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RandomAccessFile (Java SE 26 & JDK 26)

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java.lang.Object

java.io.RandomAccessFile

All Implemented Interfaces: Closeable, DataInput, DataOutput, AutoCloseable

public class RandomAccessFile extends Object implements DataOutput, DataInput, Closeable

Instances of this class support both reading and writing to a random access file. A random access file behaves like a large array of bytes stored in the file system. There is a kind of cursor, or index into the implied array, called the file pointer; input operations read bytes starting at the file pointer and advance the file pointer past the bytes read. If the random access file is created in read/write mode, then output operations are also available; output operations write bytes starting at the file pointer and advance the file pointer past the bytes written. Output operations that write past the current end of the implied array cause the array to be extended. The file pointer can be read by the getFilePointer method and set by the seek method.

It is generally true of all the reading routines in this class that if end-of-file is reached before the desired number of bytes has been read, an EOFException (which is a kind of IOException) is thrown. If any byte cannot be read for any reason other than end-of-file, an IOException other than EOFException is thrown. In particular, an IOException may be thrown if the stream has been closed.

Since: 1.0

Constructor Summary

Constructors

Constructor

Description

RandomAccessFile(File file, String mode)

Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument.

RandomAccessFile(String pathname, String mode)

Creates a random access file stream to read from, and optionally to write to, a file with the specified pathname.
Method Summary

All MethodsInstance MethodsConcrete Methods

Modifier and Type

Method

Description

void

close()

Closes this random access file stream and releases any system resources associated with the stream.

final FileChannel

getChannel()

Returns the unique FileChannel object associated with this file.

final FileDescriptor

getFD()

Returns the opaque file descriptor object associated with this stream.

long

getFilePointer()

Returns the current offset in this file.

long

length()

Returns the length of this file.

int

read()

Reads a byte of data from this file.

int

read(byte[] b)

Reads up to b.length bytes of data from this file into an array of bytes.

int

read(byte[] b, int off, int len)

Reads up to len bytes of data from this file into an array of bytes.

final boolean

readBoolean()

Reads a boolean from this file.

final byte

readByte()

Reads a signed eight-bit value from this file.

final char

readChar()

Reads a character from this file.

final double

readDouble()

Reads a double from this file.

final float

readFloat()

Reads a float from this file.

final void

readFully(byte[] b)

Reads b.length bytes from this file into the byte array, starting at the current file pointer.

final void

readFully(byte[] b, int off, int len)

Reads exactly len bytes from this file into the byte array, starting at the current file pointer.

final int

readInt()

Reads a signed 32-bit integer from this file.

final String

readLine()

Reads the next line of text from this file.

final long

readLong()

Reads a signed 64-bit integer from this file.

final short

readShort()

Reads a signed 16-bit number from this file.

final int

readUnsignedByte()

Reads an unsigned eight-bit number from this file.

final int

readUnsignedShort()

Reads an unsigned 16-bit number from this file.

final String

readUTF()

Reads in a string from this file.

void

seek(long pos)

Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs.

void

setLength(long newLength)

Sets the length of this file.

int

skipBytes(int n)

Attempts to skip over n bytes of input discarding the skipped bytes.

void

write(byte[] b)

Writes b.length bytes from the specified byte array to this file, starting at the current file pointer.

void

write(byte[] b, int off, int len)

Writes len bytes from the specified byte array starting at offset off to this file.

void

write(int b)

Writes the specified byte to this file.

final void

writeBoolean(boolean v)

Writes a boolean to the file as a one-byte value.

final void

writeByte(int v)

Writes a byte to the file as a one-byte value.

final void

writeBytes(String s)

Writes the string to the file as a sequence of bytes.

final void

writeChar(int v)

Writes a char to the file as a two-byte value, high byte first.

final void

writeChars(String s)

Writes a string to the file as a sequence of characters.

final void

writeDouble(double v)

Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the file as an eight-byte quantity, high byte first.

final void

writeFloat(float v)

Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the file as a four-byte quantity, high byte first.

final void

writeInt(int v)

Writes an int to the file as four bytes, high byte first.

final void

writeLong(long v)

Writes a long to the file as eight bytes, high byte first.

final void

writeShort(int v)

Writes a short to the file as two bytes, high byte first.

final void

writeUTF(String str)

Writes a string to the file using modified UTF-8 encoding in a machine-independent manner.

