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

Posted by: admin November 2, 2017 Leave a comment

Questions:

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?

Answers:

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.

Questions:
Answers:

Apache Commons IO contains some great methods for doing this, in particular FileUtils contains the following method:

static void writeStringToFile(File file, String data) 

which allows you to write text to a file in one method call:

FileUtils.writeStringToFile(new File("test.txt"), "Hello File");

You might also want to consider specifying the encoding for the file as well.

Questions:
Answers:

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)
    {
    }
}

Questions:
Answers:

Take a look at the Java File API

a quick example:

try (PrintStream out = new PrintStream(new FileOutputStream("filename.txt"))) {
    out.print(text);
}

Questions:
Answers:

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

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Answers:

In Java 7 you can do this:

String content = "Hello File!";
String path = "C:/a.txt";
Files.write( Paths.get(path), content.getBytes(), StandardOpenOption.CREATE);

There is more info here:
http://www.drdobbs.com/jvm/java-se-7-new-file-io/231600403

Questions:
Answers:

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();
        }
    }
}

Questions:
Answers:

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>

Questions:
Answers:
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.

Questions:
Answers:

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
}

Questions:
Answers:

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 ;
    }
};

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Answers:

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);

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Answers:

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);
}

Questions:
Answers:

Using org.apache.commons.io.FileUtils:

FileUtils.writeStringToFile(new File("log.txt"), "my string", Charset.defaultCharset());

Questions:
Answers:

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();
        }
    }
}

Questions:
Answers:

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.

Questions:
Answers:

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();
     }
   }
}

Questions:
Answers:

You can use the ArrayList to put all the contents of the TextArea for exemple, and send as parameter by calling the save, as the writer just wrote string lines, then we use the “for” line by line to write our ArrayList in the end we will be content TextArea in txt file. if something does not make sense, I’m sorry is google translator and I who do not speak English.

Watch the Windows Notepad, it does not always jump lines, and shows all in one line, use Wordpad ok.


private void SaveActionPerformed(java.awt.event.ActionEvent evt) {

String NameFile = Name.getText();
ArrayList< String > Text = new ArrayList< String >();

Text.add(TextArea.getText());

SaveFile(NameFile, Text);

}


public void SaveFile(String name, ArrayList< String> message) {

path = "C:\Users\Paulo Brito\Desktop\" + name + ".txt";

File file1 = new File(path);

try {

    if (!file1.exists()) {

        file1.createNewFile();
    }


    File[] files = file1.listFiles();


    FileWriter fw = new FileWriter(file1, true);

    BufferedWriter bw = new BufferedWriter(fw);

    for (int i = 0; i < message.size(); i++) {

        bw.write(message.get(i));
        bw.newLine();
    }

    bw.close();
    fw.close();

    FileReader fr = new FileReader(file1);

    BufferedReader br = new BufferedReader(fr);

    fw = new FileWriter(file1, true);

    bw = new BufferedWriter(fw);

    while (br.ready()) {

        String line = br.readLine();

        System.out.println(line);

        bw.write(line);
        bw.newLine();

    }
    br.close();
    fr.close();

} catch (IOException ex) {
    ex.printStackTrace();
    JOptionPane.showMessageDialog(null, "Error in" + ex);        

}