java.lang.Object
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+--java.io.InputStream
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+--java.io.FilterInputStream
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+--java.io.DataInputStream
All Implemented Interfaces:DataInputStream(java.io.InputStream in) This constructor initializes a new |
int | read(byte[] b)This method reads bytes from the underlying stream into the specified byte array buffer. |
int | read(byte[] b, int off, int len)This method reads bytes from the underlying stream into the specified byte array buffer. |
boolean | readBoolean()This method reads a Java boolean value from an input stream. |
byte | readByte()This method reads a Java byte value from an input stream. |
char | readChar() This method reads a Java |
double | readDouble()This method reads a Java double value from an input stream. |
float | readFloat()This method reads a Java float value from an input stream. |
void | readFully(byte[] b)This method reads raw bytes into the passed array until the array is full. |
void | readFully(byte[] b, int off, int len)This method reads raw bytes into the passed array |
int | readInt()This method reads a Java |
java.lang.String | readLine()This method reads the next line of text data from an input stream. |
long | readLong() This method reads a Java long value from an input stream
It operates by reading eight bytes from the stream and converting them to
a single Java |
short | readShort()This method reads a signed 16-bit value into a Java in from the stream. |
java.lang.String | readUTF() This method reads a |
static java.lang.String | readUTF(java.io.DataInput in) This method reads a String encoded in UTF-8 format from the
specified |
int | readUnsignedByte() This method reads 8 unsigned bits into a Java |
int | readUnsignedShort()This method reads 16 unsigned bits into a Java int value from the stream. |
int | skipBytes(int n)This method attempts to skip and discard the specified number of bytes in the input stream. |
public DataInputStream(java.io.InputStream in)DataInputStream
to read from the specified subordinate stream.
in - The subordinate InputStream to read frompublic final int read(byte[] b)b - The buffer into which bytes will be read.IOException - If an error occurs.public final int read(byte[] b, int off, int len)len bytes and
will start storing them at position off into the buffer.
This method can return a short count if there is insufficient data
remaining to be read to complete the desired read length.
b - The buffer into which bytes will be read.off - The offset into the buffer to start storing bytes.len - The requested number of bytes to read.IOException - If an error occurs.public final boolean readBoolean()false. If the byte is non-zero, then
the value returned is true.
This method can read a boolean written by an object
implementing the writeBoolean() method in the
DataOutput interface.
boolean value readEOFException - If end of file is reached before reading
the booleanIOException - If any other error occurspublic final byte readByte()
This method can read a byte written by an object
implementing the writeByte() method in the
DataOutput interface.
byte value readEOFException - If end of file is reached before reading the byteIOException - If any other error occurspublic final char readChar()char value from an input stream.
It operates by reading two bytes from the stream and converting them to
a single 16-bit Java char. The two bytes are stored most
significant byte first (i.e., "big endian") regardless of the native
host byte ordering.
As an example, if byte1 and byte2
represent the first and second byte read from the stream
respectively, they will be transformed to a char in
the following manner:
(char)(((byte1 & 0xFF) << 8) | (byte2 & 0xFF)
This method can read a char written by an object
implementing the writeChar() method in the
DataOutput interface.
char value readEOFException - If end of file is reached before reading the charIOException - If any other error occurspublic final double readDouble()long value from the stream by calling the
readLong() method in this interface, then converts
that long to a double using the
longBitsToDouble method in the class
java.lang.Double
This method can read a double written by an object
implementing the writeDouble() method in the
DataOutput interface.
double value readEOFException - If end of file is reached before reading
the doubleIOException - If any other error occursjava.lang.Double
DataOutputpublic final float readFloat()int value from the
stream by calling the readInt() method in this
interface, then converts that int to a
float using the intBitsToFloat method
in the class java.lang.Float
This method can read a float written by an object
implementing the * writeFloat() method in the
DataOutput interface.
float value readEOFException - If end of file is reached before reading the floatIOException - If any other error occursjava.lang.Float
DataOutputpublic final void readFully(byte[] b)b - The buffer into which to read the dataEOFException - If end of file is reached before filling
the bufferIOException - If any other error occurspublic final void readFully(byte[] b, int off, int len)buf starting offset bytes into the
buffer. The number of bytes read will be exactly
len Note that this method blocks until the data is
available and * throws an exception if there is not enough data
left in the stream to read len bytes.
b - The buffer into which to read the dataoff - The offset into the buffer to start storing datalen - The number of bytes to read into the bufferEOFException - If end of file is reached before filling
the bufferIOException - If any other error occurspublic final int readInt()int value from an input
stream It operates by reading four bytes from the stream and
converting them to a single Java int The bytes are
stored most significant byte first (i.e., "big endian")
regardless of the native host byte ordering.
As an example, if byte1 through byte4
represent the first four bytes read from the stream, they will be
transformed to an int in the following manner:
(int)(((byte1 & 0xFF) << 24) + ((byte2 & 0xFF) << 16) +
((byte3 & 0xFF) << 8) + (byte4 & 0xFF)))
The value returned is in the range of 0 to 65535.
This method can read an int written by an object
implementing the writeInt() method in the
DataOutput interface.
int value readEOFException - If end of file is reached before reading the intIOException - If any other error occurspublic final String readLine()char values by treating the byte read as the low
eight bits of the char and using 0 as the high eight
bits. Because of this, it does not support the full 16-bit
Unicode character set.
