public class DataOutputStream extends FilterOutputStream implements DataOutput
OutputStream in a portable way. Data written to
a stream using this class can be read back in using the
DataInputStream class on any platform.DataInputStream| Modifier and Type | Field and Description |
|---|---|
protected int |
written
This is the total number of bytes that have been written to the
stream by this object instance.
|
out| Constructor and Description |
|---|
DataOutputStream(OutputStream out)
This method initializes an instance of
DataOutputStream to
write its data to the specified underlying OutputStream |
| Modifier and Type | Method and Description |
|---|---|
void |
flush()
This method flushes any unwritten bytes to the underlying stream.
|
int |
size()
This method returns the total number of bytes that have been written to
the underlying output stream so far.
|
void |
write(byte[] buf,
int offset,
int len)
This method writes
len bytes from the specified byte array
buf starting at position offset into the
buffer to the underlying output stream. |
void |
write(int value)
This method writes the specified byte (passed as an
int)
to the underlying 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. |
close, writefinalizeclone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitwriteprotected int written
public DataOutputStream(OutputStream out)
DataOutputStream to
write its data to the specified underlying OutputStreamout - The subordinate OutputStream to which this
object will writepublic void flush()
throws IOException
flush in class FilterOutputStreamIOException - If an error occurs.public final int size()
written instance variablepublic void write(int value)
throws IOException
int)
to the underlying output stream.write in interface DataOutputwrite in class FilterOutputStreamvalue - The byte to write, passed as an int.IOException - If an error occurs.public void write(byte[] buf,
int offset,
int len)
throws IOException
len bytes from the specified byte array
buf starting at position offset into the
buffer to the underlying output stream.write in interface DataOutputwrite in class FilterOutputStreambuf - The byte array to write from.offset - The index into the byte array to start writing from.len - The number of bytes to write.IOException - If an error occurs.public final void writeBoolean(boolean value)
throws IOException
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.writeBoolean in interface DataOutputvalue - The boolean value to write to the streamIOException - If an error occursDataInput.readBoolean()public final void writeByte(int value)
throws IOException
int value passed.
The value written can be read using the readByte or
readUnsignedByte methods in DataInput.writeByte in interface DataOutputvalue - The byte to write to the stream, passed as
the low eight bits of an int.IOException - If an error occursDataInput.readByte(),
DataInput.readUnsignedByte()public final void writeShort(int value)
throws IOException
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.
writeShort in interface DataOutputvalue - The short value to write to the stream,
passed as an int.IOException - If an error occursDataInput.readShort(),
DataInput.readUnsignedShort()public final void writeChar(int value)
throws IOException
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.
writeChar in interface DataOutputvalue - The char value to write,
passed as an int.IOException - If an error occursDataInput.readChar()public final void writeInt(int value)
throws IOException
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.
writeInt in interface DataOutputvalue - The int value to write to the streamIOException - If an error occursDataInput.readInt()public final void writeLong(long value)
throws IOException
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.
writeLong in interface DataOutputvalue - The long value to write to the streamIOException - If an error occursDataInput.readLong()public final void writeFloat(float value)
throws IOException
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.writeFloat in interface DataOutputvalue - The float value to write to the streamIOException - If an error occurswriteInt,
DataInput.readFloat(),
Float.floatToIntBits(float)public final void writeDouble(double value)
throws IOException
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.writeDouble in interface DataOutputvalue - The double value to write to the streamIOException - If an error occurswriteLong,
DataInput.readDouble(),
Double.doubleToLongBits(double)public final void writeBytes(String value) throws IOException
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.writeBytes in interface DataOutputvalue - The String to write to the streamIOException - If an error occurspublic final void writeChars(String value) throws IOException
String to an
output stream as an array of char's. Each character
is written using the method specified in the writeChar
method.writeChars in interface DataOutputvalue - The String to write to the streamIOException - If an error occurswriteCharpublic final void writeUTF(String value) throws IOException
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. 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 ? to F, 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
. 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.writeUTF in interface DataOutputvalue - The String to write to the output in UTF formatIOException - If an error occursDataInput.readUTF()