FILE Operation - Program

import java.io.*;

class demo1

{

public static void main(String args[]) throws IOException

{

char ch;

String str;

System.out.println("\nA.Filehandling\nB.Fileout\nC.Filein\n D.Fileread\nE.Filewrite\nF.Filerename and delete");

System.out.println("\n\nEnter your choice");

ch=(char)System.in.read();

switch(ch)

{

case 'a':

// To get some lines of text as input and writing it in another file. try

{

File f1=new File(args[0]);

System.out.println("file name:"+f1.getName());

System.out.println("path:"+f1.getPath());

System.out.println("Absolute Path:" +f1.getAbsolutePath());

System.out.println(f1.exists()?"file exists":"file does not exists");

System.out.println(f1.is Directory()?"fileisa directory":"file is not a directory");

System.out.println(f1.isFile()?"file is an ordinary file":"file may be a named pipe");

}

catch(ArrayIndexOutOfBoundsException e)

{

System.out.println("Enter the file name to be searched as a command line argument.");

}

break;

case 'b':// To read a file and displaying the contents on the console.

try

{

InputStreamReader isr=new InputStreamReader(System.in);

BufferedReader br=new BufferedReader(isr);

FileOutputStream fos=new FileOutputStream(args[0]);

System.out.println("Enter lines of text. Type stop to finish the process.");

while(true)

{

str=br.readLine();

if(str.equals("stop"))

break;

str=str+"\r\n";

byte buf[]=str.getBytes();

fos.write(buf);

}

fos.close();

System.out.println("Contents written to "+args[0]);

}

catch(IOException e)

{

System.out.println("Exception Caught: "+e);

}

catch(ArrayIndexOutOfBoundsException e)

{

System.out.println("Enter the name of the output file as a command line argument.");

}

break;

case 'c':

// To read a file and displaying the contents on the console, using //FileReader.

try

{

FileInputStream fis=new FileInputStream(args[0]);

int size=fis.available();

for (int i=0;i

System.out.print((char)fis.read());

fis.close();

}

catch(ArrayIndexOutOfBoundsException e)

{

System.out.println("Enter the file name to be read as a command line argument.");

}

catch(FileNotFoundException e)

{

System.out.println("File not found.");

}

break;

case 'd'://To copy the contents of a file to another file, using FileWriter.

try

{

FileReader fr=new FileReader(args[0]);

BufferedReader br=new BufferedReader(fr);

while((str=br.readLine())!=null)

System.out.println(str);

fr.close();

}

catch(FileNotFoundException e)

{

System.out.println("Exception Caught: "+e);

}

catch(ArrayIndexOutOfBoundsException e)

{

System.out.println("Enter the name of the input file as a command line argument.");

}

break;

case 'e':// To rename and deleting a file.

try

{

FileReader fr=new FileReader(args[0]);

BufferedReader br=new BufferedReader(fr);

FileWriter fw=new FileWriter(args[1]);

while((str=br.readLine())!=null)

{

str=str+"\r\n";

char buf[]=new char[str.length()];

str.getChars(0,str.length(),buf,0);

fw.write(buf);

}

fr.close();

fw.close();

System.out.println("File Writer process finished successfully.");

}

catch(ArrayIndexOutOfBoundsException e)

{

System.out.println("Enter the names of the input file and output file as a command line argument.");

}

break;

case 'f':

if(args.length==2)

{

File f=new File(args[0]);

File f1=new File(args[1]);

if(f.exists())

{

System.out.println(f+" does exists."); System.out.println("Its size is "+f.length()+" bytes");

f.renameTo(f1);

System.out.println("Renamed file name: "+f1 );

System.out.println("deleting the renamed file "+f);

System.out.println("**********************");

f.delete();

}

else

System.out.println(f+" does not exists");

}

else

System.out.println("Enter the file name to be renamed and the new name of the file as a command line argument.");

break;

default:

System.out.println("Enter the correct choice");

break;

}

}

}

OUTPUT:

Z:\jdk1.5\bin>javac demo1.java

Z:\jdk1.5\bin>java demo1 "input.txt"

A.Filehandling

B.Fileout

C.Filein

D.Fileread

E.Filewrite

F.Filerename and delete

Enter your choice a

file name:input.txt

path:input.txt

Absolute path:Z:\jdk1.5\bin\input.txt

file exists

file is not a directory

file is an ordinary file

Z:\jdk1.5\bin>java demo1 "input.txt"

A.Filehandling

B.Fileout

C.Filein

D.Fileread

E.Filewrite

F.Filerename and delete

Enter your choice b

Enter lines of text. Type stop to finish the process.

java programming

stop

Contents written to input.txt

Z:\jdk1.5\bin>java demo1 "input.txt"

A.Filehandling

B.Fileout

C.Filein

D.Fileread

E.Filewrite

F.Filerename and delete

Enter your choice c

java programming

Z:\jdk1.5\bin>java demo1 "input.txt" "out.txt"

A.Filehandling

B.Fileout

C.Filein

D.Fileread

E.Filewrite

F.Filerename and delete

Enter your choice e

File Writer process finished successfully.

Z:\jdk1.5\bin>java demo1 "input.txt" "in.txt"

A.Filehandling

B.Fileout

C.Filein

D.Fileread

E.Filewrite

F.Filerename and delete

Enter your choice f

input.txt does exists.

Its size is 20 bytes

Renamed file name: in.txt

deleting the renamed file input.txt