Package java.io

Class ByteArrayOutputStream

java.lang.Object
java.io.OutputStream
java.io.ByteArrayOutputStream
All Implemented Interfaces:
Closeable, Flushable, AutoCloseable
public class ByteArrayOutputStream
extends OutputStream
A specialized OutputStream for class for writing content to an (internal) byte array. As bytes are written to this stream, the byte array may be expanded to hold more bytes. When the writing is considered to be finished, a copy of the byte array can be requested from the class.
See Also:
ByteArrayInputStream

  • Field Summary

    Fields
    Modifier and Type Field Description
    protected byte[] buf
    The byte array containing the bytes written.
    protected int count
    The number of bytes written.

  • Constructor Summary

    Constructors
    Constructor Description
    ByteArrayOutputStream()
    Constructs a new ByteArrayOutputStream with a default size of 32 bytes.
    ByteArrayOutputStream​(int size)
    Constructs a new ByteArrayOutputStream with a default size of size bytes.

  • Method Summary

    Modifier and Type Method Description
    void close()
    Closes this stream.
    void reset()
    Resets this stream to the beginning of the underlying byte array.
    int size()
    Returns the total number of bytes written to this stream so far.
    byte[] toByteArray()
    Returns the contents of this ByteArrayOutputStream as a byte array.
    String toString()
    Returns the contents of this ByteArrayOutputStream as a string.
    String toString​(int hibyte)
    Deprecated.
    Use toString() instead.
    String toString​(String charsetName)
    Returns the contents of this ByteArrayOutputStream as a string converted according to the encoding declared in charsetName.
    void write​(byte[] buffer, int offset, int len)
    Writes count bytes from the byte array buffer starting at offset index to this stream.
    void write​(int oneByte)
    Writes the specified byte oneByte to the OutputStream.
    void writeTo​(OutputStream out)
    Takes the contents of this stream and writes it to the output stream out.

    Methods inherited from class java.io.OutputStream

    flush, write

    Methods inherited from class java.lang.Object

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

  • Field Details

    • buf

      protected byte[] buf
      The byte array containing the bytes written.

    • count

      protected int count
      The number of bytes written.

  • Constructor Details

    • ByteArrayOutputStream

      public ByteArrayOutputStream()
      Constructs a new ByteArrayOutputStream with a default size of 32 bytes. If more than 32 bytes are written to this instance, the underlying byte array will expand.

    • ByteArrayOutputStream

      public ByteArrayOutputStream​(int size)
      Constructs a new ByteArrayOutputStream with a default size of size bytes. If more than size bytes are written to this instance, the underlying byte array will expand.
      Parameters:
      size - initial size for the underlying byte array, must be non-negative.
      Throws:
      IllegalArgumentException - if size < 0.

  • Method Details

    • close

      public void close() throws IOException
      Closes this stream. This releases system resources used for this stream.
      Specified by:
      close in interface AutoCloseable
      Specified by:
      close in interface Closeable
      Overrides:
      close in class OutputStream
      Throws:
      IOException - if an error occurs while attempting to close this stream.

    • reset

      public void reset()
      Resets this stream to the beginning of the underlying byte array. All subsequent writes will overwrite any bytes previously stored in this stream.

    • size

      public int size()
      Returns the total number of bytes written to this stream so far.
      Returns:
      the number of bytes written to this stream.

    • toByteArray

      public byte[] toByteArray()
      Returns the contents of this ByteArrayOutputStream as a byte array. Any changes made to the receiver after returning will not be reflected in the byte array returned to the caller.
      Returns:
      this stream's current contents as a byte array.

    • toString

      public String toString()
      Returns the contents of this ByteArrayOutputStream as a string. Any changes made to the receiver after returning will not be reflected in the string returned to the caller.
      Overrides:
      toString in class Object
      Returns:
      this stream's current contents as a string.

    • toString

      @Deprecated public String toString​(int hibyte)
      Deprecated.
      Use toString() instead.
      Returns the contents of this ByteArrayOutputStream as a string. Each byte b in this stream is converted to a character c using the following function: c == (char)(((hibyte & 0xff) << 8) | (b & 0xff)). This method is deprecated and either toString() or toString(String) should be used.
      Parameters:
      hibyte - the high byte of each resulting Unicode character.
      Returns:
      this stream's current contents as a string with the high byte set to hibyte.

    • toString

      public String toString​(String charsetName) throws UnsupportedEncodingException
      Returns the contents of this ByteArrayOutputStream as a string converted according to the encoding declared in charsetName.
      Parameters:
      charsetName - a string representing the encoding to use when translating this stream to a string.
      Returns:
      this stream's current contents as an encoded string.
      Throws:
      UnsupportedEncodingException - if the provided encoding is not supported.

    • write

      public void write​(byte[] buffer, int offset, int len)
      Writes count bytes from the byte array buffer starting at offset index to this stream.
      Overrides:
      write in class OutputStream
      Parameters:
      buffer - the buffer to be written.
      offset - the initial position in buffer to retrieve bytes.
      len - the number of bytes of buffer to write.
      Throws:
      NullPointerException - if buffer is null.
      IndexOutOfBoundsException - if offset < 0 or len < 0, or if offset + len is greater than the length of buffer.

    • write

      public void write​(int oneByte)
      Writes the specified byte oneByte to the OutputStream. Only the low order byte of oneByte is written.
      Specified by:
      write in class OutputStream
      Parameters:
      oneByte - the byte to be written.

    • writeTo

      public void writeTo​(OutputStream out) throws IOException
      Takes the contents of this stream and writes it to the output stream out.
      Parameters:
      out - an OutputStream on which to write the contents of this stream.
      Throws:
      IOException - if an error occurs while writing to out.