Copy in java (copy files from D drive to E drive)

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

public class CopyTestDToE {

public static void main(String[] args) {
String DoldPath="D:\\a.jpg";
String EnewPath="E:\\"+System.nanoTime()+".jpg";
copyFile(DoldPath,EnewPath);
}

private static void copyFile(String DoldPath, String EnewPath) {
FileInputStream fis=null;

FileOutputStream fos=null;


try {
fis=new FileInputStream(new File(DoldPath));
fos=new FileOutputStream(new File(EnewPath));

byte[] bytes=new byte[1024];

int num=0;

while((num=fis.read(bytes))!=-1){
fos.write(bytes,0,num);
fos.flush();
}

System.out.println("复制完成");

} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} finally{
try {
fos.close();
fis.close();
} catch (IOException e) {
e.printStackTrace();
}
}

}

}