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Chapter 11 The java.io Package |
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DataOutputStream
Name
DataOutputStreamSynopsis
- Class Name:
-
java.io.DataOutputStream
- Superclass:
-
java.io.FilterOutputStream
- Immediate Subclasses:
-
None
- Interfaces Implemented:
-
java.io.DataOutput
- Availability:
-
JDK 1.0 or later
Description
The DataOutputStream class defines methods for writing primitive data types to an output stream in a machine-independent manner. Many of the methods of DataOutputStream write a single primitive data type, in binary format, to an underlying output stream. All multibyte quantities are written in a format that stores the most significant byte as the first byte and the least significant byte as the last byte.
Class Summary
public class java.io.DataOutputStream extends java.io.FilterOutputStream
implements java.io.DataOutput {
// Variables
protected int written;
// Constructors
public DataOutputStream(OutputStream out);
// Instance Methods
public void flush();
public final int size();
public synchronized void write(int b);
public synchronized void write(byte[] b, int off, int len);
public final void writeBoolean(boolean v);
public final void writeByte(int v);
public final void writeBytes(String s);
public final void writeChar(int v);
public final void writeChars(String s);
public final void writeDouble(double v);
public final void writeFloat(float v);
public final void writeInt(int v);
public final void writeLong(long v);
public final void writeShort(int v);
public final void writeUTF(String str);
}
Variables
written
protected int written
- Description
-
The number of bytes that have been written to this output stream.
Constructors
DataOutputStream
public DataOutputStream(OutputStream out)
- Parameters
-
- out
-
The output stream to use.
- out
- Description
-
This constructor creates a DataOutputStream that uses out as its underlying stream.
Instance Methods
flush
public void flush() throws IOException
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Overrides
-
FilterOutputStream.flush()
- Description
-
This method flushes the stream, forcing any buffered output to be written. The method calls the flush() method of the underlying output stream.
size
public final int size()
- Returns
-
The number of bytes written.
- Description
-
This method returns the number of bytes that have been written to the stream (i.e., it returns the value of the variable written).
write
public synchronized void write(int b) throws IOException
- Parameters
-
- b
-
The value to write.
- b
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Overrides
-
FilterOutputStream.write(int)
- Implements
-
DataOutput.write(int)
- Description
-
This method writes the low-order eight bits of b to the underlying stream as a byte.
public synchronized void write(byte b[], int off, int len) throws IOException
public synchronized void write(byte b[], int off, int len) throws IOException
- Parameters
-
- b
-
An array of bytes to write.
- off
-
An offset into the byte array.
- len
-
The number of bytes to write.
- b
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Overrides
-
FilterOutputStream.write(byte[], int, int)
- Implements
-
DataOutput.write(byte[], int, int)
- Description
-
This method writes len bytes from the given array, starting off elements from the beginning of the array, to the underlying stream.
writeBoolean
public final void writeBoolean(boolean v) throws IOException
- Parameters
-
- v
-
The boolean value to write.
- v
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeBoolean()
- Description
-
If v is true, this method writes a byte that contains the value 1 to the underlying stream. If v is false, the method writes a byte that contains the value 0.
writeByte
public final void writeByte(int v) throws IOException
- Parameters
-
- v
-
The value to write.
- v
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeByte()
- Description
-
This method writes an 8-bit byte to the underlying stream, using the low-order eight bits of the given integer v.
writeBytes
public final void writeBytes(String s) throws IOException
- Parameters
-
- s
-
The String to write.
- s
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeBytes()
- Description
-
This method writes the characters in the given String to the underlying stream as a sequence of 8-bit bytes. The high-order bytes of the characters in the string are ignored.
writeChar
public final void writeChar(int v) throws IOException
- Parameters
-
- v
-
The value to write.
- v
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeChar()
- Description
-
This method writes a 16-bit char to the underlying stream, using the low-order 16 bits of the given integer v.
writeChars
public final void writeChars(String s) throws IOException
- Parameters
-
- s
-
The String to write.
- s
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeChars()
- Description
-
This method writes the characters in the given String object to the underlying stream as a sequence of 16-bit characters.
writeDouble
public final void writeDouble(double v) throws IOException
- Parameters
-
- v
-
The double value to write.
- v
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeDouble()
- Description
-
This method writes a 64-bit double to the underlying stream. The double value is converted to a long using doubleToLongBits() of Double; the long value is then written to the underlying stream as eight bytes with the high-order byte first.
writeFloat
public final void writeFloat(float v) throws IOException
- Parameters
-
- v
-
The float value to write.
- v
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeFloat()
- Description
-
This method writes a 32-bit float to the underlying stream. The float value is converted to a int using floatToIntBits() of Float; the int value is then written to the underlying stream as four bytes with the high-order byte first.
writeInt
public final void writeInt(int v) throws IOException
- Parameters
-
- v
-
The int value to write.
- v
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeInt()
- Description
-
This method writes a 32-bit int to the underlying stream. The value is written as four bytes with the high-order byte first.
writeLong
public final void writeLong(long v) throws IOException
- Parameters
-
- v
-
The long value to write.
- v
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeLong()
- Description
-
This method writes a 64-bit long to the underlying stream. The value is written as eight bytes with the high-order byte first.
writeShort
public final void writeShort(int v) throws IOException
- Parameters
-
- v
-
The value to write.
- v
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeShort()
- Description
-
This method writes a 16-bit short to the underlying stream, using the low-order two bytes of the given integer v.
writeUTF
public final void writeUTF(String str) throws IOException
- Parameters
-
- str
-
The String to write.
- str
- Throws
-
- IOException
-
If any kind of I/O error occurs.
- IOException
- Implements
-
DataOutput.writeUTF()
- Description
-
This method writes the given String to the underlying stream using the UTF-8 encoding. First, two bytes are written as an unsigned short value; this value specifies the number of bytes to follow. The value is the actual number of bytes in the UTF-8 encoding, not the length of the string. Then each character of the string is written as UTF-8 encoded bytes.
See Appendix B, The UTF-8 Encoding for more information on the UTF-8 encoding.
Inherited Methods
|
Method |
Inherited From |
Method |
Inherited From |
|---|---|---|---|
|
clone() |
Object |
close() |
FilterOutputStream |
|
equals(Object) |
Object |
finalize() |
Object |
|
getClass() |
Object |
hashCode() |
Object |
|
notify() |
Object |
notifyAll() |
Object |
|
toString() |
Object |
wait() |
Object |
|
wait(long) |
Object |
wait(long, int) |
Object |
|
write(byte[]) |
FilterOutputStream |
See Also
DataInputStream, DataOutput, Double, FilterOutputStream, Float, IOException, OutputStream
|
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| DataOutput |  |
EOFException |
