File I/O - Absolute Java - page 602

Display 10.8 Some Methods of the Class BufferedReader (part 2 of 2)

public int read() throws IOException
Reads a single character from the input stream and returns that character as an int value. If the
read goes beyond the end of the file, then -1 is returned. Note that the value is returned as an int .
To obtain a char , you must perform a type cast on the value returned. The end of a file is signaled
by returning -1 . (All of the “real” characters return a positive integer.)
public long skip( long n) throws IOException
Skips n characters.
public void close() throws IOException
Closes the stream's connection to a file.

read method

The method read reads a single character. But note that read returns a value of
type int that corresponds to the character read; it does not return the character itself.
Thus, to get the character, you must use a type cast, as in

char next = ( char )(inputStream.read());
If inputStream is in the class BufferedReader and is connected to a text file, this will
set next equal to the first character in the file that has not yet been read.
Notice that the program in Display 10.7 catches two kinds of exceptions,
FileNotFoundException and IOException . An attempt to open the file may throw
a FileNotFoundException , and any of the invocations of inputStream.readLine()
may throw an IOException . Because FileNotFoundException is a kind of
IOException , you could use only the catch block for IOException . However, if you
were to do this, then you would get less information if an exception were thrown. If you
use only one catch block and an exception is thrown, you will not know if the problem
occurred when opening the file or when reading from the file after it was opened.

Self-Test Exercises

12. Write some code that will create a stream named fileIn that is a member of
the class BufferedReader and that connects the stream to a text fi le named
joe so that your program can read input from the text fi le joe .

13. What is the type of a value returned by the method readLine in the class
BufferedReader ? What is the type of a value returned by the method read in
the class BufferedReader ?

14. Might the methods read and readLine in the class BufferedReader throw an
exception? If so, what type of exception?