BINARY I/O - Introduction to Java Programming: Comprehensive Version - page 681

java.io.InputStream

+ read(): int

Reads the next byte of data from the input stream. The value byte is returned as
an int value in the range 0 to 255 . If no byte is available because the end of
the stream has been reached, the value -1 is returned.
Reads up to b.length bytes into array b from the input stream and returns the
actual number of bytes read. Returns -1 at the end of the stream.
Reads bytes from the input stream and stores them in b[off], b[off+1], . . .,
b[off+len-1] . The actual number of bytes read is returned. Returns -1
at the end of the stream.
Returns an estimate of the number of bytes that can be read from the input stream.
Closes this input stream and releases any system resources occupied by it.
Skips over and discards n bytes of data from this input stream. The actual
number of bytes skipped is returned.
Tests whether this input stream supports the mark and reset methods.
Marks the current position in this input stream.
Repositions this stream to the position at the time the mark method was last
called on this input stream.

+read(b: byte[]): int

+read(b: byte[], off: int,
len: int): int

+available(): int
+close(): void
+skip(n: long): long

+markSupported(): boolean
+mark(readlimit: int): void
+reset(): void

F IGURE 17.4

The abstract InputStream class defines the methods for the input stream of bytes.

binary input classes, and OutputStream is the root for binary output classes. Figures 17.4
and 17.5 list all the methods in the classes InputStream and OutputStream .

Note
All the methods in the binary I/O classes are declared to throw java.io.IOException
or a subclass of java.io.IOException .

throws IOException

java.io.OutputStream

+ write ( int b ) : void

Writes the specified byte to this output stream. The parameter b is an int value.
(byte)b is written to the output stream.

+write(b: byte[]): void

Writes all the bytes in array b to the output stream.

+write(b: byte[], off: int,
len: int): void

Writes b[off], b[off+1],. . ., b[off+len-1] into the output stream.

+close(): void
+flush(): void

Closes this output stream and releases any system resources occupied by it.
Flushes this output stream and forces any buffered output bytes to be written out.

F IGURE 17.5

The abstract OutputStream class defines the methods for the output stream of bytes.

17.4.1 FileInputStream / FileOutputStream
FileInputStream / FileOutputStream is for reading/writing bytes from/to files.
All the methods in these classes are inherited from InputStream and OutputStream .
FileInputStream / FileOutputStream does not introduce new methods. To construct a
FileInputStream , use the constructors shown in Figure 17.6.
A java.io.FileNotFoundException will occur if you attempt to create a
FileInputStream with a nonexistent file.
To construct a FileOutputStream , use the constructors shown in Figure 17.7.
If the file does not exist, a new file will be created. If the file already exists, the first two
constructors will delete the current content of the file. To retain the current content and append
new data into the file, use the last two constructors and pass true to the append parameter.

FileNotFoundException