Class java.io.DataOutputStream
java.lang.Object
|
+----java.io.OutputStream
|
+----java.io.FilterOutputStream
|
+----java.io.DataOutputStream
- public class DataOutputStream
- extends FilterOutputStream
- implements DataOutput
A data input 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:
- JDK1.0
- See Also:
- DataInputStream
Field Summary
|
int
|
written
The number of bytes written to the data output stream so far.
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Constructor Summary
|
DataOutputStream(OutputStream out)
Creates a new data output stream to write data to the specified
underlying output stream.
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Method Summary
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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(int b)
Writes the specified byte (the low eight bits of the argument
b ) to the underlying output stream.
|
void
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write(byte[] b,
int off,
int len)
Writes len bytes from the specified byte array
starting at offset off to the underlying output stream.
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void
|
writeBoolean(boolean v)
Writes a boolean to the underlying output stream as
a 1-byte value.
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void
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writeByte(int v)
Writes out a byte to the underlying output stream as
a 1-byte value.
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void
|
writeBytes(String s)
Writes out the string to the underlying output stream as a
sequence of bytes.
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void
|
writeChar(int v)
Writes a char to the underlying output stream as a
2-byte value, high byte first.
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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.
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void
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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 UTF-8
encoding in a machine-independent manner.
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Methods inherited from class java.lang.Object
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clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
written
protected int written
- The number of bytes written to the data output stream so far.
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:
- out
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
.
- Implements:
- write in interface DataOutput
- Parameters:
b
- the byte
to be written.
- Throws:
- IOException - if an I/O error occurs.
- Overrides:
- write in class FilterOutputStream
- See Also:
- 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
.
- Implements:
- write in interface DataOutput
- 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.
- Overrides:
- write in class FilterOutputStream
- See Also:
- 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 DataOuputStream
calls the flush
method of its underlying output stream.
- Throws:
- IOException - if an I/O error occurs.
- Overrides:
- flush in class FilterOutputStream
- See Also:
- out, 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
.
- Implements:
- writeBoolean in interface DataOutput
- Parameters:
v
- a boolean
value to be written.
- Throws:
- IOException - if an I/O error occurs.
- See Also:
- 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
.
- Implements:
- writeByte in interface DataOutput
- Parameters:
v
- a byte
value to be written.
- Throws:
- IOException - if an I/O error occurs.
- See Also:
- 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
.
- Implements:
- writeShort in interface DataOutput
- Parameters:
v
- a short
to be written.
- Throws:
- IOException - if an I/O error occurs.
- See Also:
- 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
.
- Implements:
- writeChar in interface DataOutput
- Parameters:
v
- a char
value to be written.
- Throws:
- IOException - if an I/O error occurs.
- See Also:
- 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
.
- Implements:
- writeInt in interface DataOutput
- Parameters:
v
- an int
to be written.
- Throws:
- IOException - if an I/O error occurs.
- See Also:
- 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
.
- Implements:
- writeLong in interface DataOutput
- Parameters:
v
- a long
to be written.
- Throws:
- IOException - if an I/O error occurs.
- See Also:
- 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
.
- Implements:
- writeFloat in interface DataOutput
- Parameters:
v
- a float
value to be written.
- Throws:
- IOException - if an I/O error occurs.
- See Also:
- out, 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
.
- Implements:
- writeDouble in interface DataOutput
- Parameters:
v
- a double
value to be written.
- Throws:
- IOException - if an I/O error occurs.
- See Also:
- out, 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
.
- Implements:
- writeBytes in interface DataOutput
- Parameters:
s
- a string of bytes to be written.
- Throws:
- IOException - if an I/O error occurs.
- See Also:
- 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
.
- Implements:
- writeChars in interface DataOutput
- Parameters:
s
- a String
value to be written.
- Throws:
- IOException - if an I/O error occurs.
- See Also:
- writeChar(int), out
writeUTF
public final void writeUTF(String str) throws IOException
- Writes a string to the underlying output stream using 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 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
.
- Implements:
- writeUTF in interface DataOutput
- Parameters:
str
- a string to be written.
- Throws:
- 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.
- Returns:
- the value of the
written
field. - See Also:
- written
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