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desired unless the object has a properly defined toString() method. The Argument is output to the file
connected to the stream. After the Argument has been output, the line ends, and so the next output is sent
to the next line.
RandomAccessFile
Package: java.io
Object
|
+ RandomAccessFile
Implements Interfaces: DataInput, DataOutput
public RandomAccessFile(String fileName, String mode)
public RandomAccessFile(File fileObject, String mode)
Opens the file, does not delete data already in the file, but does position the file pointer at the first (zeroth)
location.
The mode must be one of the following:
"r" Open for reading only.
"rw" Open for reading and writing.
"rws" Same as "rw", and also requires that every update to the file's content or metadata be written syn-
chronously to the underlying storage device.
"rwd" Same as "rw", and also requires that every update to the file's content be written synchronously to
the underlying storage device.
"rws" and "rwd" are not covered in this book.
public void close() throws IOException
Closes the stream s connection to a file.
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Summary of Classes and Interfaces 1017
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 newLength argu-
ment, then the file will be truncated. In this case, if the file pointer location as returned by the getFile-
Pointer method is greater than newLength, then after this method returns, the file pointer location will
be equal to newLength.
If the present length of the file as returned by the length method is smaller than newLength, then the
file will be extended. In this case, the contents of the extended portion of the file are not defined.
public long getFilePointer() throws IOException
Returns the current location of the file pointer. Locations are numbered starting with 0.
public long length() throws IOException
Returns the length of the file.
public int read() throws IOException
Reads a byte of data from the file and returns it as an integer in the range 0 to 255.
public int read(byte[] a) throws IOException
Reads up to a.length bytes of data from the file into the array of bytes. Returns the total number of
bytes read or -1 if the end of the file is reached.
public final boolean readBoolean() throws IOException
Reads a boolean value from the file and returns that value. If an attempt is made to read beyond the end
of the file, an EOFException is thrown.
public final byte readByte() throws IOException
Reads a byte value from the file and returns that value. If an attempt is made to read beyond the end of
the file, an EOFException is thrown.
public final char readChar() throws IOException
Reads a char value from the file and returns that value. If an attempt is made to read beyond the end of
the file, an EOFException is thrown.
public final double readDouble() throws IOException
Reads a double value from the file and returns that value. If an attempt is made to read beyond the end
of the file, an EOFException is thrown.
public final float readFloat() throws IOException
Reads a float value from the file and returns that value. If an attempt is made to read beyond the end of
the file, an EOFException is thrown.
public final int readInt() throws IOException
Reads an int value from the file and returns that value. If an attempt is made to read beyond the end of
the file, an EOFException is thrown.
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1018 Appendix 4 Summary of Classes and Interfaces
public final long readLong() throws IOException
Reads a long value from the file and returns that value. If an attempt is made to read beyond the end of
the file, an EOFException is thrown.
public final short readShort() throws IOException
Reads a short value from the file and returns that value. If an attempt is made to read beyond the end of
the file, an EOFException is thrown.
public final String readUTF() throws IOException
Reads a String value from the file and returns that value. If an attempt is made to read beyond the end of
the file, an EOFException is thrown.
public void seek(long location) throws IOException
Moves the file pointer to the specified location.
public void write(byte[] a) throws IOException
Writes a.length bytes from the specified byte array to the file.
public void write(int b) throws IOException
Writes the specified byte to the file.
public final void writeBoolean(boolean b) throws IOException
Writes the boolean b to the file.
public final void writeByte(byte b) throws IOException
Writes the byte b to the file.
public final void writeChar(char c) throws IOException
Writes the char c to the file.
public final void writeDouble(double d) throws IOException
Writes the double d to the file.
public final void writeFloat(float f) throws IOException
Writes the float f to the file.
public final void writeInt(int n) throws IOException
Writes the int n to the file.
public final void writeLong(long n) throws IOException
Writes the long n to the file.
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Summary of Classes and Interfaces 1019
public final void writeShort(short n) throws IOException
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