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Class DataOutputStream

java.lang.Object

java.io.OutputStream

java.io.FilterOutputStream

java.io.DataOutputStream

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. A data output stream wraps another output stream and delegates writing bytes to the write methods of that output stream. Writing data consisting of more than a single byte may cause several writes to the underlying output stream.

A DataOutputStream is not safe for use by multiple concurrent threads. If a DataOutputStream is to be used by more than one thread then access to the data output stream should be controlled by appropriate synchronization.

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.

Fields declared in class FilterOutputStream
out
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.

final 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.

final void

writeBoolean(boolean v)

Writes a boolean to the underlying output stream as a 1-byte value.

final void

writeByte(int v)

Writes out a byte to the underlying output stream as a 1-byte value.

final void

writeBytes(String s)

Writes out the string to the underlying output stream as a sequence of bytes.

final void

writeChar(int v)

Writes a char to the underlying output stream as a 2-byte value, high byte first.

final void

writeChars(String s)

Writes a string to the underlying output stream as a sequence of characters.

final 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.

final 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.

final void

writeInt(int v)

Writes an int to the underlying output stream as four bytes, high byte first.

final void

writeLong(long v)

Writes a long to the underlying output stream as eight bytes, high byte first.

final void

writeShort(int v)

Writes a short to the underlying output stream as two bytes, high byte first.

final 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 FilterOutputStream
close, write

Methods declared in class OutputStream
nullOutputStream

Methods declared in class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods declared in interface DataOutput
write

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
  public DataOutputStream(OutputStream out)
  
  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
  public void write(int b) throws IOException
  
  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.
  
  IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off
  
  See Also:
  
  FilterOutputStream.out
- flush
  public void flush() throws IOException
  
  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
  public final void writeBytes(String s) throws IOException
  
  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
  public final void writeChars(String s) throws IOException
  
  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
  public final void writeUTF(String str) throws IOException
  
  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

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Class DataOutputStream

Field Summary

Fields declared in class FilterOutputStream

Constructor Summary

Method Summary

Methods declared in class FilterOutputStream

Methods declared in class OutputStream

Methods declared in class Object

Methods declared in interface DataOutput

Field Details

written

Constructor Details

DataOutputStream

Method Details

write

write

flush

writeBoolean

writeByte

writeShort

writeChar

writeInt

writeLong

writeFloat

writeDouble

writeBytes

writeChars

writeUTF

size