Binary IO

FileInputStream

• 2 Constructors
  • public FileInputStream ( String filename)
  • public FileInputStream ( File file)

FileOutputStream

• 4 Constructors
  • public FileOutputStream ( String filename)
  • public FileOutputStream ( File file)
  • public FileOutputStream ( String filename, Boolean append)
  • public FileOutputStream ( File file, Boolean append)

DataInputStream

• Constructor
  public DataInputStream ( InputStream instream)
• Example:
  DataInputStream infile = new DataInputStream ( new FileInputStream ( "in.dat" ) ) ;
  infile.readBoolean ( ) ;
  infile.readByte ( ) ;
  infile.readBytes ( ) ;    // Read lower byte of characters
  infile.readChar ( ) ;
  infile.readChars ( ) ;    // Read every character
  infile.readFloat ( ) ;
  infile.readDouble ( ) ;
  infile.readInt ( ) ;
  ...

DataOutputStream

• Constructor
  public DataOutputStream ( OutputStream outstream)
• Example:
  DataOutputStream outfile = new DataOutputStream ( new FileOutputStream ( "out.dat" ) ) ;
  outfile.writeBoolean ( boolTmp) ;
  outfile.writeByte ( intTmp) ;
  outfile.writeBytes ( strTmp) ;    // Write lower byte of characters
  outfile.writeChar ( charTmp) ;
  outfile.writeChars ( strTmp) ;    // Write every character
  outfile.writeFloat ( floatTmp) ;
  outfile.writeDouble ( dblTmp) ;
  outfile.writeInt ( intTmp) ;
  ...

BufferedInputStream/ BufferedOutputStream

• Using buffers to speed up I/O
• Constructor
  public BufferedInputStream ( InputStream in)
  public BufferedInputStream ( InputStream in, int bufferSize)
• Constructor
  public BufferedOutputStream ( OutputStream out)
  public BufferedOutputStream ( OutputStreamr out, int bufferSize)

ObjectInputStream/ ObjectOutputStream

• Enables to perform I/O for objects
• Constructor
  public ObjectInputStream ( InputStream in)
• Constructor
  public ObjectOutputStream ( OutputStream out)

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RandomAccessFile

• to allow a file to be read from and write to at random locations
• Constructor
  // Allow read and write
  RandomAccessFile raf = new RandomAccessFile ( "test.dat" , "rw" ) ;
  // Read only
  RandomAccessFile raf = new RandomAccessFile ( "test.dat" , "r" ) ;
• Example
  RandomAccessFile inout = new RandomAccessFile ( "test.dat" , "rw" ) ;
  
  // Clear the file to destroy the old contents if exists
  inout.setLength ( 0 ) ;
  // Write new integers to the file
  for ( int i = 0 ; i < 200 ; i++ )
      inout.writeInt ( i) ;
  System .out .println ( inout.length ( ) ) ; // length of the file
  inout.seek ( 0 ) ; // Move the file pointer to the beginning
  System .out .println ( inout.readInt ( ) ) ;
  inout.seek ( 1 * 4 ) ; // Move the file pointer to the 2nd number
  System .out .println ( inout.readInt ( ) ) ;
  // Close file
  inout.close ( ) ;