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java.lang.Object
|
+----java.io.RandomAccessFile
File
argument.
b.length
bytes of data from this file
into an array of bytes.
len
bytes of data from this file into an
array of bytes.
boolean
from this file.
double
from this file.
float
from this file.
b.length
bytes from this file into the byte
array.
len
bytes from this file into the byte
array.
n
bytes of input.
b.length
bytes from the specified byte array
starting at offset off
to this file.
len
bytes from the specified byte array
starting at offset off
to this file.
boolean
to the file as a 1-byte value.
byte
to the file as a 1-byte value.
char
to the file as a 2-byte value, high
byte first.
long
using the
doubleToLongBits
method in class Double
,
and then writes that long
value to the file as an
8-byte quantity, high byte first.
int
using the
floatToIntBits
method in class Float
,
and then writes that int
value to the file as a
4-byte quantity, high byte first.
int
to the file as four bytes, high byte first.
long
to the file as eight bytes, high byte first.
short
to the file as two bytes, high byte first.
public RandomAccessFile(String name,
String mode) throws IOException
The mode argument must either be equal to "r"
or
"rw"
, indicating either to open the file for input or
for both input and output.
"r"
or to "rw"
.
checkRead
method is called with the name
argument to see if the application is allowed read access
to the file. If the mode argument is equal to
"rw"
, its checkWrite
method also
is called with the name argument to see if the application
is allowed write access to the file. Either of these may
result in a security exception.
public RandomAccessFile(File file,
String mode) throws IOException
File
argument.
The mode argument must either be equal to "r"
or to
"rw"
, indicating either to open the file for input,
or for both input and output, respectively.
"r"
or to "rw"
.
checkRead
method is called with the pathname
of the File
argument to see if the
application is allowed read access to the file. If the
mode argument is equal to "rw"
, its
checkWrite
method also is called with the
pathname to see if the application is allowed write access
to the file.
public final FileDescriptor getFD() throws IOException
public native int read() throws IOException
-1
if the end of the
file is reached.
public int read(byte b[],
int off,
int len) throws IOException
len
bytes of data from this file into an
array of bytes. This method blocks until at least one byte of input
is available.
-1
if there is no more data because the end of
the file has been reached.
public int read(byte b[]) throws IOException
b.length
bytes of data from this file
into an array of bytes. This method blocks until at least one byte
of input is available.
-1
if there is no more data because the end of
this file has been reached.
public final void readFully(byte b[]) throws IOException
b.length
bytes from this file into the byte
array. This method reads repeatedly from the file until all the
bytes are read. This method blocks until all the bytes are read,
the end of the stream is detected, or an exception is thrown.
public final void readFully(byte b[],
int off,
int len) throws IOException
len
bytes from this file into the byte
array. This method reads repeatedly from the file until all the
bytes are read. This method blocks until all the bytes are read,
the end of the stream is detected, or an exception is thrown.
public int skipBytes(int n) throws IOException
n
bytes of input.
This method blocks until all the bytes are skipped, the end of the stream is detected, or an exception is thrown.
n
.
public native void write(int b) throws IOException
byte
to be written.
public void write(byte b[]) throws IOException
b.length
bytes from the specified byte array
starting at offset off
to this file.
public void write(byte b[],
int off,
int len) throws IOException
len
bytes from the specified byte array
starting at offset off
to this file.
public native long getFilePointer() throws IOException
public native void seek(long pos) throws IOException
public native long length() throws IOException
public native void close() throws IOException
public final boolean readBoolean() throws IOException
boolean
from this file. This method reads a
single byte from the file. A value of 0
represents
false
. Any other value represents true
.
