Java get file size With Examples [Latest]

Java get file size

There are different classes that we can use for java get file size program. Some of them are;

Java get file size using File class
Get file size in java using FileChannel class
Java get file size using Apache Commons IO FileUtils class

Before we look into an example program to get file size, we have a sample pdf file with size 2969575 bytes.

java-file-size

Java get file size using `File` class

Java File length() method returns the file size in bytes. The return value is unspecified if this file denotes a directory. So before calling this method to get file size in java, make sure file exists and it’s not a directory.

Below is a simple java get file size example program using File class.


package com.journaldev.getfilesize;
import java.io.File;
public class JavaGetFileSize {
	static final String FILE_NAME = "/Users/pankaj/Downloads/file.pdf";
	public static void main(String[] args) {
		File file = new File(FILE_NAME);
		if (!file.exists() || !file.isFile()) return;
		System.out.println(getFileSizeBytes(file));
		System.out.println(getFileSizeKiloBytes(file));
		System.out.println(getFileSizeMegaBytes(file));
	}
	private static String getFileSizeMegaBytes(File file) {
		return (double) file.length() / (1024 * 1024) + " mb";
	}
	private static String getFileSizeKiloBytes(File file) {
		return (double) file.length() / 1024 + "  kb";
	}
	private static String getFileSizeBytes(File file) {
		return file.length() + " bytes";
	}
}
<img class="alignnone wp-image-31649 size-full" src="https://all-learning.com/wp-content/uploads/2012/12/java-get-file-sizes.png" alt="java-get-file-size" width="1200" height="864" />

package com.journaldev.getfilesize;

import java.io.File;

public class JavaGetFileSize {

static final String FILE_NAME = "/Users/pankaj/Downloads/file.pdf";

public static void main(String[] args) {

File file = new File(FILE_NAME);

if (!file.exists() || !file.isFile()) return;

System.out.println(getFileSizeBytes(file));

System.out.println(getFileSizeKiloBytes(file));

System.out.println(getFileSizeMegaBytes(file));

}

private static String getFileSizeMegaBytes(File file) {

return (double) file.length() / (1024 * 1024) + " mb";

}

private static String getFileSizeKiloBytes(File file) {

return (double) file.length() / 1024 + " kb";

}

private static String getFileSizeBytes(File file) {

return file.length() + " bytes";

}

Get file size in java using `FileChannel` class

We can use FileChannel size() method to get file size in bytes.


package com.journaldev.getfilesize;
import java.io.IOException;
import java.nio.channels.FileChannel;
import java.nio.file.Path;
import java.nio.file.Paths;
public class JavaGetFileSizeUsingFileChannel {
	static final String FILE_NAME = "/Users/pankaj/Downloads/file.pdf";
	public static void main(String[] args) {
		Path filePath = Paths.get(FILE_NAME);
		FileChannel fileChannel;
		try {
			fileChannel = FileChannel.open(filePath);
			long fileSize = fileChannel.size();
			System.out.println(fileSize + " bytes");
			fileChannel.close();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

package com.journaldev.getfilesize;

import java.io.IOException;

import java.nio.channels.FileChannel;

import java.nio.file.Path;

import java.nio.file.Paths;

public class JavaGetFileSizeUsingFileChannel {

static final String FILE_NAME = "/Users/pankaj/Downloads/file.pdf";

public static void main(String[] args) {

Path filePath = Paths.get(FILE_NAME);

FileChannel fileChannel;

try {

fileChannel = FileChannel.open(filePath);

long fileSize = fileChannel.size();

System.out.println(fileSize + " bytes");

fileChannel.close();

} catch (IOException e) {

e.printStackTrace();

}

Java get file size using Apache Commons IO `FileUtils` class

If you are already using Apache Commons IO in your project, then you can use FileUtils sizeOf method to get file size in java.


package com.journaldev.getfilesize;
import java.io.File;
import org.apache.commons.io.FileUtils;
public class JavaGetFileSizeUsingApacheCommonsIO {
	static final String FILE_NAME = "/Users/pankaj/Downloads/file.pdf";
	public static void main(String[] args) {
		File file = new File(FILE_NAME);
		long fileSize = FileUtils.sizeOf(file);
		System.out.println(fileSize + " bytes");
	}
}

package com.journaldev.getfilesize;

import java.io.File;

import org.apache.commons.io.FileUtils;

public class JavaGetFileSizeUsingApacheCommonsIO {

static final String FILE_NAME = "/Users/pankaj/Downloads/file.pdf";

public static void main(String[] args) {

File file = new File(FILE_NAME);

long fileSize = FileUtils.sizeOf(file);

System.out.println(fileSize + " bytes");

}

That’s all for java get file size programs.

Java get file size With Examples [Latest]

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