java.io
Interface DataOutput
- ImageOutputStream, ObjectOutput
- DataOutputStream, FileCacheImageOutputStream, FileImageOutputStream, ImageOutputStreamImpl, MemoryCacheImageOutputStream, ObjectOutputStream, RandomAccessFile
This interface is implemented by classes that can wrte data to streams
from Java primitive types. This data can subsequently be read back
by classes implementing the DataInput interface.
void | write(byte[] buf)- This method writes the raw byte array passed in to the output stream.
|
void | write(byte[] buf, int offset, int len)- This method writes raw bytes from the passed array
buf
starting
offset bytes into the buffer.
|
void | write(int value)- This method writes an 8-bit value (passed into the method as a Java
int) to an output stream.
|
void | writeBoolean(boolean value)- This method writes a Java boolean value to an output stream.
|
void | writeByte(int value)- This method writes a Java byte value to an output stream.
|
void | writeBytes(String value)- This method writes all the bytes in a
String out to the
stream.
|
void | writeChar(int value)- This method writes a Java char value to an output stream.
|
void | writeChars(String value)- This method writes all the characters of a
String to an
output stream as an array of char's.
|
void | writeDouble(double value)- This method writes a Java
double value to the stream.
|
void | writeFloat(float value)- This method writes a Java
float value to the stream.
|
void | writeInt(int value)- This method writes a Java int value to an output stream.
|
void | writeLong(long value)- This method writes a Java long value to an output stream.
|
void | writeShort(int value)- This method writes a Java short value to an output stream.
|
void | writeUTF(String value)- This method writes a Java
String to the stream in a modified
UTF-8 format.
|
write
public void write(byte[] buf)
throws IOException This method writes the raw byte array passed in to the output stream.
buf - The byte array to write
write
public void write(byte[] buf,
int offset,
int len)
throws IOException This method writes raw bytes from the passed array buf
starting
offset bytes into the buffer. The number of bytes
written will be exactly len.
buf - The buffer from which to write the dataoffset - The offset into the buffer to start writing data fromlen - The number of bytes to write from the buffer to the output
stream
write
public void write(int value)
throws IOException This method writes an 8-bit value (passed into the method as a Java
int) to an output stream. The low 8 bits of the
passed value are written.
value - The byte to write to the output stream
writeBoolean
public void writeBoolean(boolean value)
throws IOException This method writes a Java boolean value to an output stream. If
value is true, a byte with the value of
1 will be written, otherwise a byte with the value of 0 will be
written.
The value written can be read using the readBoolean
method in DataInput.
value - The boolean value to write
writeByte
public void writeByte(int value)
throws IOException This method writes a Java byte value to an output stream. The
byte to be written will be in the lowest 8 bits of the
int value passed.
The value written can be read using the readByte or
readUnsignedByte methods in DataInput.
value - The int value to write
writeBytes
public void writeBytes(String value)
throws IOException This method writes all the bytes in a String out to the
stream. One byte is written for each character in the
String.
The high eight bits of each character are discarded, thus this
method is inappropriate for completely representing Unicode characters.
value - The String to write
writeChar
public void writeChar(int value)
throws IOException This method writes a Java char value to an output stream. The
char to be written will be in the lowest 16 bits of the
int
value passed. These bytes will be written "big endian". That is,
with the high byte written first in the following manner:
byte0 = (byte)((value & 0xFF00) >> 8);
byte1 = (byte)(value & 0x00FF);
The value written can be read using the
readChar
method in
DataInput.
value - The char value to write
writeChars
public void writeChars(String value)
throws IOException This method writes all the characters of a String to an
output stream as an array of char's. Each character
is written using the method specified in the writeChar
method.
value - The String to write
writeDouble
public void writeDouble(double value)
throws IOException This method writes a Java double value to the stream. This
value is written by first calling the method
Double.doubleToLongBits
to retrieve an long representing the floating point number,
then writing this long value to the stream exactly the same
as the writeLong() method does.
The value written can be read using the readDouble
method in DataInput.
value - The double value to write
writeFloat
public void writeFloat(float value)
throws IOException This method writes a Java float value to the stream. This
value is written by first calling the method
Float.floatToIntBits
to retrieve an int representing the floating point number,
then writing this int value to the stream exactly the same
as the writeInt() method does.
The value written can be read using the readFloat
method in DataInput.
value - The float value to write
writeInt
public void writeInt(int value)
throws IOException This method writes a Java int value to an output stream. The 4 bytes
of the passed value will be written "big endian". That is, with
the high byte written first in the following manner:
byte0 = (byte)((value & 0xFF000000) >> 24);
byte1 = (byte)((value & 0x00FF0000) >> 16);
byte2 = (byte)((value & 0x0000FF00) >> 8);
byte3 = (byte)(value & 0x000000FF);
The value written can be read using the
readInt
method in
DataInput.
value - The int value to write
writeLong
public void writeLong(long value)
throws IOException This method writes a Java long value to an output stream. The 8 bytes
of the passed value will be written "big endian". That is, with
the high byte written first in the following manner:
byte0 = (byte)((value & 0xFF00000000000000L) >> 56);
byte1 = (byte)((value & 0x00FF000000000000L) >> 48);
byte2 = (byte)((value & 0x0000FF0000000000L) >> 40);
byte3 = (byte)((value & 0x000000FF00000000L) >> 32);
byte4 = (byte)((value & 0x00000000FF000000L) >> 24);
byte5 = (byte)((value & 0x0000000000FF0000L) >> 16);
byte6 = (byte)((value & 0x000000000000FF00L) >> 8);
byte7 = (byte)(value & 0x00000000000000FFL);
The value written can be read using the
readLong
method in
DataInput.
value - The long value to write
writeShort
public void writeShort(int value)
throws IOException This method writes a Java short value to an output stream. The
char to be written will be in the lowest 16 bits of the
int
value passed. These bytes will be written "big endian". That is,
with the high byte written first in the following manner:
byte0 = (byte)((value & 0xFF00) >> 8);
byte1 = (byte)(value & 0x00FF);
The value written can be read using the
readShort and
readUnsignedShort methods in
DataInput.
value - The int value to write as a 16-bit value
writeUTF
public void writeUTF(String value)
throws IOException This method writes a Java String to the stream in a modified
UTF-8 format. First, two bytes are written to the stream indicating the
number of bytes to follow. This is written in the form of a Java
short value in the same manner used by the
writeShort method. Note that this is the number of
bytes in the
encoded String not the String length. Next
come the encoded characters. Each character in the String
is encoded as either one, two or three bytes. For characters in the
range of \u0001 to \u007F, one byte is used.
The character
value goes into bits 0-7 and bit eight is 0. For characters in the range
of \u0080 to \u007FF, two bytes are used. Bits
6-10 of the character value are encoded bits 0-4 of the first byte, with
the high bytes having a value of "110". Bits 0-5 of the character value
are stored in bits 0-5 of the second byte, with the high bits set to
"10". This type of encoding is also done for the null character
\u0000. This eliminates any C style NUL character values
in the output. All remaining characters are stored as three bytes.
Bits 12-15 of the character value are stored in bits 0-3 of the first
byte. The high bits of the first bytes are set to "1110". Bits 6-11
of the character value are stored in bits 0-5 of the second byte. The
high bits of the second byte are set to "10". And bits 0-5 of the
character value are stored in bits 0-5 of byte three, with the high bits
of that byte set to "10".
The value written can be read using the readUTF
method in DataInput.
value - The String to write
DataOutput.java -- Interface for writing data from a stream
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