Java Copy File using Files.copy()

Tags: Files.copy Java NIO

In this Java NIO tutorial we learn how to use the Files.copy() method to copy files in Java program. With different detail example Java programs we show you how to copy file to destination location, or copy an InputStream to a file, copy a file to an OutputStream.

Table of contents

  1. How to use Files.copy() method to copy file in Java
  2. More Files.copy() Java Examples

How to use Files.copy() method to copy file in Java

For example we have a file at D:\Folder1\image.png and want to copy it to another directory at D:\Folder2\image.png , we can use Files.copy() method as following Java program.

FilesCopyExample1.java 

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

public class FilesCopyExample1 {
    public static void main(String... args) throws IOException {
        Path sourceFile = Paths.get("D:\\Folder1\\image.png");
        Path destinationFile = Paths.get("D:\\Folder2\\image.png");

        Path copiedFile = Files.copy(sourceFile, destinationFile);

        System.out.println("Successful copy file to " + copiedFile.toString());
    }
}
The output as below. 
Successful copy file to D:\Folder2\image.png

In case the destination location already existing the file your application may get the java.nio.file.FileAlreadyExistsException exception as below. 

Exception in thread "main" java.nio.file.FileAlreadyExistsException: D:\Folder2\image.png
	at sun.nio.fs.WindowsFileCopy.copy(WindowsFileCopy.java:124)
	at sun.nio.fs.WindowsFileSystemProvider.copy(WindowsFileSystemProvider.java:278)
	at java.nio.file.Files.copy(Files.java:1274)
	at FilesCopyExample1.main(FilesCopyExample1.java:11)

To allow the Java application replace the existing file if it exists we can call the Files.copy() method with StandardCopyOption.REPLACE_EXISTING parameter as example Java program below.

FilesCopyExample2.java 

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

public class FilesCopyExample2 {
    public static void main(String... args) throws IOException {
        Path sourceFile = Paths.get("D:\\Folder1\\image.png");
        Path destinationFile = Paths.get("D:\\Folder2\\image.png");

        Path copiedFile = Files.copy(sourceFile, destinationFile, StandardCopyOption.REPLACE_EXISTING);

        System.out.println("Successful copy file to " + copiedFile.toString());
    }
}
The output as below. 
Successful copy file to D:\Folder2\image.png

More Files.copy() Java Examples

Copy FileInputStream to File using Files.copy()

Using the using Files.copy() method we also can copy all bytes in an InputStream into a file. In the following Java program we will copy a FileInputStream to a destination file location.

FilesCopyExample3.java 

import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;

public class FilesCopyExample3 {
    public static void main(String... args) throws IOException {
        InputStream inputStream = new FileInputStream("D:\\Folder1\\image.png");
        Path destinationFile = Paths.get("D:\\Folder2\\image.png");

        long numberOfBytes = Files.copy(inputStream, destinationFile, StandardCopyOption.REPLACE_EXISTING);

        System.out.println("Successful copy " + numberOfBytes + " bytes " + destinationFile.toString());
    }
}
The output as below. 
Successful copy 390 bytes D:\Folder2\image.png

Copy ByteArrayInputStream to File using Files.copy()

Or we can copy all bytes from a ByteArrayInputStream to file as below Java program.

FilesCopyExample4.java 

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;
import java.nio.file.StandardCopyOption;

public class FilesCopyExample4 {
    public static void main(String... args) throws IOException {
        String valueToCopy = "Simple Solution";
        InputStream inputStream = new ByteArrayInputStream(valueToCopy.getBytes());
        Path destinationFile = Paths.get("D:\\Folder2\\text-file.txt");

        long numberOfBytes = Files.copy(inputStream, destinationFile, StandardCopyOption.REPLACE_EXISTING);

        System.out.println("Successful copy " + numberOfBytes + " bytes " + destinationFile.toString());
    }
}
The output as below. 
Successful copy 15 bytes D:\Folder2\text-file.txt

Copy File to FileOutputStream using Files.copy()

The Files.copy() method allow to copy file to an OutputStream.

In the following Java program, we show you how to copy all bytes of a file to a destination FileOutputStream.

FilesCopyExample5.java 

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

public class FilesCopyExample5 {
    public static void main(String... args) throws IOException {
        Path sourceFile = Paths.get("D:\\Folder1\\image.png");
        OutputStream outputStream = new FileOutputStream("D:\\Folder2\\image.png");

        long numberOfBytes = Files.copy(sourceFile, outputStream);

        System.out.println("Successful copy " + numberOfBytes + " bytes to the OutputStream");
    }
}
The output as below. 
Successful copy 390 bytes to the OutputStream

Copy File to ByteArrayOutputStream using Files.copy()

The following Java program, we show you how to copy all bytes from a file to a ByteArrayOutputStream.

FilesCopyExample7.java 

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

public class FilesCopyExample7 {
    public static void main(String... args) throws IOException {
        Path sourceFile = Paths.get("D:\\Folder1\\Document.txt");
        ByteArrayOutputStream outputStream = new ByteArrayOutputStream();

        long numberOfBytes = Files.copy(sourceFile, outputStream);

        System.out.println("Successful copy " + numberOfBytes + " bytes ");
        System.out.println("Copied content:");
        System.out.println(new String(outputStream.toByteArray()));
    }
}
The output as below. 
Successful copy 15 bytes 
Copied content:
Simple Solution

Happy Coding 😊

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