java.io.RandomAccessFilegetFilePointer method and set by the seek
method.
public classIt 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, anRandomAccessFileimplements DataOutput, DataInput { publicRandomAccessFile(String path, String mode) throws SecurityException, IOException, IllegalArgumentException; publicRandomAccessFile(File file, String mode) throws SecurityException, IOException, IllegalArgumentException; public final FileDescriptorgetFD() throws IOException; public native longgetFilePointer() throws IOException; public native voidseek(long pos) throws IOException; public native longlength() throws IOException; public native voidclose() throws IOException; public native intread() throws IOException; public intread(byte[] b) throws IOException, NullPointerException; public intread(byte[] b, int off, int len) throws IOException, NullPointerException, IndexOutOfBoundsException; // The methods that implement interface DataInput: public final voidreadFully(byte[] b) throws IOException, NullPointerException; public final voidreadFully(byte[] b, int off, int len) throws IOException, NullPointerException, IndexOutOfBoundsException; public intskipBytes(int n) throws IOException; public final booleanreadBoolean() throws IOException; public final bytereadByte() throws IOException; public final intreadUnsignedByte() throws IOException; public final shortreadShort() throws IOException; public final intreadUnsignedShort() throws IOException; public final charreadChar() throws IOException; public final intreadInt() throws IOException; public final longreadLong() throws IOException; public final floatreadFloat() throws IOException; public final doublereadDouble() throws IOException; public final StringreadLine() throws IOException; public final StringreadUTF() throws IOException; // The methods that implement interface DataOutput: public native voidwrite(int b) throws IOException; public voidwrite(byte[] b) throws IOException, NullPointerException; public voidwrite(byte[] b, int off, int len) throws IOException, NullPointerException, IndexOutOfBoundsException; public final voidwriteBoolean(boolean v) throws IOException; public final voidwriteByte(int v) throws IOException; public final voidwriteShort(int v) throws IOException; public final voidwriteChar(int v) throws IOException; public final voidwriteInt(int v) throws IOException; public final voidwriteLong(long v) throws IOException; public final voidwriteFloat(float v) throws IOException; public final voidwriteDouble(double v) throws IOException; public final voidwriteBytes(String s) throws IOException; public final voidwriteChars(String s) throws IOException; public final voidwriteUTF(String str) throws IOException; }
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 (§22.23.7).22.23.1 public
RandomAccessFile(String path, String mode)
throws SecurityException, IOException, IllegalArgumentException
This constructor initializes a newly created RandomAccessFile by opening a
connection to an actual file, the file named by the path name path in the file system.
A new FileDescriptor object is created to represent this file connection.
First, if there is a security manager, its checkRead method (§20.17.19) is called with the path argument as its argument.
Next, if mode is "rw" and there is a security manager, its checkWrite method (§20.17.21) is called with the path argument as its argument.
If mode is "rw", then the file may be both read and written. If mode is "r", then the file may be read but may not be written (every write method for this object will simply throw an IOException). If mode is not "r" or "rw", then this constructor throws an IllegalArgumentException.
22.23.2 public
RandomAccessFile(File file, String mode)
throws SecurityException, IOException, IllegalArgumentException
This constructor initializes a newly created RandomAccessFile by opening a
connection to an actual file, the file named by file in the file system. A new
FileDescriptor object is created to represent this file connection.
First, if there is a security manager, its checkRead method (§20.17.19) is called with the path represented by the file argument as its argument.
Next, if mode is "rw" and there is a security manager, its checkWrite method (§20.17.21) is called with the path represented by the file argument as its argument.
If mode is "rw", then the file may be both read and written. If mode is "r", then the file may be read but may not be written (every write method for this object will simply throw an IOException). If mode is not "r" or "rw", then this constructor throws an IllegalArgumentException.
22.23.3 public final FileDescriptor
getFD() throws IOException
This method returns the FileDescriptor object (§22.26) that represents the connection
to the actual file in the file system being used by this RandomAccessFile.
22.23.4 public long
getFilePointer() throws IOException
The current file pointer for this random access file is returned. An IOException is
thrown if the file pointer cannot be read for any reason.
22.23.5 public void
seek(long pos) throws IOException
The file pointer for this random access file is set to pos, which is a position within
the file, measured in bytes. Position 0 is the start of the file. An IOException is
thrown if pos is less than zero or greater than the length of the file, or if the file
pointer cannot be set for any other reason.
22.23.6 public long
length() throws IOException
The length of this random access file, measured in bytes, is returned.
An IOException is thrown if the length cannot be read for any reason.
22.23.7 public void
close() throws IOException
This random access file is closed. A closed random access file cannot perform input or output operations and cannot be reopened.
22.23.8 public int
read() throws IOException
This method reads one byte from the random access file. The byte is returned as
an integer in the range 0 to 255 (0x00-0xff). If no byte is available because the
file pointer is at end of file, the value -1 is returned.
If the byte cannot be read for any reason other than end of file, an IOException is thrown. In particular, an IOException is thrown if the input stream has been closed (§22.23.7).
Although RandomAccessFile is not a subclass of InputStream, this method behaves in exactly the same way as the read method of InputStream (§22.3.1).
22.23.9 public int
read(byte[] b)
throws IOException, NullPointerException
Although RandomAccessFile is not a subclass of InputStream, this method
behaves in exactly the same way as the read method of InputStream (§22.3.2).
