I have a simple project where I created a Store with customers, products and employees. Each is represented by a Class of course and I also have a CSV file for each one of them to be able to load data from and save data to it.
I'm facing issues where the file reading/writing is working, but not really. For example, I have the ability to save each file individually so if for instance I want to create a new customer, I'd save it to the list and then to the file. Issue is, once I do it for another Class (i.e if I create a new employee) and then save it again, the customer file object I saw in the CSV earlier is deleted. BUT, once I add a new object again, that same object reappears again. Hope you can somehow understand, but here is a more detailed view:
customer.csv is empty:
Me creating a new customer:
Created and saved to CSV:
Now, if I go to the other menu, and click on "Save all data" that jon snow customer object will be gone. Then if I create a new customer, then it will be added to the CSV file, along with the jon snow I added earlier. So why is it gone in the first place?
So here is the whole file reader/writer code I'm using:
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileWriter;
import java.util.ArrayList;
import java.io.IOException;
import java.util.List;
import java.util.Scanner;
class CSV {
static void CreateFile(String filename) { //Create new file
try {
File fileToCreate = new File(filename);
if (fileToCreate.createNewFile()) {
System.out.println("File created sucessfully: " + fileToCreate.getName());
}
} catch (IOException e) {
System.out.println("Cannot create file!");
}
}
static void ReadFile(String path_and_filename){
try {
File fileToRead = new File(path_and_filename);
Scanner myReader = new Scanner(fileToRead);
System.out.println("Reading file "+path_and_filename+" :");
while (myReader.hasNextLine()) {
String data = myReader.nextLine();
System.out.println(data);
}
myReader.close();
System.out.println();
} catch (FileNotFoundException e) {
System.out.println("There is no such file "+"\"path_and_filename\""+".\n");
}
}
// The StringBuilder in Java represents a mutable sequence of characters.
// Java's built in String class is not mutable.
static void saveArrayListToFile(List<Output> listToSave, String fileName, String sep) throws Exception {
StringBuilder ans = new StringBuilder();
for (Output record : listToSave) {
ans.append(record.createOutput());
ans.append(sep);
}
saveStringToFile(ans.toString(), fileName);
System.out.println("\nData saved to "+ fileName);
}
static void saveArrayListToFile1(ArrayList<String> listToSave, String fileName, String sep){
StringBuilder ans = new StringBuilder();
for (Object record : listToSave) {
ans.append(record.toString());
ans.append(sep);
}
saveStringToFile(ans.toString(), fileName);
System.out.println("\nList was saved to file "+fileName+"\n");
}
static void saveStringToFile(String data, String fileName){
BufferedWriter bufferedWriter=null;
try {
bufferedWriter = new BufferedWriter(
new FileWriter(fileName,false));
bufferedWriter.write(data);
} catch (IOException e) {
System.out.println("Cannot write to file");
} finally {
try {
bufferedWriter.close();
} catch (IOException e) {
System.out.println("Cannot write to file");
}
}
}
}
When I'm creating a new customer, I call it from a menu and it looks like this:
switch (selection) {
case 1:
try {
System.out.println("You're registering as a new customer");
String custID = ObjectIDs.generateID();
System.out.println("Enter first name:");
String firstName = sc.next();
System.out.println("Enter last name:");
String lastName = sc.next();
st.newCustomer(custID, firstName, lastName);
st.saveCustomersList();
} catch (Exception e) {
e.printStackTrace();
}
break;
the saveCustomerList() function is this:
#SuppressWarnings("unchecked")
void saveCustomersList() throws Exception {
CSV.saveArrayListToFile((List<Output>)(List<?>) customers, CUSTOMERS_FILE_PATH,"\n");
}
And then the functions calls saveArrayListToFile() to save it.
The behavior is the same with Product and Employee projects, so I randomly chose to show how it acts when creating a new Product.
I hope I added enough information. If needed, I can paste more code in but I already feel it's very cluttered. Hopefully it's ok.
Thank you very much :)
At the moment it's hard to say, as one can only hypothesise as to what happens when you click on "Save all data". There are some weird things (what is saveArrayListToFile and saveArrayListToFile11? Why does one declare an exception? When are these called?).
Having said that, look at the actual file writing method saveStringToFile, it says:
bufferedWriter = new BufferedWriter(new FileWriter(fileName,false));
This false there means 'do not append to file, rewrite it from scratch'. So each time you call it, file contents are discarded and replaced from what you provide to the method call. So my somewhat educated guess would be:
You save customer one to file (gets cleared, customer 1 written) and
append the customer to a list of customers (that's my guess)
You
save customer two to file (file gets cleared, so only customer 2 is
saved), you add to list to customers (do you?)
