This class is a character output stream
that implements a number of print(
)
and println( )
methods that output textual representations of primitive values and
objects. When you create a PrintWriter object, you
specify a character or byte output stream that it should write its
characters to and, optionally, whether the
PrintWriter stream should be automatically flushed
whenever println( ) is called. If you specify a
byte output stream as the destination, the PrintWriter(
) constructor automatically creates the necessary
OutputStreamWriter object to convert characters to
bytes using the default encoding. In Java 5.0, convenience constructors allow
you to specify a file (either as a file name or a
File object) as the destination. You may
optionally specify the name of a charset to use for
character-to-byte conversion when writing
to the file.
PrintWriter
implements the normal write( ), flush(
), and close( ) methods all
Writer subclasses define. It is more common to use
the higher-level print( ) and println(
) methods, each of which converts its argument to a string
before outputting it. println( ) can also
terminate the line (and optionally flush the buffer) after printing
its argument. In Java 5.0, you can also use the printf(
)
methods (or the
format( ) methods that behave identically) for
formatted output. These methods behave like the format(
) method of a java.util.Formatter object
that uses the PrintWriter as its destination.
The methods of
PrintWriter never throw exceptions. Instead, when
errors occur, they set an internal flag you can check by calling
checkError( ). checkError( )
first flushes the internal stream and then returns
true if any exception has occurred while writing
values to that stream. Once an error has occurred on a
PrintWriter object, all subsequent calls to
checkError( ) return true;
there is no way to reset the error flag.
PrintWriter is the character stream analog to
PrintStream, which it supersedes. You can usually
easily replace any PrintStream objects in a
program with PrintWriter objects. This is
particularly important for internationalized programs. The only valid
remaining use for the PrintStream class is for the
System.out and System.err
standard output streams. See PrintStream for
details.
public class PrintWriter extends Writer {
// Public Constructors
5.0 public PrintWriter(String fileName) throws FileNotFoundException;
5.0 public PrintWriter(File file) throws FileNotFoundException;
public PrintWriter(OutputStream out);
public PrintWriter(Writer out);
5.0 public PrintWriter(File file, String csn) throws FileNotFoundException,
UnsupportedEncodingException;
5.0 public PrintWriter(String fileName, String csn) throws FileNotFoundException,
UnsupportedEncodingException;
public PrintWriter(OutputStream out, boolean autoFlush);
public PrintWriter(Writer out, boolean autoFlush);
// Public Instance Methods
5.0 public PrintWriter append(char c);
5.0 public PrintWriter append(CharSequence csq);
5.0 public PrintWriter append(CharSequence csq, int start, int end);
public boolean checkError( );
5.0 public PrintWriter format(String format, Object... args);
5.0 public PrintWriter format(java.util.Locale l, String format, Object... args);
public void print(double d);
public void print(float f);
public void print(long l);
public void print(Object obj);
public void print(String s);
public void print(char[ ] s);
public void print(boolean b);
public void print(char c);
public void print(int i);
5.0 public PrintWriter printf(String format, Object... args);
5.0 public PrintWriter printf(java.util.Locale l, String format, Object... args);
public void println( );
public void println(double x);
public void println(float x);
public void println(char[ ] x);
public void println(Object x);
public void println(String x);
public void println(char x);
public void println(boolean x);
public void println(long x);
public void println(int x);
// Public Methods Overriding Writer
public void close( );
public void flush( );
public void write(String s);
public void write(char[ ] buf);
public void write(int c);
public void write(String s, int off, int len);
public void write(char[ ] buf, int off, int len);
// Protected Instance Methods
protected void setError( );
// Protected Instance Fields
1.2 protected Writer out;
}
