程序包 java.io

类 ByteArrayOutputStream

java.lang.Object

java.io.OutputStream

java.io.ByteArrayOutputStream

所有已实现的接口:

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.

从以下版本开始:

JDK1.0

字段概要

字段

限定符和类型	字段	说明
protected byte[]	buf	The buffer where data is stored.
protected int	count	The number of valid bytes in the buffer.

构造器概要

构造器

构造器	说明
ByteArrayOutputStream()	Creates a new byte array output stream.
ByteArrayOutputStream(int size)	Creates a new byte array output stream, with a buffer capacity of the specified size, in bytes.

方法概要

限定符和类型	方法	说明
void	close()	Closing a ByteArrayOutputStream has no effect.
void	reset()	Resets the count field of this byte array output stream to zero, so that all currently accumulated output in the output stream is discarded.
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)	已过时。 This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the toString(String enc) method, which takes an encoding-name argument, or the toString() method, which uses the platform's default character encoding.
String	toString(String charsetName)	Converts the buffer's contents into a string by decoding the bytes using the named charset.
void	write(byte[] b, int off, int len)	Writes len bytes from the specified byte array starting at offset off to this byte array output stream.
void	write(int b)	Writes the specified byte to this byte array output stream.
void	writeTo(OutputStream out)	Writes the complete contents of this byte array output stream to the specified output stream argument, as if by calling the output stream's write method using out.write(buf, 0, count).

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

从类继承的方法 java.io.OutputStream

flush, write

字段详细资料

buf

protected byte[] buf

The buffer where data is stored.

count

protected int count

The number of valid bytes in the buffer.

构造器详细资料

ByteArrayOutputStream

public ByteArrayOutputStream()

Creates a new byte array output stream. The buffer capacity is initially 32 bytes, though its size increases if necessary.

ByteArrayOutputStream

public ByteArrayOutputStream(int size)

Creates a new byte array output stream, with a buffer capacity of the specified size, in bytes.

参数:

size - the initial size.

抛出:

IllegalArgumentException - if size is negative.

方法详细资料

write

public void write(int b)

Writes the specified byte to this byte array output stream.

指定者:

write 在类中 OutputStream

参数:

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 byte array output stream.

覆盖:

write 在类中 OutputStream

参数:

b - the data.

off - the start offset in the data.

len - the number of bytes to write.

writeTo

public void writeTo(OutputStream out)
             throws IOException

Writes the complete contents of this byte array output stream to the specified output stream argument, as if by calling the output stream's write method using out.write(buf, 0, count).

参数:

out - the output stream to which to write the data.

抛出:

IOException - if an I/O error occurs.

reset

public void reset()

Resets the count field of this byte array output stream 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.

另请参阅:

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.

返回:

the current contents of this output stream, as a byte array.

另请参阅:

size()

size

public int size()

Returns the current size of the buffer.

返回:

the value of the count field, which is the number of valid bytes in this output stream.

另请参阅:

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.

覆盖:

toString 在类中 Object

返回:

String decoded from the buffer's contents.

从以下版本开始:

JDK1.1

toString

public String toString(String charsetName)
                throws UnsupportedEncodingException

Converts the buffer's contents into a string by decoding the bytes using the named 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 this charset's default replacement string. The CharsetDecoder class should be used when more control over the decoding process is required.

参数:

charsetName - the name of a supported charset

返回:

String decoded from the buffer's contents.

抛出:

UnsupportedEncodingException - If the named charset is not supported

从以下版本开始:

JDK1.1

toString

@Deprecated
public String toString(int hibyte)

已过时。 This method does not properly convert bytes into characters. As of JDK 1.1, the preferred way to do this is via the toString(String enc) method, which takes an encoding-name 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))
 

参数:

hibyte - the high byte of each resulting Unicode character.

返回:

the current contents of the output stream, as a string.

另请参阅:

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.

指定者:

close 在接口中 AutoCloseable

指定者:

close 在接口中 Closeable

覆盖:

close 在类中 OutputStream

抛出:

IOException - if an I/O error occurs.