Copy and overwrite files : File Commands « File Input Output « Java

Copy and overwrite files

//  Ahy - A pure java CMS.
//  Copyright (C) 2010 Sidney Leal (
//  This program is free software: you can redistribute it and/or modify
//  it under the terms of the GNU General Public License as published by
//  the Free Software Foundation, either version 3 of the License, or
//  (at your option) any later version.
//  This program is distributed in the hope that it will be useful,
//  but WITHOUT ANY WARRANTY; without even the implied warranty of
//  GNU General Public License for more details.
//  You should have received a copy of the GNU General Public License
//  along with this program.  If not, see <>.



public final class FileUtil {

    public static void copyFile(String from, String to) {
        copyFile(from, to, Boolean.FALSE);

    public static void copyFile(String from, String to, Boolean overwrite) {

        try {
            File fromFile = new File(from);
            File toFile = new File(to);

            if (!fromFile.exists()) {
                throw new IOException("File not found: " + from);
            if (!fromFile.isFile()) {
                throw new IOException("Can't copy directories: " + from);
            if (!fromFile.canRead()) {
                throw new IOException("Can't read file: " + from);

            if (toFile.isDirectory()) {
                toFile = new File(toFile, fromFile.getName());

            if (toFile.exists() && !overwrite) {
                throw new IOException("File already exists.");
            } else {
                String parent = toFile.getParent();
                if (parent == null) {
                    parent = System.getProperty("user.dir");
                File dir = new File(parent);
                if (!dir.exists()) {
                    throw new IOException("Destination directory does not exist: " + parent);
                if (dir.isFile()) {
                    throw new IOException("Destination is not a valid directory: " + parent);
                if (!dir.canWrite()) {
                    throw new IOException("Can't write on destination: " + parent);

            FileInputStream fis = null;
            FileOutputStream fos = null;
            try {

                fis = new FileInputStream(fromFile);
                fos = new FileOutputStream(toFile);
                byte[] buffer = new byte[4096];
                int bytesRead;

                while ((bytesRead = != -1) {
                    fos.write(buffer, 0, bytesRead);

            } finally {
                if (from != null) {
                    try {
                    } catch (IOException e) {
                if (to != null) {
                    try {
                    } catch (IOException e) {

        } catch (Exception e) {
            System.out.println("Problems when copying file.");



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