Java11 - Files methods

Java11 introduced two methods in Files Class

• readString()
• writeString()

How to read text file readString example?

Java11 provides Files readString method that read the string into a file with given encoding.

Syntax: readString read the file content as bytes and convert to String using UTF-8 encoding

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

In the first method, Read the file content into a string using default charset.

Arguments: This method takes java.nio.file.path as an argument Return: Return the string with all file content. Throws: IOException for IO exceptions, OutOfMemoryError for reading larger files size greater than 2GB.

CharSet is an CharSet to read

Here is an Java File Read example

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

public class JavaRead {
    public static void main(String[] args) {
        //Path object with given file in File System
        Path path
                = Paths.get("a:\\", "data.txt");
        try {
            String content = Files.readString(path);
            System.out.println(content);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

It prints the content of the file

Java writeString example

This is an example of writing string into a test file in java11.

Java11 provides Files writeString method that writes the string into a file.

    public static Path writeString(Path path, CharSequence csq, OpenOption... options)
    public static Path writeString(Path path, CharSequence csq, Charset cs, OpenOption... options)

Files WriteString has two overrided versions. First, path writes a string into a file using Path and default Charset. Second , writes a string into a file using CharSet and Options.

Here is an Java File Write example

Arguments: path: Path of an file in File System. CharSequence: charSequence or actual content in a string, write to a file. OpenOption: StandardOpenOption is an class that used here

It has below options

• READ
• WRITE
• APPEND
• TRUNCATE_EXISTING
• CREATE
• CREATE_NEW
• DELETE_ON_CLOSE
• SPARSE
• SYNC
• DSYNC StandardOpenOption.NEW used in the below example if new file need to create.

Here is an Java File Write example

import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardOpenOption;

public class JavaWrite {
    public static void main(String[] args) {
        //Path object with given file in File System
        Path path
                = Paths.get("a:\\", "test.txt");
        try {
            Files.writeString(path, "Test content inserted into a file", StandardOpenOption.CREATE);
            String content = Files.readString(path);

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