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File IO in Java

       Prof. AshishSingh Bhatia, ast.bhatia@gmail.com,
     ashish@asbspace.in, Web: asbspace.in, M:9879009551


                                 September 21, 2012




Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   1
AGENDA
Overview of IO Classes
OutputStream of IO
InputStream of IO
Writer of IO
Reader of IO
Methods of OutputStream Class
Methods of Writer Class
Methods of Writer Class Extra
Methods of InputStream Class
Methods of Reader Class
InputStream Usage
OutputStream Usage
Bridge Classes
OutputStreamWriter
InputStream Reader
FileInput and FileOutput Stream
  Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   2
Overview of IO Classes




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   3
OutputStream of IO




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   4
InputStream of IO




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   5
Writer of IO




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   6
Reader of IO




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   7
Methods of OutputStream Class

       public void write(int b)
       Writes a single byte to an output stream. Why we need int as
       argument?




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   8
Methods of OutputStream Class

       public void write(int b)
       Writes a single byte to an output stream. Why we need int as
       argument?
       public void write(byte[] b)
       Writes complete byte array in to an outputstream.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   9
Methods of OutputStream Class

       public void write(int b)
       Writes a single byte to an output stream. Why we need int as
       argument?
       public void write(byte[] b)
       Writes complete byte array in to an outputstream.
       public void write(byte[] b, int offset, int len)
       Write a subrange from offset to specified length[number of
       bytes].




    Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   10
Methods of OutputStream Class

       public void write(int b)
       Writes a single byte to an output stream. Why we need int as
       argument?
       public void write(byte[] b)
       Writes complete byte array in to an outputstream.
       public void write(byte[] b, int offset, int len)
       Write a subrange from offset to specified length[number of
       bytes].
       public void flush()
       Flushes the output buffer. Ensures the contents are written to
       the destination.




    Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   11
Methods of OutputStream Class

       public void write(int b)
       Writes a single byte to an output stream. Why we need int as
       argument?
       public void write(byte[] b)
       Writes complete byte array in to an outputstream.
       public void write(byte[] b, int offset, int len)
       Write a subrange from offset to specified length[number of
       bytes].
       public void flush()
       Flushes the output buffer. Ensures the contents are written to
       the destination.
       public void close()
       Closes the outputstream. Further write will generate
       IOException
    Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   12
Methods of Writer Class


        public void write(int ch)
        Writes a single character to an output stream. Why we need
        int as argument?




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   13
Methods of Writer Class


        public void write(int ch)
        Writes a single character to an output stream. Why we need
        int as argument?
        public void write(char[] ch)
        Writes complete character array in to an outputstream.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   14
Methods of Writer Class


        public void write(int ch)
        Writes a single character to an output stream. Why we need
        int as argument?
        public void write(char[] ch)
        Writes complete character array in to an outputstream.
        public void write(char[] b, int offset, int len)
        Write a subrange from offset to specified length[number of
        character].




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   15
Methods of Writer Class


        public void write(int ch)
        Writes a single character to an output stream. Why we need
        int as argument?
        public void write(char[] ch)
        Writes complete character array in to an outputstream.
        public void write(char[] b, int offset, int len)
        Write a subrange from offset to specified length[number of
        character].
        public void flush()
        Flushes the output buffer. Ensures the contents are written to
        the destination.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   16
Methods of Writer Class


        public void write(int ch)
        Writes a single character to an output stream. Why we need
        int as argument?
        public void write(char[] ch)
        Writes complete character array in to an outputstream.
        public void write(char[] b, int offset, int len)
        Write a subrange from offset to specified length[number of
        character].
        public void flush()
        Flushes the output buffer. Ensures the contents are written to
        the destination.
        public void close()
        Closes the writer. Further write will generate IOException

     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   17
Methods of Writer Class Extra




        String is a sequence of Character.
        public void write(String s)




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   18
Methods of Writer Class Extra




