Class ByteArrayOutputStream
- java.lang.Object
-
- java.io.OutputStream
-
- java.io.ByteArrayOutputStream
- All Implemented Interfaces:
-
Closeable
,Flushable
,AutoCloseable
public class ByteArrayOutputStream extends OutputStream
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
Field Summary
Modifier and Type | Field | Description |
---|---|---|
protected byte[] | buf | The buffer where data is stored. |
protected int | count | The number of valid bytes in the buffer. |
Constructor Summary
Constructor | Description |
---|---|
ByteArrayOutputStream() | Creates a new |
ByteArrayOutputStream(int size) | Creates a new |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
void | close() | Closing a |
void | reset() | Resets the |
int | size() | Returns the current size of the buffer. |
byte[] | toByteArray() | Creates a newly allocated byte array. |
String | toString() | Converts the buffer's contents into a string decoding bytes using the platform's default character set. |
String | toString(int hibyte) | Deprecated. This method does not properly convert bytes into characters. |
String | toString(String charsetName) | Converts the buffer's contents into a string by decoding the bytes using the named |
String | toString(Charset charset) | Converts the buffer's contents into a string by decoding the bytes using the specified |
void | write(byte[] b,
int off,
int len) | Writes |
void | write(int b) | Writes the specified byte to this |
void | writeBytes(byte[] b) | Writes the complete contents of the specified byte array to this |
void | writeTo(OutputStream out) | Writes the complete contents of this |
Methods declared in class java.io.OutputStream
flush, nullOutputStream, write
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait
Field Detail
buf
protected byte[] buf
The buffer where data is stored.
count
protected int count
The number of valid bytes in the buffer.
Constructor Detail
ByteArrayOutputStream
public ByteArrayOutputStream()
Creates a new ByteArrayOutputStream
. The buffer capacity is initially 32 bytes, though its size increases if necessary.
ByteArrayOutputStream
public ByteArrayOutputStream(int size)
Creates a new ByteArrayOutputStream
, with a buffer capacity of the specified size, in bytes.
- Parameters:
-
size
- the initial size. - Throws:
-
IllegalArgumentException
- if size is negative.
Method Detail
write
public void write(int b)
Writes the specified byte to this ByteArrayOutputStream
.
- Specified by:
-
write
in classOutputStream
- Parameters:
-
b
- the byte to be written.
write
public void write(byte[] b, int off, int len)
Writes len
bytes from the specified byte array starting at offset off
to this ByteArrayOutputStream
.
- 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 this ByteArrayOutputStream
.
- API Note:
- This method is equivalent to
write(b, 0, b.length)
. - Parameters:
-
b
- the data. - Throws:
-
NullPointerException
- ifb
isnull
. - Since:
- 11
writeTo
public void writeTo(OutputStream out) throws IOException
Writes the complete contents of this ByteArrayOutputStream
to the specified output stream argument, as if by calling the output stream's write method using out.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 the count
field of this ByteArrayOutputStream
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:
ByteArrayInputStream.count
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()
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:
count
toString
public String toString()
Converts the buffer's contents into a string decoding bytes using the platform's default character set. The length of the new String
is a function of the character set, 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 platform's default character set. The CharsetDecoder class should be used when more control over the decoding process is required.
toString
public String toString(String charsetName) throws UnsupportedEncodingException
Converts the buffer's contents into a string by decoding the bytes using the named charset
.
This method is equivalent to #toString(charset)
that takes a charset
.
An invocation of this method of the form
ByteArrayOutputStream b = ... b.toString("UTF-8")behaves in exactly the same way as the expression
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
public String toString(Charset charset)
Converts the buffer's contents into a string by decoding the bytes using the specified charset
. The length of the new String
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 public String toString(int hibyte)
toString(String charsetName)
or toString(Charset charset)
method, which takes an encoding-name or charset argument, or the toString()
method, which uses the platform's default character encoding.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:
-
size()
,toString(String)
,toString()
close
public void close() throws IOException
Closing a ByteArrayOutputStream
has no effect. The methods in this class can be called after the stream has been closed without generating an IOException
.
- Specified by:
-
close
in interfaceAutoCloseable
- Specified by:
-
close
in interfaceCloseable
- Overrides:
-
close
in classOutputStream
- Throws:
-
IOException
- if an I/O error occurs.