How to Save a String to a File in Java

1. Write a String to a File Using the PrintWriter Class in Java
2. Write a String to a File Using Java7 Files Class
3. Write a String to a File Using the FileWriter Class in Java

This article will introduce methods to write a string to a file in Java.

Write a String to a File Using the PrintWriter Class in Java

To write a string to a file, we can use the PrintWriter class. The constructor of the class creates a file with the specified name given as a parameter.

The constructor throws FileNotFoundException if the string does not exist, or if we cannot create the file, or if some other error occurs while opening or creating the file.

The println() function will print the string in the file and terminates a line.

The close() method will close the stream and relieves the system resources associated with it.

package writeStringToFile;

import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Objects;

public class WriteStringToFile {
  public static void main(String[] args) {
    PrintWriter printWriter = null;
    String textToBeWritten = "Hello";
    {
      try {
        printWriter = new PrintWriter("writerFile.txt");
      } catch (FileNotFoundException e) {
        System.out.println("Unable to locate the fileName: " + e.getMessage());
      }
      Objects.requireNonNull(printWriter).println(textToBeWritten);
      printWriter.close();
    }
  }
}

Write a String to a File Using Java7 Files Class

The Files class consists exclusively of static methods that operate on files, directories, or other types of files. The write() method writes bytes to a file. The options parameters specify how the file is created or opened. If no options are present, this method works as if the CREATE, TRUNCATE_EXISTING, and WRITE options are already there.

The method takes two parameters, path and bytes.

The path specifies the path of the target file. The getBytes() method converts the string into the Byte format.

The method throws IOException if an error occurs while writing or creating a file.

package writeStringToFile;

import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Paths;

public class WriteStringToFileJava7 {
  public static void main(String[] args) throws IOException {
    String contentToWrite = "Hello File!";
    String path =
        "C:\IdeaProjects\JavaProblems\src\main\java\writeStringToFile\target\targetFile.txt";
    Files.write(Paths.get(path), contentToWrite.getBytes());
  }
}

Write a String to a File Using the FileWriter Class in Java

The BufferedWriter class creates a buffered character-output stream that uses a default-sized output buffer. It takes any writer object as a parameter. The FileWriter class constructor takes the file name, which is the target to store the string. The write method writes the text to the associated file in the object. This method throws IOException when the file is not locatable.

Now in the finally block, one should release the resources for input and output operations. The close method further throws the IOException class, so we should either use the close function in the try-catch block or add the throws clause in the parent method.

package writeStringToFile;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;

public class WriteToFileUsingFileWriter {
  public static void main(String[] args) throws IOException {
    BufferedWriter bufferedWriter = null;
    try {
      bufferedWriter = new BufferedWriter(new FileWriter("targetFile.txt"));
      bufferedWriter.write("Hey! Content to write in File");

    } catch (IOException e) {
      System.out.println("Exception occurred: " + e.getMessage());

    } finally {
      if (bufferedWriter != null)
        bufferedWriter.close();
    }
  }
}