Methods declared in class Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Modifier and Type

Method

Description

protected Object

clone()

Creates and returns a copy of this object.

boolean

equals(Object obj)

Indicates whether some other object is "equal to" this one.

protected void

finalize()

Deprecated, for removal: This API element is subject to removal in a future version.
Finalization is deprecated and subject to removal in a future release.

final Class<?>

getClass()

Returns the runtime class of this Object.

int

hashCode()

Returns a hash code value for this object.

final void

notify()

Wakes up a single thread that is waiting on this object's monitor.

final void

notifyAll()

Wakes up all threads that are waiting on this object's monitor.

String

toString()

Returns a string representation of the object.

final void

wait()

Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

final void

wait(long timeoutMillis)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

final void

wait(long timeoutMillis, int nanos)

Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.

Constructor Details

RandomAccessFile

public RandomAccessFile(String pathname, String mode) throws FileNotFoundException

Creates a random access file stream to read from, and optionally to write to, a file with the specified pathname. If the file exists it is opened; if it does not exist and write mode is specified, a new file is created. Symbolic links are automatically redirected to the target of the link. A new FileDescriptor object is created to represent the connection to the file.
The mode argument specifies the access mode with which the file is to be opened. The permitted values and their meanings are as specified for the RandomAccessFile(File,String) constructor.
Parameters: pathname - the system-dependent pathname string mode - the access mode Throws: IllegalArgumentException - if the mode argument is not equal to one of "r", "rw", "rws", or "rwd" FileNotFoundException - if the mode is "r" but the given pathname string does not denote an existing regular file, or if the mode begins with "rw" but the given pathname string does not denote an existing, writable regular file and a new regular file of that pathname cannot be created, or if some other error occurs while opening or creating the file

RandomAccessFile

public RandomAccessFile(File file, String mode) throws FileNotFoundException

Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument. If the file exists it is opened; if it does not exist and write mode is specified, a new file is created. Symbolic links are automatically redirected to the target of the link. A new FileDescriptor object is created to represent the connection to the file.

The mode argument specifies the access mode in which the file is to be opened. The permitted values and their meanings are:

Access mode permitted values and meanings ValueMeaning"r" "rw" "rws" "rwd"

Open for reading only. Invoking any of the write methods of the resulting object will cause an IOException to be thrown.

Open for reading and writing. If the file does not already exist then an attempt will be made to create it.

Open for reading and writing, as with "rw", and also require that every update to the file's content or metadata be written synchronously to the underlying storage device.

Open for reading and writing, as with "rw", and also require that every update to the file's content be written synchronously to the underlying storage device.

The "rws" and "rwd" modes work much like the force(boolean) method of the FileChannel class, passing arguments of true and false, respectively, except that they always apply to every I/O operation and are therefore often more efficient. If the file resides on a local storage device then when an invocation of a method of this class returns it is guaranteed that all changes made to the file by that invocation will have been written to that device. This is useful for ensuring that critical information is not lost in the event of a system crash. If the file does not reside on a local device then no such guarantee is made.

The "rwd" mode can be used to reduce the number of I/O operations performed. Using "rwd" only requires updates to the file's content to be written to storage; using "rws" requires updates to both the file's content and its metadata to be written, which generally requires at least one more low-level I/O operation.

Parameters: file - the file object mode - the access mode, as described above Throws: IllegalArgumentException - if the mode argument is not equal to one of "r", "rw", "rws", or "rwd" FileNotFoundException - if the mode is "r" but the given file object does not denote an existing regular file, or if the mode begins with "rw" but the given file object does not denote an existing, writable regular file and a new regular file of that pathname cannot be created, or if some other error occurs while opening or creating the file See Also:

Method Details
- getFD
  public final FileDescriptor getFD() throws IOException
  
  Returns the opaque file descriptor object associated with this stream.
  Returns: the file descriptor object associated with this stream. Throws: IOException - if an I/O error occurs. See Also:
  - FileDescriptor
- getChannel
  
  public final FileChannel getChannel()
  
