The java.io.Reader Class
You use a reader almost exactly as you use an input stream. Rather
than reading bytes, you read characters. The basic
read()
method reads a specified number of
characters from the underlying input stream into an array starting at
a given offset:
public abstract int read(char[] buffer, int offset, int length) throws IOException
This read()
method returns the number of
characters actually read. As with input streams reading bytes, there
may not be as many characters available as you requested. Also like
the read()
method of an input stream, it returns
-1 when it detects the end of the data.
This read()
method is abstract. Concrete
subclasses that read bytes from some source must override this
method. An IOException
may be thrown if the
underlying stream’s read()
method throws an
IOException
or an encoding error is detected.
You can also fill an array with characters using this method:
public int read(char[] buffer) throws IOException
This is equivalent to invoking read(buffer,
0,
buffer.length)
. Thus, it
also returns the number of characters read and throws an
IOException
when the underlying stream throws an
IOException
or when an encoding error is detected.
The following method reads a single character and returns it:
public int read() throws IOException
Although an int
is returned, this
int
is always between
and 65,535 and may be cast to a char
without
losing information. All three read()
methods block until some input is available, an I/O error occurs, or the end ...
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