DataOutputStream
public class DataOutputStream
extends FilterOutputStream
implements DataOutput
java.lang.Object | |||
↳ | java.io.OutputStream | ||
↳ | java.io.FilterOutputStream | ||
↳ | java.io.DataOutputStream |
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.
See also:
Summary
Fields | |
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protected int | written The number of bytes written to the data output stream so far. |
Inherited fields |
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Public constructors | |
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DataOutputStream(OutputStream out) Creates a new data output stream to write data to the specified underlying output stream. |
Public methods | |
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void | flush() Flushes this data output stream. |
final int | size() Returns the current value of the counter |
void | write(byte[] b, int off, int len) Writes |
void | write(int b) Writes the specified byte (the low eight bits of the argument |
final void | writeBoolean(boolean v) Writes a |
final void | writeByte(int v) Writes out a |
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 |
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 |
final void | writeFloat(float v) Converts the float argument to an |
final void | writeInt(int v) Writes an |
final void | writeLong(long v) Writes a |
final void | writeShort(int v) Writes a |
final void | writeUTF(String str) Writes a string to the underlying output stream using modified UTF-8 encoding in a machine-independent manner. |
Inherited methods | |
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Fields
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.
Public constructors
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 | |
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out | OutputStream : the underlying output stream, to be saved for later use. |
See also:
Public methods
flush
public void 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.
Throws | |
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IOException | if an I/O error occurs. |
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 | |
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int | the value of the written field. |
See also:
write
public 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. If no exception is thrown, the counter written
is incremented by len
.
Parameters | |
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b | byte : the data. |
off | int : the start offset in the data. |
len | int : the number of bytes to write. |
Throws | |
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IOException | if an I/O error occurs. |
See also:
write
public void write (int b)
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
.
Parameters | |
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b | int : the byte to be written. |
Throws | |
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IOException | if an I/O error occurs. |
See also:
writeBoolean
public final void writeBoolean (boolean v)
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
.
Parameters | |
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v | boolean : a boolean value to be written. |
Throws | |
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IOException | if an I/O error occurs. |
See also:
writeByte
public final void writeByte (int v)
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
.
Parameters | |
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v | int : a byte value to be written. |
Throws | |
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IOException | if an I/O error occurs. |
See also:
writeBytes
public final void writeBytes (String s)
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
.
Parameters | |
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s | String : a string of bytes to be written. |
Throws | |
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IOException | if an I/O error occurs. |
See also:
writeChar
public final void writeChar (int v)
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
.
Parameters | |
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v | int : a char value to be written. |
Throws | |
---|---|
IOException | if an I/O error occurs. |
See also:
writeChars
public final void writeChars (String s)
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
.
Parameters | |
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s | String : a String value to be written. |
Throws | |
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IOException | if an I/O error occurs. |
See also:
writeDouble
public 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. If no exception is thrown, the counter written
is incremented by 8
.
Parameters | |
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v | double : a double value to be written. |
Throws | |
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IOException | if an I/O error occurs. |
writeFloat
public 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. If no exception is thrown, the counter written
is incremented by 4
.
Parameters | |
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v | float : a float value to be written. |
Throws | |
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IOException | if an I/O error occurs. |
writeInt
public final void writeInt (int v)
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
.
Parameters | |
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v | int : an int to be written. |
Throws | |
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IOException | if an I/O error occurs. |
See also:
writeLong
public final void writeLong (long v)
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
.
Parameters | |
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v | long : a long to be written. |
Throws | |
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IOException | if an I/O error occurs. |
See also:
writeShort
public final void writeShort (int v)
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
.
Parameters | |
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v | int : a short to be written. |
Throws | |
---|---|
IOException | if an I/O error occurs. |
See also:
writeUTF
public final void writeUTF (String str)
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
.
Parameters | |
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str | String : a string to be written. |
Throws | |
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IOException | if an I/O error occurs. |