  Returns the unique FileChannel object associated with this file.
  The position of the returned channel will always be equal to this object's file-pointer offset as returned by the getFilePointer method. Changing this object's file-pointer offset, whether explicitly or by reading or writing bytes, will change the position of the channel, and vice versa. Changing the file's length via this object will change the length seen via the file channel, and vice versa.
  Returns: the file channel associated with this file Since: 1.4
- read
  
  public int read() throws IOException
  
  Reads a byte of data from this file. The byte is returned as an integer in the range 0 to 255 (0x00-0x0ff). This method blocks if no input is yet available.
  Although RandomAccessFile is not a subclass of InputStream, this method behaves in exactly the same way as the InputStream.read() method of InputStream.
  Returns: the next byte of data, or -1 if the end of the file has been reached. Throws: IOException - if an I/O error occurs. Not thrown if end-of-file has been reached.
- read
  
  public int read(byte[] b, int off, int len) throws IOException
  
  Reads up to len bytes of data from this file into an array of bytes. This method blocks until at least one byte of input is available.
  Although RandomAccessFile is not a subclass of InputStream, this method behaves in exactly the same way as the InputStream.read(byte[], int, int) method of InputStream.
  Parameters: b - the buffer into which the data is read. off - the start offset in array b at which the data is written. len - the maximum number of bytes read. Returns: the total number of bytes read into the buffer, or -1 if there is no more data because the end of the file has been reached. Throws: IOException - If the first byte cannot be read for any reason other than end of file, or if the random access file has been closed, or if some other I/O error occurs. NullPointerException - If b is null. IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off
- read
  
  public int read(byte[] b) throws IOException
  
  Reads up to 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.
  Although RandomAccessFile is not a subclass of InputStream, this method behaves in exactly the same way as the InputStream.read(byte[]) method of InputStream.
  Parameters: b - the buffer into which the data is read. Returns: the total number of bytes read into the buffer, or -1 if there is no more data because the end of this file has been reached. Throws: IOException - If the first byte cannot be read for any reason other than end of file, or if the random access file has been closed, or if some other I/O error occurs. NullPointerException - If b is null.
- readFully
  
  public final void readFully(byte[] b) throws IOException
  
  Reads b.length bytes from this file into the byte array, starting at the current file pointer. This method reads repeatedly from the file until the requested number of bytes are read. This method blocks until the requested number of bytes are read, the end of the stream is detected, or an exception is thrown.
  Specified by: readFully in interface DataInput Parameters: b - the buffer into which the data is read. Throws: NullPointerException - if b is null. EOFException - if this file reaches the end before reading all the bytes. IOException - if an I/O error occurs.
- readFully
  
  public final void readFully(byte[] b, int off, int len) throws IOException
  
  Reads exactly len bytes from this file into the byte array, starting at the current file pointer. This method reads repeatedly from the file until the requested number of bytes are read. This method blocks until the requested number of bytes are read, the end of the stream is detected, or an exception is thrown.
  Specified by: readFully in interface DataInput Parameters: b - the buffer into which the data is read. off - the start offset into the data array b. len - the number of bytes to read. Throws: NullPointerException - if b is null. IndexOutOfBoundsException - if off is negative, len is negative, or len is greater than b.length - off. EOFException - if this file reaches the end before reading all the bytes. IOException - if an I/O error occurs.
- skipBytes
  
  public int skipBytes(int n) throws IOException
  
  Attempts to skip over n bytes of input discarding the skipped bytes.
  This method may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. This method never throws an EOFException. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped.
  Specified by: skipBytes in interface DataInput Parameters: n - the number of bytes to be skipped. Returns: the actual number of bytes skipped. Throws: IOException - if an I/O error occurs.
- write
  
  public void write(int b) throws IOException
  
  Writes the specified byte to this file. The write starts at the current file pointer.
  Specified by: write in interface DataOutput Parameters: b - the byte to be written. Throws: IOException - if an I/O error occurs.
- write
  
  public void write(byte[] b) throws IOException
  
  Writes b.length bytes from the specified byte array to this file, starting at the current file pointer.
  Specified by: write in interface DataOutput Parameters: b - the data. Throws: IOException - if an I/O error occurs.
- write
  
