All Implemented Interfaces:

Closeable, DataOutput, Flushable, AutoCloseable

public class DataOutputStream
extends FilterOutputStream
implements DataOutput

A data output stream lets an application write primitive Java data types to an output stream in a portable way. An application can then use a data input stream to read the data back in.

Since:

1.0

See Also:

DataInputStream

• Field Summary

  Fields 

  Modifier and Type	Field	Description
  protected int	written	The number of bytes written to the data output stream so far.

• Constructor Summary

  Constructors 

  Constructor	Description
  DataOutputStream​(OutputStream out)	Creates a new data output stream to write data to the specified underlying output stream.

• Method Summary

  Modifier and Type	Method	Description
  void	flush()	Flushes this data output stream.
  int	size()	Returns the current value of the counter written, the number of bytes written to this data output stream so far.
  void	write​(byte[] b, int off, int len)	Writes len bytes from the specified byte array starting at offset off to the underlying output stream.
  void	write​(int b)	Writes the specified byte (the low eight bits of the argument b) to the underlying output stream.
  void	writeBoolean​(boolean v)	Writes a boolean to the underlying output stream as a 1-byte value.
  void	writeByte​(int v)	Writes out a byte to the underlying output stream as a 1-byte value.
  void	writeBytes​(String s)	Writes out the string to the underlying output stream as a sequence of bytes.
  void	writeChar​(int v)	Writes a char to the underlying output stream as a 2-byte value, high byte first.
  void	writeChars​(String s)	Writes a string to the underlying output stream as a sequence of characters.
  void	writeDouble​(double v)	Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the underlying output stream as an 8-byte quantity, high byte first.
  void	writeFloat​(float v)	Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the underlying output stream as a 4-byte quantity, high byte first.
  void	writeInt​(int v)	Writes an int to the underlying output stream as four bytes, high byte first.
  void	writeLong​(long v)	Writes a long to the underlying output stream as eight bytes, high byte first.
  void	writeShort​(int v)	Writes a short to the underlying output stream as two bytes, high byte first.
  void	writeUTF​(String str)	Writes a string to the underlying output stream using modified UTF-8 encoding in a machine-independent manner.

  Methods declared in class java.lang.Object

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

• Field Details

  • written

    protected int written

    The number of bytes written to the data output stream so far. If this counter overflows, it will be wrapped to Integer.MAX_VALUE.

• Constructor Details

  • DataOutputStream

    Creates a new data output stream to write data to the specified underlying output stream. The counter written is set to zero.

    Parameters:

    out - the underlying output stream, to be saved for later use.

    See Also:

    FilterOutputStream.out

• Method Details

  • write

    Writes the specified byte (the low eight bits of the argument b) to the underlying output stream. If no exception is thrown, the counter written is incremented by 1.

    Implements the write method of OutputStream.

    Specified by:

    write in interface DataOutput

    Overrides:

    write in class FilterOutputStream

    Parameters:

    b - the byte to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out

  • write

    public void write​(byte[] b, int off, int len) throws IOException

    Writes len bytes from the specified byte array starting at offset off to the underlying output stream. If no exception is thrown, the counter written is incremented by len.

    Specified by:

    write in interface DataOutput

    Overrides:

    write in class FilterOutputStream

    Parameters:

    b - the data.

    off - the start offset in the data.

    len - the number of bytes to write.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out

  • flush

    Flushes this data output stream. This forces any buffered output bytes to be written out to the stream.

    The flush method of DataOutputStream calls the flush method of its underlying output stream.

    Specified by:

    flush in interface Flushable

    Overrides:

    flush in class FilterOutputStream

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out, OutputStream.flush()

  • writeBoolean

    public final void writeBoolean​(boolean v) throws IOException

    Writes a boolean to the underlying output stream as a 1-byte value. The value true is written out as the value (byte)1; the value false is written out as the value (byte)0. If no exception is thrown, the counter written is incremented by 1.