        String is a sequence of Character.
        public void write(String s)
        public void write(String s, int offset, int len)




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   19
Methods of Writer Class Extra




        String is a sequence of Character.
        public void write(String s)
        public void write(String s, int offset, int len)
        public void append(char ch)




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   20
Methods of Writer Class Extra




        String is a sequence of Character.
        public void write(String s)
        public void write(String s, int offset, int len)
        public void append(char ch)
        public void append(CharSequence cs)




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   21
Methods of Writer Class Extra




        String is a sequence of Character.
        public void write(String s)
        public void write(String s, int offset, int len)
        public void append(char ch)
        public void append(CharSequence cs)
        public void append(CharSequence cs, int offset,
        int len)




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   22
Methods of InputStream Class
        public int read()
        Read the integer representation of the next available byte of
        input. Returns -1 when the end of file is encountered.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   23
Methods of InputStream Class
        public int read()
        Read the integer representation of the next available byte of
        input. Returns -1 when the end of file is encountered.
        public int read(byte[] b)
        Attempt to read up to b.length bytes in the the b array.
        Returns the number of actual bytes read. -1 is returned when
        the end of file is encountered.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   24
Methods of InputStream Class
        public int read()
        Read the integer representation of the next available byte of
        input. Returns -1 when the end of file is encountered.
        public int read(byte[] b)
        Attempt to read up to b.length bytes in the the b array.
        Returns the number of actual bytes read. -1 is returned when
        the end of file is encountered.
        public int read(byte[] b, int offset, int len)




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   25
Methods of InputStream Class
        public int read()
        Read the integer representation of the next available byte of
        input. Returns -1 when the end of file is encountered.
        public int read(byte[] b)
        Attempt to read up to b.length bytes in the the b array.
        Returns the number of actual bytes read. -1 is returned when
        the end of file is encountered.
        public int read(byte[] b, int offset, int len)
        public long skip(long count)
        count indicates number of bytes to be skipped and return the
        number of byte skipped or -1 in case of end of file.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   26
Methods of InputStream Class
        public int read()
        Read the integer representation of the next available byte of
        input. Returns -1 when the end of file is encountered.
        public int read(byte[] b)
        Attempt to read up to b.length bytes in the the b array.
        Returns the number of actual bytes read. -1 is returned when
        the end of file is encountered.
        public int read(byte[] b, int offset, int len)
        public long skip(long count)
        count indicates number of bytes to be skipped and return the
        number of byte skipped or -1 in case of end of file.
        public int available()
        Number of bytes available for reading.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   27
Methods of InputStream Class
        public int read()
        Read the integer representation of the next available byte of
        input. Returns -1 when the end of file is encountered.
        public int read(byte[] b)
        Attempt to read up to b.length bytes in the the b array.
        Returns the number of actual bytes read. -1 is returned when
        the end of file is encountered.
        public int read(byte[] b, int offset, int len)
        public long skip(long count)
        count indicates number of bytes to be skipped and return the
        number of byte skipped or -1 in case of end of file.
        public int available()
        Number of bytes available for reading.
        public void mark(int readlimit)



     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   28
Methods of InputStream Class
        public int read()
        Read the integer representation of the next available byte of
        input. Returns -1 when the end of file is encountered.
        public int read(byte[] b)
        Attempt to read up to b.length bytes in the the b array.
        Returns the number of actual bytes read. -1 is returned when
        the end of file is encountered.
        public int read(byte[] b, int offset, int len)
        public long skip(long count)
        count indicates number of bytes to be skipped and return the
        number of byte skipped or -1 in case of end of file.
        public int available()
        Number of bytes available for reading.
        public void mark(int readlimit)
        public void reset()

