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java.io
public class: PrintWriter [javadoc | source]
java.lang.Object
   java.io.Writer
      java.io.PrintWriter

All Implemented Interfaces:
    Flushable, Closeable, Appendable

Direct Known Subclasses:
    NPrintWriter

Prints formatted representations of objects to a text-output stream. This class implements all of the print methods found in PrintStream . It does not contain methods for writing raw bytes, for which a program should use unencoded byte streams.

Unlike the PrintStream class, if automatic flushing is enabled it will be done only when one of the println, printf, or format methods is invoked, rather than whenever a newline character happens to be output. These methods use the platform's own notion of line separator rather than the newline character.

Methods in this class never throw I/O exceptions, although some of its constructors may. The client may inquire as to whether any errors have occurred by invoking checkError() .

Field Summary
protected  Writer out    The underlying character-output stream of this PrintWriter.
    since: 1.2 -
 
Fields inherited from java.io.Writer:
lock
Constructor:
 public PrintWriter(Writer out) 
    Creates a new PrintWriter, without automatic line flushing.
    Parameters:
    out - A character-output stream
 public PrintWriter(OutputStream out) 
    Creates a new PrintWriter, without automatic line flushing, from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding.
    Parameters:
    out - An output stream
    Also see:
    java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream)
 public PrintWriter(String fileName) throws FileNotFoundException 
    Creates a new PrintWriter, without automatic line flushing, with the specified file name. This convenience constructor creates the necessary intermediate OutputStreamWriter , which will encode characters using the {@linkplain java.nio.charset.Charset#defaultCharset() default charset} for this instance of the Java virtual machine.
    Parameters:
    fileName - The name of the file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.
    Throws:
    FileNotFoundException - If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file
    SecurityException - If a security manager is present and checkWrite(fileName) denies write access to the file
    since: 1.5 -
 public PrintWriter(File file) throws FileNotFoundException 
    Creates a new PrintWriter, without automatic line flushing, with the specified file. This convenience constructor creates the necessary intermediate OutputStreamWriter , which will encode characters using the {@linkplain java.nio.charset.Charset#defaultCharset() default charset} for this instance of the Java virtual machine.
    Parameters:
    file - The file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.
    Throws:
    FileNotFoundException - If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file
    SecurityException - If a security manager is present and checkWrite(file.getPath()) denies write access to the file
    since: 1.5 -
 public PrintWriter(Writer out,
    boolean autoFlush) 
    Creates a new PrintWriter.
    Parameters:
    out - A character-output stream
    autoFlush - A boolean; if true, the println, printf, or format methods will flush the output buffer
 public PrintWriter(OutputStream out,
    boolean autoFlush) 
    Creates a new PrintWriter from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding.
    Parameters:
    out - An output stream
    autoFlush - A boolean; if true, the println, printf, or format methods will flush the output buffer
    Also see:
    java.io.OutputStreamWriter#OutputStreamWriter(java.io.OutputStream)
 public PrintWriter(String fileName,
    String csn) throws FileNotFoundException, UnsupportedEncodingException 
    Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset. This convenience constructor creates the necessary intermediate OutputStreamWriter , which will encode characters using the provided charset.
    Parameters:
    fileName - The name of the file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.
    csn - The name of a supported {@linkplain java.nio.charset.Charset charset}
    Throws:
    FileNotFoundException - If the given string does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file
    SecurityException - If a security manager is present and checkWrite(fileName) denies write access to the file
    UnsupportedEncodingException - If the named charset is not supported
    since: 1.5 -
 public PrintWriter(File file,
    String csn) throws FileNotFoundException, UnsupportedEncodingException 
    Creates a new PrintWriter, without automatic line flushing, with the specified file and charset. This convenience constructor creates the necessary intermediate OutputStreamWriter , which will encode characters using the provided charset.
    Parameters:
    file - The file to use as the destination of this writer. If the file exists then it will be truncated to zero size; otherwise, a new file will be created. The output will be written to the file and is buffered.
    csn - The name of a supported {@linkplain java.nio.charset.Charset charset}
    Throws:
    FileNotFoundException - If the given file object does not denote an existing, writable regular file and a new regular file of that name cannot be created, or if some other error occurs while opening or creating the file
    SecurityException - If a security manager is present and checkWrite(file.getPath()) denies write access to the file
    UnsupportedEncodingException - If the named charset is not supported
    since: 1.5 -
Method from java.io.PrintWriter Summary:
append,   append,   append,   checkError,   clearError,   close,   flush,   format,   format,   print,   print,   print,   print,   print,   print,   print,   print,   print,   printf,   printf,   println,   println,   println,   println,   println,   println,   println,   println,   println,   println,   setError,   write,   write,   write,   write,   write
Methods from java.io.Writer:
append,   append,   append,   close,   flush,   write,   write,   write,   write,   write
Methods from java.lang.Object:
clone,   equals,   finalize,   getClass,   hashCode,   notify,   notifyAll,   toString,   wait,   wait,   wait
Method from java.io.PrintWriter Detail:
 public PrintWriter append(CharSequence csq) 
    Appends the specified character sequence to this writer.