Then you choose 'save all' which gets list of customers, and save them in one go, a single call to the method. The file is cleared, all customers are saved.
But it's all guessing. Try creating a minimal, reproducible example
In addition to pafau k. I would like to add some things at least I would do differently...
First of all:
Things that can cause errors or unexpected behaviour:
Everything below is in saveStringToFile
Like already pointed out the Initialisation of the BufferedWriter: It should be initialized like this:
bufferedWriter = new BufferedWriter(new FileWriter(filename, true));
This puts the File into appending mode (if you want to append to a file you can also get rid of the boolean (second argument) entirely because appending is standard: new FileWriter(filename))
If for some case the Creation of the BufferedWriter failed you will still have a null-pointing object as bufferedWriter. This however means that you will be surprised with a NullPointerException in your finally block. To prevent this first of all do a check in your finally block:
if (bufferedWriter != null) {
// Close your bufferedWriter in here
}
Also, if you run into an error you will likely be presented with the same error message twice.
Now cosmetics:
Things that I would write differently for aesthetic reasons:
Java methods (and static "methods") are always starting with a small letter :)
This means it should be public static void createFile() for example or static void readFile()
variables and parameters of methods do not contain seperators like _ but instead if you want to make it more readable you start with a small letter and for each seperation you use a capital letter for that: e.g. String thisIsAVeryLongVariableWithALotOfSeperations = "Foo";
The generic types in saveArrayListToFile1() work like a placeholder. So you declare ArrayList<String> listToSave so you don't need a cast in the following for-loop: You can simply write:
for (String record : listToSave) {
ans.append(record);
ans.append(sep);
}
I hope this fixes all errors or complications. :)
Im trying to create a file if it doesnt exist, if it does exist append to it.
Is this the best way to do it? Im not sure having two try catches inside one method is good personally?
public static void main(String [] args)
{
String fileLocation = "/temp/";
String name = "Bob";
String timeStamp = "1988-03-15";
Path path = Paths.get(fileLocation+ "info.log");
if(!Files.exists(path)){
try {
Files.createFile(path);
} catch (IOException e) {
e.printStackTrace();
}
}
try (BufferedWriter writer = Files.newBufferedWriter(path, StandardCharsets.UTF_8, StandardOpenOption.APPEND)) {
SimpleDateFormat tTimeFormatter = new SimpleDateFormat("yyyy/MM/dd HH:mm:ss:SSS");
writer.write(tTimeFormatter.format(System.currentTimeMillis()) + " name: " + name + " Timestamp: "+ timeStamp);
writer.newLine();
} catch (IOException e) {
System.out.print(e.getStackTrace());
}
}
You can write to file with StandardOpenOptions: CREATE and APPEND.
Files.write(Paths.get(""), new byte[] {}, StandardOpenOption.CREATE, StandardOpenOption.APPEND);
CREATE - means if file doesn't exists it creates new one otherwise get existing.
APPEND - means append new data to existing content in file.
So, you can do all your operations with a single line.
The File.createNewFile() method creates a new, empty file named by this abstract pathname if and only if a file with this name does not yet exist. This methods return a true value if the file is created successfully and false if the file already exists or the operation failed.
if (myFile.createNewFile()){
System.out.println("File is created!");
}else{
System.out.println("File already exists.");
}
Try using the printWriter class like this
java.io.PrintWriter p = new java.io.PrintWriter(yourFileHere);
// You can use println to print a new line if it allready exists
p.println(yourTextHere);
// Or append to the end of the file
p.append("TEXT HERE!!!!")