The reading of bytes ends when either the end of file or a line
terminator is encountered. The bytes read are then returned as a
String A line terminator is a byte sequence
consisting of either \r, \n or
\r\n. These termination charaters are discarded and
are not returned as part of the string.
This method can read data that was written by an object implementing the
writeLine() method in DataOutput.
StringIOException - If an error occurspublic final long readLong()long The bytes are stored most
significant byte first (i.e., "big endian") regardless of the native
host byte ordering.
As an example, if byte1 through byte8
represent the first eight bytes read from the stream, they will
be transformed to an long in the following manner:
(long)((((long)byte1 & 0xFF) << 56) + (((long)byte2 & 0xFF) << 48) +
(((long)byte3 & 0xFF) << 40) + (((long)byte4 & 0xFF) << 32) +
(((long)byte5 & 0xFF) << 24) + (((long)byte6 & 0xFF) << 16) +
(((long)byte7 & 0xFF) << 8) + ((long)byte9 & 0xFF)))
The value returned is in the range of 0 to 65535.
This method can read an long written by an object
implementing the writeLong() method in the
DataOutput interface.
long value readEOFException - If end of file is reached before reading the longIOException - If any other error occurspublic final short readShort()short. The
two bytes are stored most significant byte first (i.e., "big
endian") regardless of the native host byte ordering.
As an example, if byte1 and byte2
represent the first and second byte read from the stream
respectively, they will be transformed to a short. in
the following manner:
(short)(((byte1 & 0xFF) << 8) | (byte2 & 0xFF)
The value returned is in the range of -32768 to 32767.
This method can read a short written by an object
implementing the writeShort() method in the
DataOutput interface.
short value readEOFException - If end of file is reached before reading the valueIOException - If any other error occurspublic final String readUTF()String from an input stream that
is encoded in a modified UTF-8 format. This format has a leading
two byte sequence that contains the remaining number of bytes to
read. This two byte sequence is read using the
readUnsignedShort() method of this interface.
After the number of remaining bytes have been determined, these
bytes are read an transformed into char values.
These char values are encoded in the stream using
either a one, two, or three byte format. The particular format
in use can be determined by examining the first byte read.
If the first byte has a high order bit of 0, then that character
consists on only one byte. This character value consists of
seven bits that are at positions 0 through 6 of the byte. As an
example, if byte1 is the byte read from the stream,
it would be converted to a char like so:
(char)byte1
If the first byte has 110 as its high order bits, then the character consists of two bytes. The bits that make up the character value are in positions 0 through 4 of the first byte and bit positions 0 through 5 of the second byte. (The second byte should have 10 as its high order bits). These values are in most significant byte first (i.e., "big endian") order.
As an example, if byte1 and byte2 are
the first two bytes read respectively, and the high order bits of
them match the patterns which indicate a two byte character
encoding, then they would be converted to a Java
char like so:
(char)(((byte1 & 0x1F) << 6) | (byte2 & 0x3F))
If the first byte has a 1110 as its high order bits, then the character consists of three bytes. The bits that make up the character value are in positions 0 through 3 of the first byte and bit positions 0 through 5 of the other two bytes. (The second and third bytes should have 10 as their high order bits). These values are in most significant byte first (i.e., "big endian") order.
As an example, if byte1 byte2 and
byte3 are the three bytes read, and the high order
bits of them match the patterns which indicate a three byte
character encoding, then they would be converted to a Java
char like so:
(char)(((byte1 & 0x0F) << 12) | ((byte2 & 0x3F) << 6) | (byte3 & 0x3F))
Note that all characters are encoded in the method that requires
the fewest number of bytes with the exception of the character
with the value of \u0000 which is encoded as two
bytes. This is a modification of the UTF standard used to
prevent C language style NUL values from appearing
in the byte stream.
This method can read data that was written by an object implementing the
writeUTF() method in DataOutput
EOFException - If end of file is reached before reading
the StringUTFDataFormatException - If the data is not in UTF-8 formatIOException - If any other error occurspublic static final String readUTF(java.io.DataInput in)DataInput source.
in - The DataInput source to read fromIOException - If an error occurspublic final int readUnsignedByte()int
value from the stream. The value returned is in the range of 0 to
255.
This method can read an unsigned byte written by an object
implementing the writeUnsignedByte() method in the
DataOutput interface.
int.EOFException - If end of file is reached before reading the valueIOException - If any other error occurspublic final int readUnsignedShort()int The two bytes are stored most
significant byte first (i.e., "big endian") regardless of the native
host byte ordering.
As an example, if byte1 and byte2
represent the first and second byte read from the stream
respectively, they will be transformed to an int in
the following manner:
(int)(((byte1 & 0xFF) << 8) + (byte2 & 0xFF))
The value returned is in the range of 0 to 65535.
This method can read an unsigned short written by an object
implementing the writeUnsignedShort() method in the
DataOutput interface.
intEOFException - If end of file is reached before reading the valueIOException - If any other error occurspublic final int skipBytes(int n)n - The requested number of bytes to skip.IOException - If an error occurs.
FilteredInputStreamimplements theDataInputinterface that provides method for reading primitive Java data types from a stream.