    An invocation of this method of the form out.append(csq) behaves in exactly the same way as the invocation

        out.write(csq.toString()) 

    Depending on the specification of toString for the character sequence csq, the entire sequence may not be appended. For instance, invoking the toString method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.

 public PrintWriter append(char c) 
    Appends the specified character to this writer.

    An invocation of this method of the form out.append(c) behaves in exactly the same way as the invocation

        out.write(c) 
 public PrintWriter append(CharSequence csq,
    int start,
    int end) 
    Appends a subsequence of the specified character sequence to this writer.

    An invocation of this method of the form out.append(csq, start, end) when csq is not null, behaves in exactly the same way as the invocation

        out.write(csq.subSequence(start, end).toString()) 
 public boolean checkError() 
    Flushes the stream if it's not closed and checks its error state.
 protected  void clearError() 
    Clears the error state of this stream.

    This method will cause subsequent invocations of #checkError() to return false until another write operation fails and invokes #setError() .

 public  void close() 
    Closes the stream and releases any system resources associated with it. Closing a previously closed stream has no effect.
 public  void flush() 
    Flushes the stream.
 public PrintWriter format(String format,
    Object args) 
    Writes a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer.

    The locale always used is the one returned by Locale.getDefault() , regardless of any previous invocations of other formatting methods on this object.

 public PrintWriter format(Locale l,
    String format,
    Object args) 
    Writes a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer.
 public  void print(boolean b) 
    Prints a boolean value. The string produced by java.lang.String#valueOf(boolean) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the #write(int) method.
 public  void print(char c) 
    Prints a character. The character is translated into one or more bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the #write(int) method.
 public  void print(int i) 
    Prints an integer. The string produced by java.lang.String#valueOf(int) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the #write(int) method.
 public  void print(long l) 
    Prints a long integer. The string produced by java.lang.String#valueOf(long) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the #write(int) method.
 public  void print(float f) 
    Prints a floating-point number. The string produced by java.lang.String#valueOf(float) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the #write(int) method.
 public  void print(double d) 
    Prints a double-precision floating-point number. The string produced by java.lang.String#valueOf(double) is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the #write(int) method.
 public  void print(char[] s) 
    Prints an array of characters. The characters are converted into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the #write(int) method.
 public  void print(String s) 
    Prints a string. If the argument is null then the string "null" is printed. Otherwise, the string's characters are converted into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the #write(int) method.
 public  void print(Object obj) 
    Prints an object. The string produced by the java.lang.String#valueOf(Object) method is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the #write(int) method.
 public PrintWriter printf(String format,
    Object args) 
    A convenience method to write a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer.

    An invocation of this method of the form out.printf(format, args) behaves in exactly the same way as the invocation

        out.format(format, args) 
 public PrintWriter printf(Locale l,
    String format,
    Object args) 
    A convenience method to write a formatted string to this writer using the specified format string and arguments. If automatic flushing is enabled, calls to this method will flush the output buffer.

    An invocation of this method of the form out.printf(l, format, args) behaves in exactly the same way as the invocation

        out.format(l, format, args) 
 public  void println() 
    Terminates the current line by writing the line separator string. The line separator string is defined by the system property line.separator, and is not necessarily a single newline character ('\n').
 public  void println(boolean x) 
    Prints a boolean value and then terminates the line. This method behaves as though it invokes #print(boolean) and then #println() .
 public  void println(char x) 
    Prints a character and then terminates the line. This method behaves as though it invokes #print(char) and then #println() .
 public  void println(int x) 
    Prints an integer and then terminates the line. This method behaves as though it invokes #print(int) and then #println() .
 public  void println(long x) 
    Prints a long integer and then terminates the line. This method behaves as though it invokes #print(long) and then #println() .
 public  void println(float x) 
    Prints a floating-point number and then terminates the line. This method behaves as though it invokes #print(float) and then #println() .
 public  void println(double x) 
    Prints a double-precision floating-point number and then terminates the line. This method behaves as though it invokes #print(double) and then #println() .
 public  void println(char[] x) 
    Prints an array of characters and then terminates the line. This method behaves as though it invokes #print(char[]) and then #println() .
 public  void println(String x) 
    Prints a String and then terminates the line. This method behaves as though it invokes #print(String) and then #println() .
 public  void println(Object x) 
    Prints an Object and then terminates the line. This method calls at first String.valueOf(x) to get the printed object's string value, then behaves as though it invokes #print(String) and then #println() .
 protected  void setError() 
    Indicates that an error has occurred.

    This method will cause subsequent invocations of #checkError() to return true until #clearError() is invoked.

 public  void write(int c) 
    Writes a single character.
 public  void write(char[] buf) 
    Writes an array of characters. This method cannot be inherited from the Writer class because it must suppress I/O exceptions.
 public  void write(String s) 
    Writes a string. This method cannot be inherited from the Writer class because it must suppress I/O exceptions.
 public  void write(char[] buf,
    int off,
    int len) 
    Writes A Portion of an array of characters.
 public  void write(String s,
    int off,
    int len) 
    Writes a portion of a string.