I am writing a function to take a text file and count how many lines it has while outputting the lines to an array of strings. Doing this I have several exceptions I need to look out for. The class function has several variables that should have a scope throughout the function but when I write a value to the function inside of an exception, the return statement cannot find it. I've moved the declaration around and nothing helps
The value returned "h5Files" "Might not have been initialized" Since I don't know how long the array will be I cannot initialize it to a certain length. I do this within the code and I need a way to tell the return statement that I now have a values
Here is the code
public String[] ReadScanlist(String fileIn){
int i;
String directory ="c:\\data\\"; // "\" is an illegal character
System.out.println(directory);
int linereader = 0;
String h5Files[];
File fileToRead = new File(directory + fileIn);
System.out.println(fileToRead);
try {
FileInputStream fin = new FileInputStream(fileToRead); // open this file
}
catch(FileNotFoundException exc) {
System.out.println("File Not Found");
}
try{
//read bytes until EOF is detected
do {
FileReader fr = new FileReader(fileToRead);// Need to convert to reader
LineNumberReader lineToRead = new LineNumberReader(fr); // Use line number reader class
//
while (lineToRead.readLine() != null){
linereader++;
}
linereader = 0;
lineToRead.setLineNumber(0); //reset line number
h5Files = new String[linereader];
while (lineToRead.readLine() != null){
h5Files[linereader] = lineToRead.readLine(); // deposit string into array
linereader++;
}
return h5Files;
}
while(i !=-1); // When i = -1 the end of the file has been reached
}
catch(IOException exc) {
System.out.println("Error reading file.");
}
try{
FileInputStream fin = new FileInputStream(fileToRead);
fin.close(); // close the file
}
catch(IOException exc) {
System.out.println("Error Closing File");
}
return h5Files;
}
Your code is very very odd. For example these two blocks make no sense:
try {
FileInputStream fin = new FileInputStream(fileToRead); // open this file
}
catch(FileNotFoundException exc) {
System.out.println("File Not Found");
}
try{
FileInputStream fin = new FileInputStream(fileToRead);
fin.close(); // close the file
}
catch(IOException exc) {
System.out.println("Error Closing File");
}
I don't know what you think they do, but besides the first one leaking memory, they do nothing at all. The comments are more worrying, they suggest that you need to do more reading on IO in Java.
Deleting those blocks and tidying the code a (moving declarations, formatting) gives this:
public String[] ReadScanlist(String fileIn) {
String directory = "c:\\data\\";
String h5Files[];
File fileToRead = new File(directory + fileIn);
try {
int i = 0;
do {
FileReader fr = new FileReader(fileToRead);
LineNumberReader lineToRead = new LineNumberReader(fr);
int linereader = 0;
while (lineToRead.readLine() != null) {
linereader++;
}
linereader = 0;
lineToRead.setLineNumber(0);
h5Files = new String[linereader];
while (lineToRead.readLine() != null) {
h5Files[linereader] = lineToRead.readLine();
linereader++;
}
return h5Files;
} while (i != -1);
} catch (IOException exc) {
System.out.println("Error reading file.");
}
return h5Files;
}
My first bone of contention is the File related code. First, File abstracts from the underlying OS, so using / is absolutely fine. Second, there is a reason File has a File, String constructor, this code should read:
File directory = new File("c:/data");
File fileToRead = new File(directory, fileIn);
But it should really be using the new Path API anyway (see below).
So, you declare h5Files[]. You then proceed to read the whole file to count the lines. You then assign h5Files[] to an array of the correct size. Finally you fill the array.
If you have an error anywhere before you assign h5Files[] you have not initialised it and therefore cannot return it. This is what the compiler is telling you.
I don't know what i does in this code, it is assigned to 0 at the top and then never reassigned. This is an infinite loop.
So, you need to rethink your logic. I would recommend throwing an IOException if you cannot read the file. Never return null - this is an anti-pattern and leads to all those thousands of null checks in your code. If you never return null you will never have to check for it.
May I suggest the following alternative code:
If you are on Java 7:
public String[] ReadScanlist(String fileIn) throws IOException {
final Path root = Paths.get("C:/data");
final List<String> lines = Files.readAllLines(root.resolve(fileIn), StandardCharsets.UTF_8);
return lines.toArray(new String[lines.size()]);
}
Or, if you have Java 8:
public String[] ReadScanlist(String fileIn) throws IOException {
final Path root = Paths.get("C:/data");
try (final Stream<String> lines = Files.lines(root.resolve(fileIn), StandardCharsets.UTF_8)) {
return lines.toArray(String[]::new);
}
}
Since I don't know how long the array will be I cannot initialize it
to a certain length.
I don't think an array is the correct solution for you then - not to say it can't be done, but you would be re-inventing the wheel.
I would suggest you use a LinkedList instead, something like:
LinkedList<String> h5Files = new LinkedList<>();
h5Files.add(lineToRead.readLine());
Alternatively you could re-invent the wheel by setting the array to an arbritary value, say 10, and then re-size it whenever it gets full, something like this:
h5Files = new String[10];
if (linereader = h5Files.size())
{
String[] temp = h5Files;
h5Files = new String[2 * linereader];
for (int i = 0; i < linereader; i++)
{
h5Files[i] = temp[i];
}
}
Either one of these solutions would allow you to initialize the array (or array alternative) in a safe constructor, prior to your try block, such that you can access it if any exceptions are thrown
Here is your problem. Please take a look on digested version of your code with my comments.