    Specified by:

    writeBoolean in interface DataOutput

    Parameters:

    v - a boolean value to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out

  • writeByte

    public final void writeByte​(int v) throws IOException

    Writes out a byte to the underlying output stream as a 1-byte value. If no exception is thrown, the counter written is incremented by 1.

    Specified by:

    writeByte in interface DataOutput

    Parameters:

    v - a byte value to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out

  • writeShort

    public final void writeShort​(int v) throws IOException

    Writes a short to the underlying output stream as two bytes, high byte first. If no exception is thrown, the counter written is incremented by 2.

    Specified by:

    writeShort in interface DataOutput

    Parameters:

    v - a short to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out

  • writeChar

    public final void writeChar​(int v) throws IOException

    Writes a char to the underlying output stream as a 2-byte value, high byte first. If no exception is thrown, the counter written is incremented by 2.

    Specified by:

    writeChar in interface DataOutput

    Parameters:

    v - a char value to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out

  • writeInt

    public final void writeInt​(int v) throws IOException

    Writes an int to the underlying output stream as four bytes, high byte first. If no exception is thrown, the counter written is incremented by 4.

    Specified by:

    writeInt in interface DataOutput

    Parameters:

    v - an int to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out

  • writeLong

    public final void writeLong​(long v) throws IOException

    Writes a long to the underlying output stream as eight bytes, high byte first. In no exception is thrown, the counter written is incremented by 8.

    Specified by:

    writeLong in interface DataOutput

    Parameters:

    v - a long to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out

  • writeFloat

    public final void writeFloat​(float v) throws IOException

    Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the underlying output stream as a 4-byte quantity, high byte first. If no exception is thrown, the counter written is incremented by 4.

    Specified by:

    writeFloat in interface DataOutput

    Parameters:

    v - a float value to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out, Float.floatToIntBits(float)

  • writeDouble

    public final void writeDouble​(double v) throws IOException

    Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the underlying output stream as an 8-byte quantity, high byte first. If no exception is thrown, the counter written is incremented by 8.

    Specified by:

    writeDouble in interface DataOutput

    Parameters:

    v - a double value to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out, Double.doubleToLongBits(double)

  • writeBytes

    Writes out the string to the underlying output stream as a sequence of bytes. Each character in the string is written out, in sequence, by discarding its high eight bits. If no exception is thrown, the counter written is incremented by the length of s.

    Specified by:

    writeBytes in interface DataOutput

    Parameters:

    s - a string of bytes to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    FilterOutputStream.out

  • writeChars

    Writes a string to the underlying output stream as a sequence of characters. Each character is written to the data output stream as if by the writeChar method. If no exception is thrown, the counter written is incremented by twice the length of s.

    Specified by:

    writeChars in interface DataOutput

    Parameters:

    s - a String value to be written.

    Throws:

    IOException - if an I/O error occurs.

    See Also:

    writeChar(int), FilterOutputStream.out

  • writeUTF

    Writes a string to the underlying output stream using modified UTF-8 encoding in a machine-independent manner.

    First, two bytes are written to the output stream as if by the writeShort method giving the number of bytes to follow. This value is the number of bytes actually written out, not the length of the string. Following the length, each character of the string is output, in sequence, using the modified UTF-8 encoding for the character. If no exception is thrown, the counter written is incremented by the total number of bytes written to the output stream. This will be at least two plus the length of str, and at most two plus thrice the length of str.

    Specified by:

    writeUTF in interface DataOutput

    Parameters:

    str - a string to be written.

    Throws:

    UTFDataFormatException - if the modified UTF-8 encoding of str would exceed 65535 bytes in length

    IOException - if some other I/O error occurs.

    See Also:

    writeChars(String)

  • size

    public final int size()

    Returns the current value of the counter written, the number of bytes written to this data output stream so far. If the counter overflows, it will be wrapped to Integer.MAX_VALUE.

    Returns:

    the value of the written field.

    See Also:

    written