Java IO.pdf - Nguyen Dang Binh

Java I/O
Admittedly, this is a contrived example. If you really needed to do this, you could just call the
string's toCharArray() method and loop through that (or even the string itself) using its
charAt() method.
15.7 Reading and Writing Files
You've already learned how to chain an OutputStreamWriter to a FileOutputStream and
an InputStreamReader to a FileInputStream. Although this isn't hard, Java provides two
simple utility classes that take care of the details, java.io.FileWriter and
java.io.FileReader.
15.7.1 FileWriter
The FileWriter class is a subclass of OutputStreamWriter that writes text files using the
platform's default character encoding and buffer size. If you need to change these values,
construct an OutputStreamWriter on a FileOutputStream instead.
public class FileWriter extends OutputStreamWriter
This class has four constructors:
public FileWriter(String fileName) throws IOException
public FileWriter(String fileName, boolean append) throws IOException
public FileWriter(File file) throws IOException
public FileWriter(FileDescriptor fd)
The first constructor opens a file and positions the file pointer at the beginning of the file. Any
text in the file is overwritten. For example:
FileWriter fw = new FileWriter("36.html");
The second constructor allows you to specify that new text is appended to the existing
contents of the file rather than overwriting them by setting the second argument to true. For
example:
FileWriter fw = new FileWriter("36.html", true);
The third and fourth constructors use a File object and a FileDescriptor, respectively,
instead of a filename to identify the file to be written to. Any pre-existing contents in a file so
opened are overwritten.
No methods other than the constructors are declared in this class. You use the standard
Writer methods like write(), flush(), and close() to write the text in the file.
15.7.2 FileReader
The FileReader class is a subclass of InputStreamReader that reads text files using the
platform's default character encoding. If you need to change the encoding, construct an
InputStreamReader chained to a FileInputStream instead.
public class FileReader extends InputStreamReader
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