This method blocks until the byte is read, the end of the stream
is detected, or an exception is thrown.
boolean
value read.
public final byte readByte() throws IOException
b
, where
0 <= b <= 255
,
then the result is:
(byte)(b)
This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.
byte
.
public final int readUnsignedByte() throws IOException
This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.
public final short readShort() throws IOException
b1
and b2
, where each of the two values is
between 0
and 255
, inclusive, then the
result is equal to:
(short)((b1 << 8) | b2)
This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.
public final int readUnsignedShort() throws IOException
b1
and b2
, where
0 <= b1, b2 <= 255
,
then the result is equal to:
(b1 << 8) | b2
This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.
public final char readChar() throws IOException
b1
and b2
, where
0 <= b1, b2 <= 255
,
then the result is equal to:
(char)((b1 << 8) | b2)
This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.
public final int readInt() throws IOException
b1
,
b2
, b3
, and b4
, where
0 <= b1, b2, b3, b4 <= 255
,
then the result is equal to:
(b1 << 24) | (b2 << 16) + (b3 << 8) + b4
This method blocks until the four bytes are read, the end of the stream is detected, or an exception is thrown.
int
.
public final long readLong() throws IOException
b1
, b2
, b3
,
b4
, b5
, b6
,
b7
, and b8,
where:
0 <= b1, b2, b3, b4, b5, b6, b7, b8 <=255,
then the result is equal to:
((long)b1 << 56) + ((long)b2 << 48)
+ ((long)b3 << 40) + ((long)b4 << 32)
+ ((long)b5 << 24) + ((long)b6 << 16)
+ ((long)b7 << 8) + b8
This method blocks until the eight bytes are read, the end of the stream is detected, or an exception is thrown.
long
.
public final float readFloat() throws IOException
float
from this file. This method reads an
int
value as if by the readInt
method
and then converts that int
to a float
using the intBitsToFloat
method in class
Float
.
This method blocks until the four bytes are read, the end of the stream is detected, or an exception is thrown.
float
.
public final double readDouble() throws IOException
double
from this file. This method reads a
long
value as if by the readLong
method
and then converts that long
to a double
using the longBitsToDouble
method in
class Double
.
This method blocks until the eight bytes are read, the end of the stream is detected, or an exception is thrown.
double
.
public final String readLine() throws IOException
A line of text is terminated by a carriage-return character
('\r'
), a newline character ('\n'
), a
carriage-return character immediately followed by a newline
character, or the end of the input stream. The line-terminating
character(s), if any, are included as part of the string returned.
This method blocks until a newline character is read, a carriage return and the byte following it are read (to see if it is a newline), the end of the stream is detected, or an exception is thrown.
public final String readUTF() throws IOException
The first two bytes are read as if by
readUnsignedShort
. This value gives the number of
following bytes that are in the encoded string, not
the length of the resulting string. The following bytes are then
interpreted as bytes encoding characters in the UTF-8 format
and are converted into characters.
This method blocks until all the bytes are read, the end of the stream is detected, or an exception is thrown.
public final void writeBoolean(boolean v) throws IOException
boolean
to the file 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
.
boolean
value to be written.
public final void writeByte(int v) throws IOException
byte
to the file as a 1-byte value.
byte
value to be written.
public final void writeShort(int v) throws IOException
short
to the file as two bytes, high byte first.
short
to be written.
public final void writeChar(int v) throws IOException
char
to the file as a 2-byte value, high
byte first.
char
value to be written.
public final void writeInt(int v) throws IOException
int
to the file as four bytes, high byte first.
int
to be written.
public final void writeLong(long v) throws IOException
long
to the file as eight bytes, high byte first.
long
to be written.
public final void writeFloat(float v) throws IOException
int
using the
floatToIntBits
method in class Float
,
and then writes that int
value to the file as a
4-byte quantity, high byte first.
float
value to be written.
public final void writeDouble(double v) throws IOException
long
using the
doubleToLongBits
method in class Double
,
and then writes that long
value to the file as an
8-byte quantity, high byte first.
double
value to be written.
public final void writeBytes(String s) throws IOException
public final void writeChars(String s) throws IOException
writeChar
method.
String
value to be written.
public final void writeUTF(String str) throws IOException
First, two bytes are written to the file 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 each character.
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