FileCopy.java Source code

Introduction

Here is the source code for FileCopy.java

Source

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;

public class FileCopy {
    public static void main(String[] args) {
        try {
            copy("fromFile.txt", "toFile.txt");
        } catch (IOException e) {
            System.err.println(e.getMessage());
        }
    }

    public static void copy(String fromFileName, String toFileName) throws IOException {
        File fromFile = new File(fromFileName);
        File toFile = new File(toFileName);

        if (!fromFile.exists())
            throw new IOException("FileCopy: " + "no such source file: " + fromFileName);
        if (!fromFile.isFile())
            throw new IOException("FileCopy: " + "can't copy directory: " + fromFileName);
        if (!fromFile.canRead())
            throw new IOException("FileCopy: " + "source file is unreadable: " + fromFileName);

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

        if (toFile.exists()) {
            if (!toFile.canWrite())
                throw new IOException("FileCopy: " + "destination file is unwriteable: " + toFileName);
            System.out.print("Overwrite existing file " + toFile.getName() + "? (Y/N): ");
            System.out.flush();
            BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
            String response = in.readLine();
            if (!response.equals("Y") && !response.equals("y"))
                throw new IOException("FileCopy: " + "existing file was not overwritten.");
        } else {
            String parent = toFile.getParent();
            if (parent == null)
                parent = System.getProperty("user.dir");
            File dir = new File(parent);
            if (!dir.exists())
                throw new IOException("FileCopy: " + "destination directory doesn't exist: " + parent);
            if (dir.isFile())
                throw new IOException("FileCopy: " + "destination is not a directory: " + parent);
            if (!dir.canWrite())
                throw new IOException("FileCopy: " + "destination directory is unwriteable: " + parent);
        }

        FileInputStream from = null;
        FileOutputStream to = null;
        try {
            from = new FileInputStream(fromFile);
            to = new FileOutputStream(toFile);
            byte[] buffer = new byte[4096];
            int bytesRead;

            while ((bytesRead = from.read(buffer)) != -1)
                to.write(buffer, 0, bytesRead); // write
        } finally {
            if (from != null)
                try {
                    from.close();
                } catch (IOException e) {
                    ;
                }
            if (to != null)
                try {
                    to.close();
                } catch (IOException e) {
                    ;
                }
        }
    }
}