  public void write(byte[] b, int off, int len) throws IOException
  
  Writes len bytes from the specified byte array starting at offset off to this file.
  Specified by: write in interface DataOutput Parameters: b - the data. off - the start offset in the data. len - the number of bytes to write. Throws: IOException - if an I/O error occurs. IndexOutOfBoundsException - If off is negative, len is negative, or len is greater than b.length - off
- getFilePointer
  
  public long getFilePointer() throws IOException
  
  Returns the current offset in this file.
  Returns: the offset from the beginning of the file, in bytes, at which the next read or write occurs. Throws: IOException - if an I/O error occurs.
- seek
  
  public void seek(long pos) throws IOException
  
  Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs. The offset may be set beyond the end of the file. Setting the offset beyond the end of the file does not change the file length. The file length will change only by writing after the offset has been set beyond the end of the file.
  Parameters: pos - the offset position, measured in bytes from the beginning of the file, at which to set the file pointer. Throws: IOException - if pos is less than 0 or if an I/O error occurs.
- length
  
  public long length() throws IOException
  
  Returns the length of this file.
  Returns: the length of this file, measured in bytes. Throws: IOException - if an I/O error occurs.
- setLength
  
  public void setLength(long newLength) throws IOException
  
  Sets the length of this file.
  If the present length of the file as returned by the length method is greater than the desired length of the file specified by the newLength argument, then the file will be truncated.
  If the present length of the file is smaller than the desired length, then the file will be extended. The contents of the extended portion of the file are not defined.
  If the present length of the file is equal to the desired length, then the file and its length will be unchanged.
  In all cases, after this method returns, the file offset as returned by the getFilePointer method will equal the minimum of the desired length and the file offset before this method was called, even if the length is unchanged. In other words, this method constrains the file offset to the closed interval [0,newLength].
  Parameters: newLength - The desired length of the file Throws: IOException - If the argument is negative or if some other I/O error occurs Since: 1.2
- close
  
  public void close() throws IOException
  
  Closes this random access file stream and releases any system resources associated with the stream. A closed random access file cannot perform input or output operations and cannot be reopened.
  If this file has an associated channel then the channel is closed as well.
  Specified by: close in interface AutoCloseable Specified by: close in interface Closeable API Note: If this stream has an associated channel then this method will close the channel, which in turn will close this stream. Subclasses that override this method should be prepared to handle possible reentrant invocation. Throws: IOException - if an I/O error occurs.
- readBoolean
  
  public final boolean readBoolean() throws IOException
  
  Reads a boolean from this file. This method reads a single byte from the file, starting at the current file pointer. 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.
  Specified by: readBoolean in interface DataInput Returns: the boolean value read. Throws: EOFException - if this file has reached the end. IOException - if an I/O error occurs.
- readByte
  
  public final byte readByte() throws IOException
  
  Reads a signed eight-bit value from this file. This method reads a byte from the file, starting from the current file pointer. If the byte read is b, where 0 <= b <= 255, then the result is:
  Copy (byte)(b)
  
  This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.
  Specified by: readByte in interface DataInput Returns: the next byte of this file as a signed eight-bit byte. Throws: EOFException - if this file has reached the end. IOException - if an I/O error occurs.
- readUnsignedByte
  
  public final int readUnsignedByte() throws IOException
  
  Reads an unsigned eight-bit number from this file. This method reads a byte from this file, starting at the current file pointer, and returns that byte.
  This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.
  Specified by: readUnsignedByte in interface DataInput Returns: the next byte of this file, interpreted as an unsigned eight-bit number. Throws: EOFException - if this file has reached the end. IOException - if an I/O error occurs.
- readShort
  
  public final short readShort() throws IOException
  
  Reads a signed 16-bit number from this file. The method reads two bytes from this file, starting at the current file pointer. If the two bytes read, in order, are b1 and b2, where each of the two values is between 0 and 255, inclusive, then the result is equal to:
  Copy (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.
  Specified by: readShort in interface DataInput Returns: the next two bytes of this file, interpreted as a signed 16-bit number. Throws: EOFException - if this file reaches the end before reading two bytes. IOException - if an I/O error occurs.
- readUnsignedShort
  
  public final int readUnsignedShort() throws IOException
  
  Reads an unsigned 16-bit number from this file. This method reads two bytes from the file, starting at the current file pointer. If the bytes read, in order, are b1 and b2, where 0 <= b1, b2 <= 255, then the result is equal to:
  Copy (b1 << 8) | b2
  
