.writeStringToFile() from Apache Commons IO. No need to reinvent this particular wheel.

In Java 11 the java.nio.file.Files class was extended by two new utility methods to write a string into a file. The first method (see JavaDoc here) uses the charset UTF-8 as default:
Files.writeString(Path.of("my", "path"), "My String");
And the second method (see JavaDoc here) allows to specify an individual charset:
Files.writeString(Path.of("my", "path"), "My String", StandardCharset.ISO_8859_1);
Both methods have an optional Varargs parameter for setting file handling options (see JavaDoc here). The following example would create a non-existing file or append the string to an existing one:
Files.writeString(Path.of("my", "path"), "String to append", StandardOpenOption.CREATE, StandardOpenOption.APPEND);

You can use the modify the code below to write your file from whatever class or function is handling the text. One wonders though why the world needs a new text editor...
import java.io.*;
public class Main {
public static void main(String[] args) {
try {
String str = "SomeMoreTextIsHere";
File newTextFile = new File("C:/thetextfile.txt");
FileWriter fw = new FileWriter(newTextFile);
fw.write(str);
fw.close();
} catch (IOException iox) {
//do stuff with exception
iox.printStackTrace();
}
}
}

I prefer to rely on libraries whenever possible for this sort of operation. This makes me less likely to accidentally omit an important step (like mistake wolfsnipes made above). Some libraries are suggested above, but my favorite for this kind of thing is Google Guava. Guava has a class called Files which works nicely for this task:
// This is where the file goes.
File destination = new File("file.txt");
// This line isn't needed, but is really useful
// if you're a beginner and don't know where your file is going to end up.
System.out.println(destination.getAbsolutePath());
try {
Files.write(text, destination, Charset.forName("UTF-8"));
} catch (IOException e) {
// Useful error handling here
}

Using Java 7:
public static void writeToFile(String text, String targetFilePath) throws IOException
{
Path targetPath = Paths.get(targetFilePath);
byte[] bytes = text.getBytes(StandardCharsets.UTF_8);
Files.write(targetPath, bytes, StandardOpenOption.CREATE);
}

In case if you need create text file based on one single string:
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;
public class StringWriteSample {
public static void main(String[] args) {
String text = "This is text to be saved in file";
try {
Files.write(Paths.get("my-file.txt"), text.getBytes());
} catch (IOException e) {
e.printStackTrace();
}
}
}

Use Apache Commons IO api. Its simple
Use API as
FileUtils.writeStringToFile(new File("FileNameToWrite.txt"), "stringToWrite");
Maven Dependency
<dependency>
<groupId>commons-io</groupId>
<artifactId>commons-io</artifactId>
<version>2.4</version>
</dependency>

Use this, it is very readable:
import java.nio.file.Files;
import java.nio.file.Paths;
Files.write(Paths.get(path), lines.getBytes(), StandardOpenOption.WRITE);

import java.io.*;
private void stringToFile( String text, String fileName )
{
try
{
File file = new File( fileName );
// if file doesnt exists, then create it
if ( ! file.exists( ) )
{
file.createNewFile( );
}
FileWriter fw = new FileWriter( file.getAbsoluteFile( ) );
BufferedWriter bw = new BufferedWriter( fw );
bw.write( text );
bw.close( );
//System.out.println("Done writing to " + fileName); //For testing
}
catch( IOException e )
{
System.out.println("Error: " + e);
e.printStackTrace( );
}
} //End method stringToFile
You can insert this method into your classes. If you are using this method in a class with a main method, change this class to static by adding the static key word. Either way you will need to import java.io.* to make it work otherwise File, FileWriter and BufferedWriter will not be recognized.

You could do this:
import java.io.*;
import java.util.*;
class WriteText
{
public static void main(String[] args)
{
try {
String text = "Your sample content to save in a text file.";
BufferedWriter out = new BufferedWriter(new FileWriter("sample.txt"));
out.write(text);
out.close();
}
catch (IOException e)
{
System.out.println("Exception ");
}
return ;
}
};

Using org.apache.commons.io.FileUtils:
FileUtils.writeStringToFile(new File("log.txt"), "my string", Charset.defaultCharset());

If you only care about pushing one block of text to file, this will overwrite it each time.
JFileChooser chooser = new JFileChooser();
int returnVal = chooser.showSaveDialog(this);
if (returnVal == JFileChooser.APPROVE_OPTION) {
FileOutputStream stream = null;
PrintStream out = null;
try {
File file = chooser.getSelectedFile();
stream = new FileOutputStream(file);
String text = "Your String goes here";
out = new PrintStream(stream);
out.print(text); //This will overwrite existing contents
} catch (Exception ex) {
//do something
} finally {
try {
if(stream!=null) stream.close();
if(out!=null) out.close();
} catch (Exception ex) {
//do something
}
}
}
This example allows the user to select a file using a file chooser.