String h5Files[]; // here you define the variable. It still is not initialized.
try{
..................
do {
h5Files = new String[linereader]; // here you initialize the variable
} while(i !=-1); // When i = -1 the end of the file has been reached
..................
catch(IOException exc) {
// if you are here the variable is still not initialized
System.out.println("Error reading file.");
}
// you continue reading file even if exception was thrown while opening the file
I think that now the problem is clearer. You try to open the file and count lines. If you succeed you create array. If not (i.e. when exception is thrown) you catch the exception but still continue reading the file. But in this case you array is not initialized.
Now how to fix this?
Actually if you failed to read the file first time you cannot continue. This may happen for example if file does not exist. So, you should either return when first exception is thrown or just do not catch it at all. Indeed there is nothing to do with the file if exception was thrown at any phase. Exception is not return code. This is the reason that exceptions exist.
So, just do not catch exceptions at all. Declare your method as throws IOException and remove all try/catch blocks.
This is the code I use when I try to read some specific text in a *.txt file:
public void readFromFile(String filename, JTable table) {
BufferedReader bufferedReader = null;
try {
bufferedReader = new BufferedReader(new FileReader(filename));
String a,b,c,d;
for(int i=0; i<3; i++)
{
a = bufferedReader.readLine();
b = bufferedReader.readLine();
c = bufferedReader.readLine();
d = bufferedReader.readLine();
table.setValueAt(a, i, 0);
table.setValueAt(b, i, 1);
table.setValueAt(c, i, 2);
table.setValueAt(d, i, 3);
}
} catch (FileNotFoundException ex) {
ex.printStackTrace();
} catch (IOException ex) {
ex.printStackTrace();
} finally {
//Close the reader
try {
if (bufferedReader != null) {
bufferedReader.close();
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}
And it is called in this way:
readFromFile("C:/data/datafile.txt", table1)
The problem is the following: the 1st time I open the program the *.txt file I'm going to read does not exist, so I thought I could use the function exists(). I have no idea about what to do, but I tried this:
if(("C:/data/datafile.txt").exists()) {
readFromFile("C:/data/datafile.txt", table1)
}
It is not working because NetBeans gives me a lot of errors. How could I fix this?
String has no method named exists() (and even if it did it would not do what you require), which will be the cause of the errors reported by the IDE.
Create an instance of File and invoke exists() on the File instance:
if (new File("C:/data/datafile.txt").exists())
{
}
Note: This answer use classes that aren't available on a version less than Java 7.
The method exists() for the object String doesn't exist. See the String documentation for more information. If you want to check if a file exist base on a path you should use Path with Files to verify the existence of the file.
Path file = Paths.get("C:/data/datafile.txt");
if(Files.exists(file)){
//your code here
}
Some tutorial about the Path class : Oracle tutorial
And a blog post about How to manipulate files in Java 7
Suggestion for your code:
I'll point to you the tutorial about try-with-resources as it could be useful to you. I also want to bring your attention on Files#readAllLines as it could help you reduce the code for the reading operation. Based on this method you could use a for-each loop to add all the lines of the file on your JTable.
you can use this code to check if the file exist
Using java.io.File
File f = new File(filePathString);
if(f.exists()) { /* do something */ }
You need to give it an actual File object. You're on the right track, but NetBeans (and java, for that matter) has no idea what '("C:/data/datafile.txt")' is.
What you probably wanted to do there was create a java.io.File object using that string as the argument, like so:
File file = new File ("C:/data/datafile.txt");
if (file.exists()) {
readFromFile("C:/data/datafile.txt", table1);
}
Also, you were missing a semicolon at the end of the readFromFile call. Im not sure if that is just a typo, but you'll want to check on that as well.
If you know you're only ever using this File object just to check existence, you could also do:
if (new File("C:/data/datafile.txt").exists()) {
readFromFile("C:/data/datafile.txt", table1);
}
If you want to ensure that you can read from the file, it might even be appropriate to use:
if(new File("C:/data/datafile.txt").canRead()){
...
}
as a condition, in order to verify that the file exists and you have sufficient permissions to read from the file.
Link to canRead() javadoc
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;
}