Files readString() API – Read file to string in Java

Learn to read a file to string in Java using Files.readString(path) method. This API has been introduced in Java 11.

1. Files readString() methods

java.nio.file.Files class has two overloaded methods.

public static String readString​(Path path) throws IOException

public static String readString​(Path path, Charset cs) throws IOException

• First method reads all content from a file into a string, decoding from bytes to characters using the UTF-8 charset.

  The method ensures that the file is closed when all content have been read or an I/O error, or other runtime exception, is thrown.

• First method is equivalent to readString(path, StandardCharsets.UTF_8).
• Second method does the same with with only using the specified charset.
• Please note that these methods are not intended for reading very large files. Otherwise they may throw OutOfMemoryError if the file is extremely large, e.g. larger than 2GB.

2. Files readString() example

Java program to read a file into string using Files.readString() method.

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

public class Main 
{
	public static void main(String[] args) 
	{
		Path filePath = Paths.get("C:/", "temp", "test.txt");

		try 
		{
			String content = Files.readString(filePath);

			System.out.println(content);
		} 
		catch (IOException e) 
		{
			e.printStackTrace();
		}
	}
}

Program output.

Hello Java Learner !!

Where the file c:/temp/test.txt is this.

Hello Java Learner !!

Drop me your questions in comments section.

Happy Learning !!