I/O 1

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Buffered Byte Stream:

·       It is based on the byte oriented stream

·    The buffered byte stream classes are buffered I/p  

    and o/p stream.

BufferedInputStream

·       Buffered inputstream class allows you to “wrap” any inputstream into a buffered stream.this class implements the fileinputstream class.

·       To read the data from file using the Bufferedrinputstream.

BufferedOutputStream

·       Buffered output stream is similar to any outputstream.

·       Bufferedoutput stream is used to write the data to file.

·       The data are written into a internal buffer, otherwise the buffer reaches its capacity , the buffer output stream is closed or the buffer outputstream  is explicitly flushed.

Default buffer size : 512 bytes

Methods

write()              -       Writes the specified byte to the buffered output stream.

flush()             -       Flushes the buffered output stream.

// Bufferedinputstream   & Bufferedoutputstream

import java.io.*;

class FileIOdemo

{

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

 {

  int ch,fsize;

 File f=new File(args[0]);

//FileOutputStream f=new FileOutputStream(f,true)

  BufferedOutputStream bos=new BufferedOutputStream(new FileOutputStream(f,true));

  System.out.println("Enter a text : ");

  do

  {

   ch=System.in.read();

   bos.write(ch);

  }while((char)ch != '*');

  bos.flush();

  bos.close();

  BufferedInputStream bis=new BufferedInputStream(new FileInputStream(f));

  fsize=bis.available();

  System.out.println("\n Contents of file : " + f.getName() + "\n");

  while(  (ch = bis.read()) != -1 )

  {

   System.out.print((char)ch);

  }

  bis.close();

 }

}

Run: java fileiodemo kani.txt

  Hai eni

*

contents of file : kani.txt

hai eni

Filereader:

The filereader class creates a reader that you can use to read the contents of a file.

Filewriter:

Filewriter creates a writer that you can use to write to a file.

/* FileReader & FileWriter  */

import java.io.*;

class fwr

{

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

{

  int c;

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

FileWriter fw=new FileWriter(f,true);

System.out.println("enter the data");

do

{

c=System.in.read();

fw.write(c);

}

while(c!='$');

fw.flush();

FileReader fr=new FileReader(f);

          while( (c=fr.read())!=-1)

          {

            System.out.print( (char)c);

            }

               

fr.close();

}

}

run: java ll kani

read only:

import java.io.*;

class fread

{

public static void main(String s[])throws Exception

{

int c;

//File f=new File(“fwr.java”);

//FileReader r=new FileReader(f);

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

FileReader re;

if(f.exists())

{

      re = new FileReader(f);

       System.out.println(f.getName());

        System.out.println(f.length());

        while( (c=re.read())!=-1)

                System.out.print( (char)c);

                re.close();

}

else

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

}

}

run: fread fwr.java

getchars() à to extract a string

string  s=”anu”

Sy4ntax:str-var-name.getChars(int start,int end,char[ ] where,int target-start);

s.getchars(1,2,a,5);

import java.io.*;

class fwrite1

{

public static void main(String st[])throws Exception

{

int i;

FileWriter wr=new FileWriter(st[0],true);

String s = "Welcome this is File Writer Program";

char a[] = new char[50];

s.getChars(0,s.length(),a,0);

for( i=0;i<a.length;i++)

        wr.write(a[i]);

wr.close();

FileReader re=new FileReader(st[0]);

while( (i=re.read())!=-1)

        System.out.print( (char)i);

re.close();

}

}

run: java fwrite1  anu

welcome

type anu

welcom