     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   29
Methods of InputStream Class
        public int read()
        Read the integer representation of the next available byte of
        input. Returns -1 when the end of file is encountered.
        public int read(byte[] b)
        Attempt to read up to b.length bytes in the the b array.
        Returns the number of actual bytes read. -1 is returned when
        the end of file is encountered.
        public int read(byte[] b, int offset, int len)
        public long skip(long count)
        count indicates number of bytes to be skipped and return the
        number of byte skipped or -1 in case of end of file.
        public int available()
        Number of bytes available for reading.
        public void mark(int readlimit)
        public void reset()
        public boolean markSupported()
     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   30
Methods of InputStream Class
        public int read()
        Read the integer representation of the next available byte of
        input. Returns -1 when the end of file is encountered.
        public int read(byte[] b)
        Attempt to read up to b.length bytes in the the b array.
        Returns the number of actual bytes read. -1 is returned when
        the end of file is encountered.
        public int read(byte[] b, int offset, int len)
        public long skip(long count)
        count indicates number of bytes to be skipped and return the
        number of byte skipped or -1 in case of end of file.
        public int available()
        Number of bytes available for reading.
        public void mark(int readlimit)
        public void reset()
        public boolean markSupported()
        public void close()
     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 31
Methods of Reader Class



        public int read()




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   32
Methods of Reader Class



        public int read()
        public int read(char[] b)




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   33
Methods of Reader Class



        public int read()
        public int read(char[] b)
        public int read(char[] b, int offset, int len)




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   34
Methods of Reader Class



        public int read()
        public int read(char[] b)
        public int read(char[] b, int offset, int len)
        public long skip(long count)




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   35
Methods of Reader Class



        public int read()
        public int read(char[] b)
        public int read(char[] b, int offset, int len)
        public long skip(long count)
        public boolean ready()




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   36
Methods of Reader Class



        public int read()
        public int read(char[] b)
        public int read(char[] b, int offset, int len)
        public long skip(long count)
        public boolean ready()
        public void mark(int readlimit)




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   37
Methods of Reader Class



        public int read()
        public int read(char[] b)
        public int read(char[] b, int offset, int len)
        public long skip(long count)
        public boolean ready()
        public void mark(int readlimit)
        public void reset()




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   38
Methods of Reader Class



        public int read()
        public int read(char[] b)
        public int read(char[] b, int offset, int len)
        public long skip(long count)
        public boolean ready()
        public void mark(int readlimit)
        public void reset()
        public boolean markSupported()




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   39
Methods of Reader Class



        public int read()
        public int read(char[] b)
        public int read(char[] b, int offset, int len)
        public long skip(long count)
        public boolean ready()
        public void mark(int readlimit)
        public void reset()
        public boolean markSupported()
        public void close()




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   40
InputStream Usage




    Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   41
OutputStream Usage




    Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   42
Bridge Classes



        OutputStreamWriter and InputStreamReader
        Character Base Stream Classes which inturns work on bytes.
        Handles unicode character and bytes both.
        Encoding and Decoding of unicode character from and to
        various character set.
        java.nio.charset package has classes which handle
        encoding and decoding.
        class Charset represents different character set.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   43
OutputStreamWriter




    Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   44
InputStream Reader




    Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   45
FileInput and FileOutput Stream




        Output and input of binary files.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   46
FileInput and FileOutput Stream




        Output and input of binary files.
        FileOutputStream create and write bytes in to physical file.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   47
FileInput and FileOutput Stream




        Output and input of binary files.
        FileOutputStream create and write bytes in to physical file.
        If file exists it overwrites it until append flag is used.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   48
FileInput and FileOutput Stream




        Output and input of binary files.
        FileOutputStream create and write bytes in to physical file.
        If file exists it overwrites it until append flag is used.
        Inherits all the methods from the OutputStream.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   49
FileInput and FileOutput Stream




        Output and input of binary files.
        FileOutputStream create and write bytes in to physical file.
        If file exists it overwrites it until append flag is used.
        Inherits all the methods from the OutputStream.
        Additional methods are
        public FileDescriptor getFD()
        public FileChannel getChannel()




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   50
FileDescriptor




        Whenever any file is opened for input or output, it uses a file
        descriptor.




