PrintWriter

PrintWriter

java.io

---

Java 1.1

appendable closeable flushable

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.

Figure 9-50. java.io.PrintWriter

 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  ;   } 

Passed To

THRowable.printStackTrace( ) , java.util.Properties.list( ) , javax.xml.transform.TransformerException.printStackTrace( ) , javax.xml.xpath.XPathException.printStackTrace( )