  This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.
  Specified by: readUnsignedShort in interface DataInput Returns: the next two bytes of this file, interpreted as an unsigned 16-bit integer. Throws: EOFException - if this file reaches the end before reading two bytes. IOException - if an I/O error occurs.
- readChar
  
  public final char readChar() throws IOException
  
  Reads a character from this file. This method reads two bytes from the file, starting at the current file pointer. If the bytes read, in order, are b1 and b2, where 0 <= b1, b2 <= 255, then the result is equal to:
  Copy (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.
  Specified by: readChar in interface DataInput Returns: the next two bytes of this file, interpreted as a char. Throws: EOFException - if this file reaches the end before reading two bytes. IOException - if an I/O error occurs.
- readInt
  
  public final int readInt() throws IOException
  
  Reads a signed 32-bit integer from this file. This method reads 4 bytes from the file, starting at the current file pointer. If the bytes read, in order, are b1, b2, b3, and b4, where 0 <= b1, b2, b3, b4 <= 255, then the result is equal to:
  Copy (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.
  Specified by: readInt in interface DataInput Returns: the next four bytes of this file, interpreted as an int. Throws: EOFException - if this file reaches the end before reading four bytes. IOException - if an I/O error occurs.
- readLong
  
  public final long readLong() throws IOException
  
  Reads a signed 64-bit integer from this file. This method reads eight bytes from the file, starting at the current file pointer. If the bytes read, in order, are b1, b2, b3, b4, b5, b6, b7, and b8, where:
  Copy 0 <= b1, b2, b3, b4, b5, b6, b7, b8 <= 255
  
  then the result is equal to:
  Copy ((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.
  Specified by: readLong in interface DataInput Returns: the next eight bytes of this file, interpreted as a long. Throws: EOFException - if this file reaches the end before reading eight bytes. IOException - if an I/O error occurs.
- readFloat
  public final float readFloat() throws IOException
  
  Reads a float from this file. This method reads an int value, starting at the current file pointer, 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.
  Specified by: readFloat in interface DataInput Returns: the next four bytes of this file, interpreted as a float. Throws: EOFException - if this file reaches the end before reading four bytes. IOException - if an I/O error occurs. See Also:
  - readInt()
  - Float.intBitsToFloat(int)
- readDouble
  public final double readDouble() throws IOException
  
  Reads a double from this file. This method reads a long value, starting at the current file pointer, 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.
  Specified by: readDouble in interface DataInput Returns: the next eight bytes of this file, interpreted as a double. Throws: EOFException - if this file reaches the end before reading eight bytes. IOException - if an I/O error occurs. See Also:
  - readLong()
  - Double.longBitsToDouble(long)
- readLine
  
  public final String readLine() throws IOException
  
  Reads the next line of text from this file. This method successively reads bytes from the file, starting at the current file pointer, until it reaches a line terminator or the end of the file. Each byte is converted into a character by taking the byte's value for the lower eight bits of the character and setting the high eight bits of the character to zero. This method does not, therefore, support the full Unicode character set.
  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 file. Line-terminating characters are discarded and are not 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 file is reached, or an exception is thrown.
  Specified by: readLine in interface DataInput Returns: the next line of text from this file, or null if end of file is encountered before even one byte is read. Throws: IOException - if an I/O error occurs.
- readUTF
  public final String readUTF() throws IOException
  