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   51
FileDescriptor




        Whenever any file is opened for input or output, it uses a file
        descriptor.
        0=Standard Input




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   52
FileDescriptor




        Whenever any file is opened for input or output, it uses a file
        descriptor.
        0=Standard Input
        1=Standard Output




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   53
FileDescriptor




        Whenever any file is opened for input or output, it uses a file
        descriptor.
        0=Standard Input
        1=Standard Output
        2=Standard Error




     Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551   54

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Java I/O Part 2

  • 1. File IO in Java Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 September 21, 2012 Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 1
  • 2. AGENDA Overview of IO Classes OutputStream of IO InputStream of IO Writer of IO Reader of IO Methods of OutputStream Class Methods of Writer Class Methods of Writer Class Extra Methods of InputStream Class Methods of Reader Class InputStream Usage OutputStream Usage Bridge Classes OutputStreamWriter InputStream Reader FileInput and FileOutput Stream Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 2
  • 3. Overview of IO Classes Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 3
  • 4. OutputStream of IO Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 4
  • 5. InputStream of IO Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 5
  • 6. Writer of IO Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 6
  • 7. Reader of IO Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 7
  • 8. Methods of OutputStream Class public void write(int b) Writes a single byte to an output stream. Why we need int as argument? Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 8
  • 9. Methods of OutputStream Class public void write(int b) Writes a single byte to an output stream. Why we need int as argument? public void write(byte[] b) Writes complete byte array in to an outputstream. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 9
  • 10. Methods of OutputStream Class public void write(int b) Writes a single byte to an output stream. Why we need int as argument? public void write(byte[] b) Writes complete byte array in to an outputstream. public void write(byte[] b, int offset, int len) Write a subrange from offset to specified length[number of bytes]. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 10
  • 11. Methods of OutputStream Class public void write(int b) Writes a single byte to an output stream. Why we need int as argument? public void write(byte[] b) Writes complete byte array in to an outputstream. public void write(byte[] b, int offset, int len) Write a subrange from offset to specified length[number of bytes]. public void flush() Flushes the output buffer. Ensures the contents are written to the destination. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 11
  • 12. Methods of OutputStream Class public void write(int b) Writes a single byte to an output stream. Why we need int as argument? public void write(byte[] b) Writes complete byte array in to an outputstream. public void write(byte[] b, int offset, int len) Write a subrange from offset to specified length[number of bytes]. public void flush() Flushes the output buffer. Ensures the contents are written to the destination. public void close() Closes the outputstream. Further write will generate IOException Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 12
  • 13. Methods of Writer Class public void write(int ch) Writes a single character to an output stream. Why we need int as argument? Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 13
  • 14. Methods of Writer Class public void write(int ch) Writes a single character to an output stream. Why we need int as argument? public void write(char[] ch) Writes complete character array in to an outputstream. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 14
  • 15. Methods of Writer Class public void write(int ch) Writes a single character to an output stream. Why we need int as argument? public void write(char[] ch) Writes complete character array in to an outputstream. public void write(char[] b, int offset, int len) Write a subrange from offset to specified length[number of character]. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 15
  • 16. Methods of Writer Class public void write(int ch) Writes a single character to an output stream. Why we need int as argument? public void write(char[] ch) Writes complete character array in to an outputstream. public void write(char[] b, int offset, int len) Write a subrange from offset to specified length[number of character]. public void flush() Flushes the output buffer. Ensures the contents are written to the destination. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 16
  • 17. Methods of Writer Class public void write(int ch) Writes a single character to an output stream. Why we need int as argument? public void write(char[] ch) Writes complete character array in to an outputstream. public void write(char[] b, int offset, int len) Write a subrange from offset to specified length[number of character]. public void flush() Flushes the output buffer. Ensures the contents are written to the destination. public void close() Closes the writer. Further write will generate IOException Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 17
