java.io.ByteArrayOutputStream
ByteArrayOutputStream
contains an internal buffer that accumulates all the
bytes written to the stream since its creation or the most recent call to the reset
method. At any point, the bytes written to the stream so far may be retrieved in the
form of an array of bytes or a String
. The bytes written so far may also be copied
to some other output stream. The size
method returns the number of characters
written so far.
public classByteArrayOutputStream
extends OutputStream { protected byte[]buf
; protected intcount
; publicByteArrayOutputStream
(); publicByteArrayOutputStream
(int size); public voidwrite
(int b); public voidwrite
(byte[] b, int off, int len) throws NullPointerException, IndexOutOfBoundsException; public intsize
(); public voidreset
(); public byte[]toByteArray
(); public StringtoString
(); public StringtoString
(int hibyte); public voidwriteTo
(OutputStream out) throws IOException; }
22.18.1 protected byte[]
buf
;
An internal array of bytes. Elements buf[0]
through buf[count-1]
are the bytes
that have been written to the stream since its creation or the last reset
(§22.18.8)
operation.
22.18.2 protected int
count
;
This value should always be nonnegative. It is the number of bytes that have been
written to the stream since its creation or the last reset
(§22.18.8) operation.
22.18.3 public
ByteArrayOutputStream
()
This constructor initializes a newly created ByteArrayOutputStream
so that its
internal buffer array has length 32.
22.18.4 public
ByteArrayOutputStream
(int size)
This constructor initializes a newly created ByteArrayOutputStream
so that its
internal buffer array has length size
. This matters only for reasons of efficiency;
the buffer array is replaced by a larger one whenever necessary to accommodate
additional bytes written to the stream.
22.18.5 public void
write
(int b)
One byte is added on the internal buffer. The byte to be added is the eight low-
order bits of the argument n
. The 24 high-order bits of n
are ignored.
Implements the write
method of OutputStream
(§22.15.1).
22.18.6 public void
write
(byte[] b, int off, int len)
throws NullPointerException, IndexOutOfBoundsException
Elements b[off]
through b[off+len-1]
are appended to the internal buffer.
If b
is null
, a NullPointerException
is thrown.
If off
is negative, or len
is negative, or off+len
is greater than the length of the array b
, then an IndexOutOfBoundsException
is thrown.
Overrides the write
method of OutputStream
(§22.15.3).
22.18.7 public int
size
()
The current value of count
is returned.
22.18.8 public void
reset
()
The internal variable count
is reset to zero, thereby logically discarding all bytes
written to the stream so far. However, the internal buffer array, which may be quite
large, remains as it is.
22.18.9 public byte[]
toByteArray
()
A new array of bytes is created and returned. Its length is equal to the current
value of count
. Its initial contents are copies of the bytes written to the stream so
far-that is, elements 0
through count-1
of buf
.
22.18.10 public String
toString
()
A new String
is created and returned. Its length is equal to the current value of
count
. Its initial contents are copies of the bytes written to the stream so far-that
is, elements 0
through count-1
of buf
, zero-extended to produce characters.
Thus, tostring()
has the same effect as toString(0)
(§22.18.11).
Overrides the toString
method of Object
(§20.1.2).
22.18.11 public String
toString
(int hibyte)
A new array of bytes is created and returned. Its length is equal to the current
value of count
. Its initial contents are copies of the bytes written to the stream so
far-that is, elements 0
through count-1
of buf
-with hibyte
supplying the
high-order eight bits of each character. Thus, character k
of the result is equal to:
((hibyte & 0xff) << 8) | (buf[k] & 0xff)See the
String
constructor that accepts a hibyte
argument (§20.12.6).22.18.12 public void
writeTo
(OutputStream out) throws IOException
The current contents of the internal buffer are written to the output stream out
by
the call:
out.write(buf, 0, count)Note that if
out
is the same as this
, the effect is simply to append to the buffer a copy of its current contents, thereby doubling the number of buffered bytes. This may not be a particularly useful effect; the point is merely that the operation does terminate, having had a sensible effect, rather than running off into an endless loop.
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Java Language Specification (HTML generated by Suzette Pelouch on February 24, 1998)
Copyright © 1996 Sun Microsystems, Inc.
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