Basically the same answer as here, but easy to copy/paste, and it just works ;-)
import java.io.FileWriter;
public void saveToFile(String data, String filename) {
try (
FileWriter fw = new FileWriter(filename)) {
fw.write(data);
} catch (Exception e) {
throw new RuntimeException(e);
}
}

private static void generateFile(String stringToWrite, String outputFile) {
try {
FileWriter writer = new FileWriter(outputFile);
writer.append(stringToWrite);
writer.flush();
writer.close();
log.debug("New File is generated ==>"+outputFile);
} catch (Exception exp) {
log.error("Exception in generateFile ", exp);
}
}

It's better to close the writer/outputstream in a finally block, just in case something happen
finally{
if(writer != null){
try{
writer.flush();
writer.close();
}
catch(IOException ioe){
ioe.printStackTrace();
}
}
}

I think the best way is using Files.write(Path path, Iterable<? extends CharSequence> lines, OpenOption... options):
String text = "content";
Path path = Paths.get("path", "to", "file");
Files.write(path, Arrays.asList(text));
See javadoc:
Write lines of text to a file. Each line is a char sequence and is
written to the file in sequence with each line terminated by the
platform's line separator, as defined by the system property
line.separator. Characters are encoded into bytes using the specified
charset.
The options parameter specifies how the the file is created or opened.
If no options are present then this method works as if the CREATE,
TRUNCATE_EXISTING, and WRITE options are present. In other words, it
opens the file for writing, creating the file if it doesn't exist, or
initially truncating an existing regular-file to a size of 0. The
method ensures that the file is closed when all lines have been
written (or an I/O error or other runtime exception is thrown). If an
I/O error occurs then it may do so after the file has created or
truncated, or after some bytes have been written to the file.
Please note. I see people have already answered with Java's built-in Files.write, but what's special in my answer which nobody seems to mention is the overloaded version of the method which takes an Iterable of CharSequence (i.e. String), instead of a byte[] array, thus text.getBytes() is not required, which is a bit cleaner I think.

If you wish to keep the carriage return characters from the string into a file
here is an code example:
jLabel1 = new JLabel("Enter SQL Statements or SQL Commands:");
orderButton = new JButton("Execute");
textArea = new JTextArea();
...
// String captured from JTextArea()
orderButton.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent ae) {
// When Execute button is pressed
String tempQuery = textArea.getText();
tempQuery = tempQuery.replaceAll("\n", "\r\n");
try (PrintStream out = new PrintStream(new FileOutputStream("C:/Temp/tempQuery.sql"))) {
out.print(tempQuery);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
System.out.println(tempQuery);
}
});

I have published a library that saves files, and handles everything with one line of code only, you can find it here along with its documentation
Github repository
and the answer to your question is so easy
String path = FileSaver
.get()
.save(string.getBytes(),"file.txt");

My way is based on stream due to running on all Android versions and needs of fecthing resources such as URL/URI, any suggestion is welcome.
As far as concerned, streams (InputStream and OutputStream) transfer binary data, when developer goes to write a string to a stream, must first convert it to bytes, or in other words encode it.
public boolean writeStringToFile(File file, String string, Charset charset) {
if (file == null) return false;
if (string == null) return false;
return writeBytesToFile(file, string.getBytes((charset == null) ? DEFAULT_CHARSET:charset));
}
public boolean writeBytesToFile(File file, byte[] data) {
if (file == null) return false;
if (data == null) return false;
FileOutputStream fos;
BufferedOutputStream bos;
try {
fos = new FileOutputStream(file);
bos = new BufferedOutputStream(fos);
bos.write(data, 0, data.length);
bos.flush();
bos.close();
fos.close();
} catch (IOException e) {
e.printStackTrace();
Logger.e("!!! IOException");
return false;
}
return true;
}

Develop Reference

Java is a programming language and computing platform first released by Sun Microsystems in 1995.

Proper Way to exit JAVA application after flie write - java

Java applications that create a UI don't terminate until certain conditions are met. For a JavaFX application, make sure you are closing all Stage instances.

Try putting the close in a finally block like below and see if it makes any difference. try { } catch (Exception e) { } finally { fileWriter.close(); }

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