  • 18. Methods of Writer Class Extra String is a sequence of Character. public void write(String s) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 18
  • 19. Methods of Writer Class Extra String is a sequence of Character. public void write(String s) public void write(String s, int offset, int len) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 19
  • 20. Methods of Writer Class Extra String is a sequence of Character. public void write(String s) public void write(String s, int offset, int len) public void append(char ch) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 20
  • 21. Methods of Writer Class Extra String is a sequence of Character. public void write(String s) public void write(String s, int offset, int len) public void append(char ch) public void append(CharSequence cs) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 21
  • 22. Methods of Writer Class Extra String is a sequence of Character. public void write(String s) public void write(String s, int offset, int len) public void append(char ch) public void append(CharSequence cs) public void append(CharSequence cs, int offset, int len) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 22
  • 23. Methods of InputStream Class public int read() Read the integer representation of the next available byte of input. Returns -1 when the end of file is encountered. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 23
  • 24. Methods of InputStream Class public int read() Read the integer representation of the next available byte of input. Returns -1 when the end of file is encountered. public int read(byte[] b) Attempt to read up to b.length bytes in the the b array. Returns the number of actual bytes read. -1 is returned when the end of file is encountered. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 24
  • 25. Methods of InputStream Class public int read() Read the integer representation of the next available byte of input. Returns -1 when the end of file is encountered. public int read(byte[] b) Attempt to read up to b.length bytes in the the b array. Returns the number of actual bytes read. -1 is returned when the end of file is encountered. public int read(byte[] b, int offset, int len) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 25
  • 26. Methods of InputStream Class public int read() Read the integer representation of the next available byte of input. Returns -1 when the end of file is encountered. public int read(byte[] b) Attempt to read up to b.length bytes in the the b array. Returns the number of actual bytes read. -1 is returned when the end of file is encountered. public int read(byte[] b, int offset, int len) public long skip(long count) count indicates number of bytes to be skipped and return the number of byte skipped or -1 in case of end of file. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 26
  • 27. Methods of InputStream Class public int read() Read the integer representation of the next available byte of input. Returns -1 when the end of file is encountered. public int read(byte[] b) Attempt to read up to b.length bytes in the the b array. Returns the number of actual bytes read. -1 is returned when the end of file is encountered. public int read(byte[] b, int offset, int len) public long skip(long count) count indicates number of bytes to be skipped and return the number of byte skipped or -1 in case of end of file. public int available() Number of bytes available for reading. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 27
  • 28. Methods of InputStream Class public int read() Read the integer representation of the next available byte of input. Returns -1 when the end of file is encountered. public int read(byte[] b) Attempt to read up to b.length bytes in the the b array. Returns the number of actual bytes read. -1 is returned when the end of file is encountered. public int read(byte[] b, int offset, int len) public long skip(long count) count indicates number of bytes to be skipped and return the number of byte skipped or -1 in case of end of file. public int available() Number of bytes available for reading. public void mark(int readlimit) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 28
  • 29. Methods of InputStream Class public int read() Read the integer representation of the next available byte of input. Returns -1 when the end of file is encountered. public int read(byte[] b) Attempt to read up to b.length bytes in the the b array. Returns the number of actual bytes read. -1 is returned when the end of file is encountered. public int read(byte[] b, int offset, int len) public long skip(long count) count indicates number of bytes to be skipped and return the number of byte skipped or -1 in case of end of file. public int available() Number of bytes available for reading. public void mark(int readlimit) public void reset() Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 29
  • 30. Methods of InputStream Class public int read() Read the integer representation of the next available byte of input. Returns -1 when the end of file is encountered. public int read(byte[] b) Attempt to read up to b.length bytes in the the b array. Returns the number of actual bytes read. -1 is returned when the end of file is encountered. public int read(byte[] b, int offset, int len) public long skip(long count) count indicates number of bytes to be skipped and return the number of byte skipped or -1 in case of end of file. public int available() Number of bytes available for reading. public void mark(int readlimit) public void reset() public boolean markSupported() Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 30
