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§2.6 Class DataOutputStream

public  class  java.io.DataOutputStream
    extends  java.io.FilterOutputStream  (I-§2.12)
    implements java.io.DataOutput  (I-§2.25)
{
        // Fields
    protected int written;	§2.6.1

        // Constructors
    public DataOutputStream(OutputStream  out);	§2.6.2
// Methods public void flush(); §2.6.3 public final int size(); §2.6.4 public void write(byte b[], int off, int len); §2.6.5 public void write(int b); §2.6.6 public final void writeBoolean(boolean v); §2.6.7 public final void writeByte(int v); §2.6.8 public final void writeBytes(String s); §2.6.9 public final void writeChar(int v); §2.6.10 public final void writeChars(String s); §2.6.11 public final void writeDouble(double v); §2.6.12 public final void writeFloat(float v); §2.6.13 public final void writeInt(int v); §2.6.14 public final void writeLong(long v); §2.6.15 public final void writeShort(int v); §2.6.16 public final void writeUTF(String str); §2.6.17 }
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 (I-§2.5) to read the data back in.


Fields

written

protected int written
The number of bytes written to the data output stream.

Constructors

DataOutputStream

public DataOutputStream(OutputStream out)
Creates a new data output stream to write data to the specified underlying output stream (I-§2.12.1).

Parameters:
out - the underlying output stream

Methods

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 (I-§2.15.3) of its underlying output stream (I-§2.12.1).

Throws
IOException (I-§2.29)
If an I/O error occurs.
Overrides:
flush in class FilterOutputStream (I-§2.12.4).

size

public final int size()
Determines the number of bytes written to this data output stream.
Returns:
The value of the written field (I-§2.6.1).

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 (I-§2.12.1).

Parameters:
b - the data
off - the start offset in the data
len - the number of bytes to write
Throws
IOException (I-§2.29)
If an I/O error occurs.
Overrides:
write in class FilterOutputStream (I-§2.12.6).

write

public void write(int b) throws IOException
Writes the specified byte to the underlying output stream (I-§2.12.1).

Parameters:
b - the byte to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.
Overrides:
write in class FilterOutputStream (I-§2.12.7).

writeBoolean

public final void writeBoolean(boolean v) throws IOException
Writes a boolean to the underlying output stream (I-§2.12.1) as a one-byte value. The value true is written out as the value (byte)1; the value false is written out as the value (byte)0.

Parameters:
v - a boolean value to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

writeByte

public final void writeByte(int v) throws IOException
Writes out a byte to the underlying output stream (I-§2.12.1) as a one-byte value.

Parameters:
v - a byte value to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

writeBytes

public final void writeBytes(String s) throws IOException
Writes out the string to the underlying output stream (I-§2.12.1) as a sequence of bytes. Each character in the string is written out, in sequence, by discarding its high eight bits.

Parameters:
s - a string of bytes to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

writeChar

public final void writeChar(int v) throws IOException
Writes a char to the underlying output stream (I-§2.12.1) as a two-byte value, high byte first.

Parameters:
v - a char value to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

writeChars

public final void writeChars(String s) throws IOException
Writes a string to the underlying output stream (I-§2.12.1) as a sequence of characters. Each character is written to the data output stream as if by the writeChar method (I-§2.6.10).

Parameters:
s - a String value to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

writeDouble

public final void writeDouble(double v) throws IOException
Converts the double argument to a long using the doubleToLongBits method (I-§1.6.8) in class Double, and then writes that long value to the underlying output stream (I-§2.12.1) as an eight-byte quantity, high-byte first.

Parameters:
v - a double value to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

writeFloat

public final void writeFloat(float v) throws IOException
Converts the float argument to an int using the floatToIntBits method (I-§1.7.11) in class Float, and then writes that int value to the underlying output stream (I-§2.12.1) as a four-byte quantity, high-byte first

Parameters:
v - a float value to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

writeInt

public final void writeInt(int v) throws IOException
Writes an int to the underlying output stream (I-§2.12.1) as four bytes, high-byte first.

Parameters:
v - an int to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

writeLong

public final void writeLong(long v) throws IOException
Writes a long to the underlying output stream (I-§2.12.1) as eight bytes, high-byte first.

Parameters:
v - a long to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

writeShort

public final void writeShort(int v) throws IOException
Writes a short to the underlying output stream (I-§2.12.1) as two bytes, high-byte first.

Parameters:
v - a short to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

writeUTF

public final void writeUTF(String str) throws IOException
Writes out a string to the underlying output stream (I-§2.12.1) using UTF-8 encoding in a machine-independent manner.


First, two bytes are written to the output stream as if by the writeShort method (I-§2.6.16) 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 (page I-225) for each character.

Parameters:
str - a string to be written
Throws
IOException (I-§2.29)
If an I/O error occurs.

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