  Reads in a string from this file. The string has been encoded using a modified UTF-8 format.
  The first two bytes are read, starting from the current file pointer, 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 modified 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.
  Specified by: readUTF in interface DataInput Returns: a Unicode string. Throws: EOFException - if this file reaches the end before reading all the bytes. IOException - if an I/O error occurs. UTFDataFormatException - if the bytes do not represent valid modified UTF-8 encoding of a Unicode string. See Also:
  - readUnsignedShort()
- writeBoolean
  
  public final void writeBoolean(boolean v) throws IOException
  
  Writes a boolean to the file as a one-byte value. The value true is written out as the value (byte)1; the value false is written out as the value (byte)0. The write starts at the current position of the file pointer.
  Specified by: writeBoolean in interface DataOutput Parameters: v - a boolean value to be written. Throws: IOException - if an I/O error occurs.
- writeByte
  
  public final void writeByte(int v) throws IOException
  
  Writes a byte to the file as a one-byte value. The write starts at the current position of the file pointer.
  Specified by: writeByte in interface DataOutput Parameters: v - a byte value to be written. Throws: IOException - if an I/O error occurs.
- writeShort
  
  public final void writeShort(int v) throws IOException
  
  Writes a short to the file as two bytes, high byte first. The write starts at the current position of the file pointer.
  Specified by: writeShort in interface DataOutput Parameters: v - a short to be written. Throws: IOException - if an I/O error occurs.
- writeChar
  
  public final void writeChar(int v) throws IOException
  
  Writes a char to the file as a two-byte value, high byte first. The write starts at the current position of the file pointer.
  Specified by: writeChar in interface DataOutput Parameters: v - a char value to be written. Throws: IOException - if an I/O error occurs.
- writeInt
  
  public final void writeInt(int v) throws IOException
  
  Writes an int to the file as four bytes, high byte first. The write starts at the current position of the file pointer.
  Specified by: writeInt in interface DataOutput Parameters: v - an int to be written. Throws: IOException - if an I/O error occurs.
- writeLong
  
  public final void writeLong(long v) throws IOException
  
  Writes a long to the file as eight bytes, high byte first. The write starts at the current position of the file pointer.
  Specified by: writeLong in interface DataOutput Parameters: v - a long to be written. Throws: IOException - if an I/O error occurs.
- writeFloat
  public final void writeFloat(float v) throws IOException
  
  Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the file as a four-byte quantity, high byte first. The write starts at the current position of the file pointer.
  Specified by: writeFloat in interface DataOutput Parameters: v - a float value to be written. Throws: IOException - if an I/O error occurs. See Also:
  - Float.floatToIntBits(float)
- writeDouble
  public final void writeDouble(double v) throws IOException
  
  Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the file as an eight-byte quantity, high byte first. The write starts at the current position of the file pointer.
  Specified by: writeDouble in interface DataOutput Parameters: v - a double value to be written. Throws: IOException - if an I/O error occurs. See Also:
  - Double.doubleToLongBits(double)
- writeBytes
  
  public final void writeBytes(String s) throws IOException
  
  Writes the string to the file as a sequence of bytes. Each character in the string is written out, in sequence, by discarding its high eight bits. The write starts at the current position of the file pointer.
  Specified by: writeBytes in interface DataOutput Parameters: s - a string of bytes to be written. Throws: IOException - if an I/O error occurs.
- writeChars
  public final void writeChars(String s) throws IOException
  
  Writes a string to the file as a sequence of characters. Each character is written to the data output stream as if by the writeChar method. The write starts at the current position of the file pointer.
  Specified by: writeChars in interface DataOutput Parameters: s - a String value to be written. Throws: IOException - if an I/O error occurs. See Also:
  - writeChar(int)
- writeUTF
  
  public final void writeUTF(String str) throws IOException
  
  Writes a string to the file using modified UTF-8 encoding in a machine-independent manner.
  First, two bytes are written to the file, starting at the current file pointer, 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 modified UTF-8 encoding for each character.
  Specified by: writeUTF in interface DataOutput Parameters: str - a string to be written. Throws: IOException - if an I/O error occurs.

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Class RandomAccessFile

Constructor Summary

Method Summary

Methods declared in class Object

Constructor Details

RandomAccessFile

RandomAccessFile

Method Details

getFD

getChannel

read

read

read

readFully

readFully

skipBytes

write

write

write

getFilePointer

seek

length

setLength

close

readBoolean

readByte

readUnsignedByte

readShort

readUnsignedShort

readChar

readInt

readLong

readFloat

readDouble

readLine

readUTF

writeBoolean

writeByte

writeShort

writeChar

writeInt

writeLong

writeFloat

writeDouble

writeBytes

writeChars

writeUTF