Class java.io.RandomAccessFile
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Class java.io.RandomAccessFile
java.lang.Object
|
+----java.io.RandomAccessFile
- public class RandomAccessFile
- extends Object
- implements DataOutput, DataInput
Random access files can be constructed from file descriptors, file
names, or file objects. This class provides a sense of security
by offering methods that allow specified mode accesses of
read-only or read-write to files.
-
RandomAccessFile(String, String)
- Creates a RandomAccessFile with the specified system dependent
file name and the specified mode.
-
RandomAccessFile(File, String)
- Creates a RandomAccessFile from a specified File object
and mode ("r" or "rw").
-
close()
- Closes the file.
-
getFD()
- Returns the opaque file descriptor object.
-
getFilePointer()
- Returns the current location of the file pointer.
-
length()
- Returns the length of the file.
-
read()
- Reads a byte of data.
-
read(byte[], int, int)
- Reads a sub array as a sequence of bytes.
-
read(byte[])
- Reads data into an array of bytes.
-
readBoolean()
- Reads a boolean.
-
readByte()
- Reads a byte.
-
readChar()
- Reads a 16 bit char.
-
readDouble()
- Reads a 64 bit double.
-
readFloat()
- Reads a 32 bit float.
-
readFully(byte[])
- Reads bytes, blocking until all bytes are read.
-
readFully(byte[], int, int)
- Reads bytes, blocking until all bytes are read.
-
readInt()
- Reads a 32 bit int.
-
readLine()
- Reads a line terminated by a '\n' or EOF.
-
readLong()
- Reads a 64 bit long.
-
readShort()
- Reads 16 bit short.
-
readUTF()
- Reads a UTF formatted String.
-
readUnsignedByte()
- Reads an unsigned 8 bit byte.
-
readUnsignedShort()
- Reads 16 bit short.
-
seek(long)
- Sets the file pointer to the specified absolute position.
-
skipBytes(int)
-
-
write(int)
- Writes a byte of data.
-
write(byte[])
- Writes an array of bytes.
-
write(byte[], int, int)
- Wrotes a sub array of bytes.
-
writeBoolean(boolean)
- Writes a boolean.
-
writeByte(int)
- Writes a byte.
-
writeBytes(String)
- Writes a String as a sequence of bytes.
-
writeChar(int)
- Writes a character.
-
writeChars(String)
- Writes a String as a sequence of chars.
-
writeDouble(double)
-
-
writeFloat(float)
-
-
writeInt(int)
- Writes an integer.
-
writeLong(long)
- Writes a long.
-
writeShort(int)
- Writes a short.
-
writeUTF(String)
- Writes a String in UTF format.
RandomAccessFile
public RandomAccessFile(String name,
String mode) throws IOException
- Creates a RandomAccessFile with the specified system dependent
file name and the specified mode.
Mode "r" is for read-only and mode "rw" is for read+write.
- Parameters:
- name - the system dependent file name
- mode - the access mode
- Throws: IOException
- If an I/O error has occurred.
RandomAccessFile
public RandomAccessFile(File file,
String mode) throws IOException
- Creates a RandomAccessFile from a specified File object
and mode ("r" or "rw").
- Parameters:
- file - the file object
- mode - the access mode
getFD
public final FileDescriptor getFD() throws IOException
- Returns the opaque file descriptor object.
- Returns:
- the file descriptor.
read
public int read() throws IOException
- Reads a byte of data. This method will block if no input is
available.
- Returns:
- the byte read, or -1 if the end of the
stream is reached.
- Throws: IOException
- If an I/O error has occurred.
read
public int read(byte b[],
int off,
int len) throws IOException
- Reads a sub array as a sequence of bytes.
- Parameters:
- b - the data to be written
- off - the start offset in the data
- len - the number of bytes that are written
- Throws: IOException
- If an I/O error has occurred.
read
public int read(byte b[]) throws IOException
- Reads data into an array of bytes. This method blocks
until some input is available.
- Returns:
- the actual number of bytes read, -1 is
returned when the end of the stream is reached.
- Throws: IOException
- If an I/O error has occurred.
readFully
public final void readFully(byte b[]) throws IOException
- Reads bytes, blocking until all bytes are read.