  • 31. Methods of InputStream Class public int read() Read the integer representation of the next available byte of input. Returns -1 when the end of file is encountered. public int read(byte[] b) Attempt to read up to b.length bytes in the the b array. Returns the number of actual bytes read. -1 is returned when the end of file is encountered. public int read(byte[] b, int offset, int len) public long skip(long count) count indicates number of bytes to be skipped and return the number of byte skipped or -1 in case of end of file. public int available() Number of bytes available for reading. public void mark(int readlimit) public void reset() public boolean markSupported() public void close() Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 31
  • 32. Methods of Reader Class public int read() Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 32
  • 33. Methods of Reader Class public int read() public int read(char[] b) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 33
  • 34. Methods of Reader Class public int read() public int read(char[] b) public int read(char[] b, int offset, int len) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 34
  • 35. Methods of Reader Class public int read() public int read(char[] b) public int read(char[] b, int offset, int len) public long skip(long count) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 35
  • 36. Methods of Reader Class public int read() public int read(char[] b) public int read(char[] b, int offset, int len) public long skip(long count) public boolean ready() Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 36
  • 37. Methods of Reader Class public int read() public int read(char[] b) public int read(char[] b, int offset, int len) public long skip(long count) public boolean ready() public void mark(int readlimit) Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 37
  • 38. Methods of Reader Class public int read() public int read(char[] b) public int read(char[] b, int offset, int len) public long skip(long count) public boolean ready() public void mark(int readlimit) public void reset() Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 38
  • 39. Methods of Reader Class public int read() public int read(char[] b) public int read(char[] b, int offset, int len) public long skip(long count) public boolean ready() public void mark(int readlimit) public void reset() public boolean markSupported() Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 39
  • 40. Methods of Reader Class public int read() public int read(char[] b) public int read(char[] b, int offset, int len) public long skip(long count) public boolean ready() public void mark(int readlimit) public void reset() public boolean markSupported() public void close() Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 40
  • 41. InputStream Usage Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 41
  • 42. OutputStream Usage Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 42
  • 43. Bridge Classes OutputStreamWriter and InputStreamReader Character Base Stream Classes which inturns work on bytes. Handles unicode character and bytes both. Encoding and Decoding of unicode character from and to various character set. java.nio.charset package has classes which handle encoding and decoding. class Charset represents different character set. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 43
  • 44. OutputStreamWriter Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 44
  • 45. InputStream Reader Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 45
  • 46. FileInput and FileOutput Stream Output and input of binary files. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 46
  • 47. FileInput and FileOutput Stream Output and input of binary files. FileOutputStream create and write bytes in to physical file. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 47
  • 48. FileInput and FileOutput Stream Output and input of binary files. FileOutputStream create and write bytes in to physical file. If file exists it overwrites it until append flag is used. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 48
  • 49. FileInput and FileOutput Stream Output and input of binary files. FileOutputStream create and write bytes in to physical file. If file exists it overwrites it until append flag is used. Inherits all the methods from the OutputStream. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 49
  • 50. FileInput and FileOutput Stream Output and input of binary files. FileOutputStream create and write bytes in to physical file. If file exists it overwrites it until append flag is used. Inherits all the methods from the OutputStream. Additional methods are public FileDescriptor getFD() public FileChannel getChannel() Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 50
  • 51. FileDescriptor Whenever any file is opened for input or output, it uses a file descriptor. Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 51
  • 52. FileDescriptor Whenever any file is opened for input or output, it uses a file descriptor. 0=Standard Input Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 52
  • 53. FileDescriptor Whenever any file is opened for input or output, it uses a file descriptor. 0=Standard Input 1=Standard Output Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 53
  • 54. FileDescriptor Whenever any file is opened for input or output, it uses a file descriptor. 0=Standard Input 1=Standard Output 2=Standard Error Prof. AshishSingh Bhatia, ast.bhatia@gmail.com, ashish@asbspace.in, Web: asbspace.in, M:9879009551 54