java.io
Class DataOutputStream

java.lang.Object
  |
  +--java.io.OutputStream
        |
        +--java.io.DataOutputStream
All Implemented Interfaces:
DataOutput

public class DataOutputStream
extends OutputStream
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
protected  OutputStream out
          The output stream
 
Constructor Summary
DataOutputStream(OutputStream out)
          Creates a new data output stream to write data to the specified underlying output stream.
 
Method Summary
 void close()
          Closes this output stream and releases any system resources associated with the stream.
 void flush()
          Flushes this data output stream.
 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 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 UTF-8 encoding in a machine-independent manner.
 
Methods inherited from class java.io.OutputStream
write
 
Methods inherited from class java.lang.Object
equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 
Methods inherited from interface java.io.DataOutput
write
 

Field Detail

out

protected OutputStream out
The output stream
Constructor Detail

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.
Method Detail

close

public void close()
           throws IOException
Closes this output stream and releases any system resources associated with the stream.

The close method calls its flush method, and then calls the close method of its underlying output stream.

Overrides:
close in class OutputStream
Throws:
IOException - if an I/O error occurs.

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.

Overrides:
flush in class OutputStream
Throws:
IOException - if an I/O error occurs.

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 OutputStream
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.

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 OutputStream
Parameters:
b - the byte to be written.
Throws:
IOException - if an I/O error occurs.

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.
Parameters:
v - a boolean value to be written.
Throws:
IOException - if an I/O error occurs.

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.
Parameters:
v - a byte value to be written.
Throws:
IOException - if an I/O error occurs.

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.
Parameters:
v - a char value to be written.
Throws:
IOException - if an I/O error occurs.

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.
Parameters:
s - a String value to be written.
Throws:
IOException - if an I/O error occurs.
See Also:
writeChar(int)

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.
Parameters:
v - a double value to be written.
Throws:
IOException - if an I/O error occurs.
Since:
JDE 4.0.0
See Also:
Double.doubleToLongBits(double)

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.
Parameters:
v - a float value to be written.
Throws:
IOException - if an I/O error occurs.
Since:
JDE 4.0.0
See Also:
Float.floatToIntBits(float)

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.
Parameters:
v - an int to be written.
Throws:
IOException - if an I/O error occurs.

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.
Parameters:
v - a long to be written.
Throws:
IOException - if an I/O error occurs.

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.
Parameters:
v - a short to be written.
Throws:
IOException - if an I/O error occurs.

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.

Parameters:
str - a string to be written.
Throws:
IOException - if an I/O error occurs.



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