- Parameters:
- b - the buffer into which the data is read
- Returns:
- the actual number of bytes read, -1 is
returned when the end of the stream is reached.
- Throws: IOException
- If an I/O error has occurred.
readFully
public final void readFully(byte b[],
int off,
int len) throws IOException
- Reads bytes, blocking until all bytes are read.
- Parameters:
- b - the buffer into which the data is read
- off - the start offset of the data
- len - the maximum number of bytes read
- Returns:
- the actual number of bytes read, -1 is
returned when the end of the stream is reached.
- Throws: IOException
- If an I/O error has occurred.
skipBytes
public int skipBytes(int n) throws IOException
write
public void write(int b) throws IOException
- Writes a byte of data. This method will block until the byte
is actually written.
- Parameters:
- b - the byte to be written
- Throws: IOException
- If an I/O error has occurred.
write
public void write(byte b[]) throws IOException
- Writes an array of bytes. Will block until the bytes
are actually written.
- Parameters:
- b - the data to be written
- Throws: IOException
- If an I/O error has occurred.
write
public void write(byte b[],
int off,
int len) throws IOException
- Wrotes a sub array of bytes.
- Parameters:
- b - the data to be written
- off - the start offset in the data
- len - the number of bytes that are written
- Throws: IOException
- If an I/O error has occurred.
getFilePointer
public long getFilePointer() throws IOException
- Returns the current location of the file pointer.
seek
public void seek(long pos) throws IOException
- Sets the file pointer to the specified absolute position.
- Parameters:
- pos - the absolute position
length
public long length() throws IOException
- Returns the length of the file.
close
public void close() throws IOException
- Closes the file.
- Throws: IOException
- If an I/O error has occurred.
readBoolean
public final boolean readBoolean() throws IOException
- Reads a boolean.
readByte
public final byte readByte() throws IOException
- Reads a byte.
readUnsignedByte
public final int readUnsignedByte() throws IOException
- Reads an unsigned 8 bit byte.
- Returns:
- the 8 bit byte read.
readShort
public final short readShort() throws IOException
- Reads 16 bit short.
- Returns:
- the read 16 bit short.
readUnsignedShort
public final int readUnsignedShort() throws IOException
- Reads 16 bit short.
- Returns:
- the read 16 bit short.
readChar
public final char readChar() throws IOException
- Reads a 16 bit char.
- Returns:
- the read 16 bit char.
readInt
public final int readInt() throws IOException
- Reads a 32 bit int.
- Returns:
- the read 32 bit integer.
readLong
public final long readLong() throws IOException
- Reads a 64 bit long.
- Returns:
- the read 64 bit long.
readFloat
public final float readFloat() throws IOException
- Reads a 32 bit float.
- Returns:
- the read 32 bit float.
readDouble
public final double readDouble() throws IOException
- Reads a 64 bit double.
- Returns:
- the read 64 bit double.
readLine
public final String readLine() throws IOException
- Reads a line terminated by a '\n' or EOF.
readUTF
public final String readUTF() throws IOException
- Reads a UTF formatted String.
writeBoolean
public final void writeBoolean(boolean v) throws IOException
- Writes a boolean.
- Parameters:
- v - the boolean value
writeByte
public final void writeByte(int v) throws IOException
- Writes a byte.
- Parameters:
- v - the byte
writeShort
public final void writeShort(int v) throws IOException
- Writes a short.
- Parameters:
- v - the short
writeChar
public final void writeChar(int v) throws IOException
- Writes a character.
- Parameters:
- v - the char
writeInt
public final void writeInt(int v) throws IOException
- Writes an integer.
- Parameters:
- v - the integer
writeLong
public final void writeLong(long v) throws IOException
- Writes a long.
- Parameters:
- v - the long
writeFloat
public final void writeFloat(float v) throws IOException
writeDouble
public final void writeDouble(double v) throws IOException
writeBytes
public final void writeBytes(String s) throws IOException
- Writes a String as a sequence of bytes.
- Parameters:
- s - the String
writeChars
public final void writeChars(String s) throws IOException
- Writes a String as a sequence of chars.
- Parameters:
- s - the String
writeUTF
public final void writeUTF(String str) throws IOException
- Writes a String in UTF format.
- Parameters:
- str - the String
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