Class ByteArrayOutputStream
java.lang.Object
java.io.OutputStream
java.io.ByteArrayOutputStream
- All Implemented Interfaces:
Closeable
,Flushable
,AutoCloseable
This class implements an output stream in which the data is
written into a byte array. The buffer automatically grows as data
is written to it.
The data can be retrieved using
toByteArray()
and
toString()
.
Closing a ByteArrayOutputStream
has no effect. The methods in
this class can be called after the stream has been closed without
generating an IOException
.
- Since:
- 1.0
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Field Summary
-
Constructor Summary
ConstructorDescriptionCreates a newByteArrayOutputStream
.ByteArrayOutputStream
(int size) Creates a newByteArrayOutputStream
, with a buffer capacity of the specified size, in bytes. -
Method Summary
Modifier and TypeMethodDescriptionvoid
close()
Closing aByteArrayOutputStream
has no effect.void
reset()
Resets thecount
field of thisByteArrayOutputStream
to zero, so that all currently accumulated output in the output stream is discarded.int
size()
Returns the current size of the buffer.byte[]
Creates a newly allocated byte array.toString()
Converts the buffer's contents into a string decoding bytes using the default charset.toString
(int hibyte) Deprecated.This method does not properly convert bytes into characters.Converts the buffer's contents into a string by decoding the bytes using the namedcharset
.Converts the buffer's contents into a string by decoding the bytes using the specifiedcharset
.void
write
(byte[] b, int off, int len) Writeslen
bytes from the specified byte array starting at offsetoff
to thisByteArrayOutputStream
.void
write
(int b) Writes the specified byte to thisByteArrayOutputStream
.void
writeBytes
(byte[] b) Writes the complete contents of the specified byte array to thisByteArrayOutputStream
.void
writeTo
(OutputStream out) Writes the complete contents of thisByteArrayOutputStream
to the specified output stream argument, as if by calling the output stream's write method usingout.write(buf, 0, count)
.Methods declared in class java.io.OutputStream
flush, nullOutputStream, write
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Field Details
-
buf
protected byte[] bufThe buffer where data is stored. -
count
protected int countThe number of valid bytes in the buffer.
-
-
Constructor Details
-
ByteArrayOutputStream
public ByteArrayOutputStream()Creates a newByteArrayOutputStream
. The buffer capacity is initially 32 bytes, though its size increases if necessary. -
ByteArrayOutputStream
public ByteArrayOutputStream(int size) Creates a newByteArrayOutputStream
, with a buffer capacity of the specified size, in bytes.- Parameters:
size
- the initial size.- Throws:
IllegalArgumentException
- if size is negative.
-
-
Method Details
-
write
public void write(int b) Writes the specified byte to thisByteArrayOutputStream
.- Specified by:
write
in classOutputStream
- Parameters:
b
- the byte to be written.
-
write
public void write(byte[] b, int off, int len) Writeslen
bytes from the specified byte array starting at offsetoff
to thisByteArrayOutputStream
.- Overrides:
write
in classOutputStream
- Parameters:
b
- the data.off
- the start offset in the data.len
- the number of bytes to write.- Throws:
NullPointerException
- ifb
isnull
.IndexOutOfBoundsException
- ifoff
is negative,len
is negative, orlen
is greater thanb.length - off
-
writeBytes
public void writeBytes(byte[] b) Writes the complete contents of the specified byte array to thisByteArrayOutputStream
.- API Note:
- This method is equivalent to
write(b, 0, b.length)
. - Parameters:
b
- the data.- Throws:
NullPointerException
- ifb
isnull
.- Since:
- 11
-
writeTo
Writes the complete contents of thisByteArrayOutputStream
to the specified output stream argument, as if by calling the output stream's write method usingout.write(buf, 0, count)
.- Parameters:
out
- the output stream to which to write the data.- Throws:
NullPointerException
- ifout
isnull
.IOException
- if an I/O error occurs.
-
reset
public void reset()Resets thecount
field of thisByteArrayOutputStream
to zero, so that all currently accumulated output in the output stream is discarded. The output stream can be used again, reusing the already allocated buffer space.- See Also:
-
toByteArray
public byte[] toByteArray()Creates a newly allocated byte array. Its size is the current size of this output stream and the valid contents of the buffer have been copied into it.- Returns:
- the current contents of this output stream, as a byte array.
- See Also:
-
size
public int size()Returns the current size of the buffer.- Returns:
- the value of the
count
field, which is the number of valid bytes in this output stream. - See Also:
-
toString
Converts the buffer's contents into a string decoding bytes using the default charset. The length of the newString
is a function of the charset, and hence may not be equal to the size of the buffer.This method always replaces malformed-input and unmappable-character sequences with the default replacement string for the default charset. The CharsetDecoder class should be used when more control over the decoding process is required.
-
toString
Converts the buffer's contents into a string by decoding the bytes using the namedcharset
.This method is equivalent to
#toString(charset)
that takes acharset
.An invocation of this method of the form
ByteArrayOutputStream b; b.toString("UTF-8")
ByteArrayOutputStream b; b.toString(StandardCharsets.UTF_8)
- Parameters:
charsetName
- the name of a supportedcharset
- Returns:
- String decoded from the buffer's contents.
- Throws:
UnsupportedEncodingException
- If the named charset is not supported- Since:
- 1.1
-
toString
Converts the buffer's contents into a string by decoding the bytes using the specifiedcharset
. The length of the newString
is a function of the charset, and hence may not be equal to the length of the byte array.This method always replaces malformed-input and unmappable-character sequences with the charset's default replacement string. The
CharsetDecoder
class should be used when more control over the decoding process is required.- Parameters:
charset
- the charset to be used to decode thebytes
- Returns:
- String decoded from the buffer's contents.
- Since:
- 10
-
toString
Deprecated.This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via thetoString(String charsetName)
ortoString(Charset charset)
method, which takes an encoding-name or charset argument, or thetoString()
method, which uses the default charset.Creates a newly allocated string. Its size is the current size of the output stream and the valid contents of the buffer have been copied into it. Each character c in the resulting string is constructed from the corresponding element b in the byte array such that:c == (char)(((hibyte & 0xff) << 8) | (b & 0xff))
- Parameters:
hibyte
- the high byte of each resulting Unicode character.- Returns:
- the current contents of the output stream, as a string.
- See Also:
-
close
Closing aByteArrayOutputStream
has no effect. The methods in this class can be called after the stream has been closed without generating anIOException
.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Overrides:
close
in classOutputStream
- Throws:
IOException
- if an I/O error occurs.
-