22.23.10 public int
read(byte[] b, int off, int len)
throws IOException, NullPointerException, IndexOutOfBoundsException
Although RandomAccessFile is not a subclass of InputStream, this method
behaves in exactly the same way as the read method of InputStream (§22.3.3).
22.23.11 public final void
readFully(byte[] b)
throws IOException, NullPointerException
See the general contract of the readFully method of DataInput (§22.1.1).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.12 public final void
readFully(byte[] b, int off, int len) throws IOException, NullPointerException, IndexOutOfBoundsException
See the general contract of the readFully method of DataInput (§22.1.2).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.13 public int
skipBytes(int n) throws IOException
See the general contract of the skipBytes method of DataInput (§22.1.3).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.14 public final boolean
readBoolean() throws IOException
See the general contract of the readBoolean method of DataInput (§22.1.4).
The byte for this operation is read from the random access file, starting at the current file pointer.
22.23.15 public final byte
readByte() throws IOException
See the general contract of the readByte method of DataInput (§22.1.5).
The byte for this operation is read from the random access file, starting at the current file pointer.
22.23.16 public final int
readUnsignedByte() throws IOException
See the general contract of the readUnsignedByte method of DataInput
(§22.1.6).
The byte for this operation is read from the random access file, starting at the current file pointer.
22.23.17 public final short
readShort() throws IOException
See the general contract of the readShort method of DataInput (§22.1.7).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.18 public final int
readUnsignedShort() throws IOException
See the general contract of the readUnsignedShort method of DataInput
(§22.1.8).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.19 public final char
readChar() throws IOException
See the general contract of the readChar method of DataInput (§22.1.9).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.20 public final int
readInt() throws IOException
See the general contract of the readInt method of DataInput (§22.1.10).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.21 public final long
readLong() throws IOException
See the general contract of the readLong method of DataInput (§22.1.11).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.22 public final float
readFloat() throws IOException
See the general contract of the readFloat method of DataInput (§22.1.12).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.23 public final double
readDouble() throws IOException
See the general contract of the readDouble method of DataInput (§22.1.13).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.24 public final String
readLine() throws IOException
See the general contract of the readLine method of DataInput (§22.1.14).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.25 public final String
readUTF() throws IOException
See the general contract of the readUTF method of DataInput (§22.1.15).
Bytes for this operation are read from the random access file, starting at the current file pointer.
22.23.26 public void
write(int b) throws IOException;
See the general contract of the write method of DataOutput (§22.2.1).
The byte for this operation is written to the random access file, starting at the current file pointer.
22.23.27 public void
write(byte[] b)
throws IOException, NullPointerException
See the general contract of the write method of DataOutput (§22.2.2).
Bytes for this operation are written to the random access file, starting at the current file pointer.
22.23.28 public void
write(byte[] b, int off, int len)
throws IOException, NullPointerException, IndexOutOfBoundsException
See the general contract of the write method of DataOutput (§22.2.3).
Bytes for this operation are written to the random access file, starting at the current file pointer.
22.23.29 public final void
writeBoolean(boolean v)
throws IOException
See the general contract of the writeBoolean method of DataOutput (§22.2.4).
The byte for this operation is written to the random access file, starting at the current file pointer.
22.23.30 public final void
writeByte(int v) throws IOException
See the general contract of the writeByte method of DataOutput (§22.2.5).
The byte for this operation is written to the random access file, starting at the current file pointer.
22.23.31 public final void
writeShort(int v) throws IOException
See the general contract of the writeShort method of DataOutput (§22.2.6).
Bytes for this operation are written to the random access file, starting at the current file pointer.
22.23.32 public final void
writeChar(int v) throws IOException
See the general contract of the writeChar method of DataOutput (§22.2.7).
Bytes for this operation are written to the random access file, starting at the current file pointer.
22.23.33 public final void
writeInt(int v) throws IOException
See the general contract of the writeInt method of DataOutput (§22.2.8).
Bytes for this operation are written to the random access file, starting at the current file pointer.
22.23.34 public final void
writeLong(long v) throws IOException
See the general contract of the writeLong method of DataOutput (§22.2.9).
Bytes for this operation are written to the random access file, starting at the current file pointer.
22.23.35 public final void
writeFloat(float v) throws IOException
See the general contract of the writeFloat method of DataOutput (§22.2.10).
Bytes for this operation are written to the random access file, starting at the current file pointer.
22.23.36 public final void
writeDouble(double v)
throws IOException
See the general contract of the writeDouble method of DataOutput (§22.2.11).
Bytes for this operation are written to the random access file, starting at the current file pointer.
22.23.37 public final void
writeBytes(String s) throws IOException
See the general contract of the writeBytes method of DataOutput (§22.2.12).
Bytes for this operation are written to the random access file, starting at the current file pointer.
22.23.38 public final void
writeChars(String s) throws IOException
See the general contract of the writeChars method of DataOutput (§22.2.13).
Bytes for this operation are written to the random access file, starting at the current file pointer.
22.23.39 public final void
writeUTF(String str) throws IOException
See the general contract of the writeUTF method of DataOutput (§22.2.14).
Bytes for this operation are written to the random access file, starting at the current file pointer.
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Java Language Specification (HTML generated by Suzette Pelouch on February 24, 1998)
Copyright © 1996 Sun Microsystems, Inc.
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