Mega Code Archive
Copy files using Java IO API
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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) {
;
}
}
}
}
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