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## java.io
Class PrintWriter

    java.lang.Object
      |
      +--java.io.Writer
            |
            +--java.io.PrintWriter

public class PrintWriter
extends Writer

Print 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() methods is invoked, rather than whenever a newline character happens to be output. The println() methods use the platform's own notion of line separator rather than the newline character.

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

Since:
  JDK1.1

Field Summary
`protected Writer` | `out` The underlying character-output stream of this `PrintWriter`.

Fields inherited from class java.io.Writer
`lock`

Constructor Summary
`PrintWriter(OutputStream out)` Create a new PrintWriter, without automatic line flushing, from an existing OutputStream.
`PrintWriter(OutputStream out, boolean autoFlush)` Create a new PrintWriter from an existing OutputStream.
`PrintWriter(Writer out)` Create a new PrintWriter, without automatic line flushing.
`PrintWriter(Writer out, boolean autoFlush)` Create a new PrintWriter.

Method Summary
`boolean` | `checkError()` Flush the stream if it's not closed and check its error state.
`void` | `close()` Close the stream.
`void` | `flush()` Flush the stream.
`void` | `print(boolean b)` Print a boolean value.
`void` | `print(char c)` Print a character.
`void` | `print(char[] s)` Print an array of characters.
`void` | `print(double d)` Print a double-precision floating-point number.
`void` | `print(float f)` Print a floating-point number.
`void` | `print(int i)` Print an integer.
`void` | `print(long l)` Print a long integer.
`void` | `print(Object obj)` Print an object.
`void` | `print(String s)` Print a string.
`void` | `println()` Terminate the current line by writing the line separator string.
`void` | `println(boolean x)` Print a boolean value and then terminate the line.
`void` | `println(char x)` Print a character and then terminate the line.
`void` | `println(char[] x)` Print an array of characters and then terminate the line.
`void` | `println(double x)` Print a double-precision floating-point number and then terminate the line.
`void` | `println(float x)` Print a floating-point number and then terminate the line.
`void` | `println(int x)` Print an integer and then terminate the line.
`void` | `println(long x)` Print a long integer and then terminate the line.
`void` | `println(Object x)` Print an Object and then terminate the line.
`void` | `println(String x)` Print a String and then terminate the line.
`protected void` | `setError()` Indicate that an error has occurred.
`void` | `write(char[] buf)` Write an array of characters.
`void` | `write(char[] buf, int off, int len)` Write a portion of an array of characters.
`void` | `write(int c)` Write a single character.
`void` | `write(String s)` Write a string.
`void` | `write(String s, int off, int len)` Write a portion of a string.

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

Field Detail

### out

    protected Writer out

  The underlying character-output stream of this `PrintWriter`.

  Since:
    1.2

Constructor Detail

### PrintWriter

    public PrintWriter(Writer out)

  Create a new PrintWriter, without automatic line flushing.

Parameters:
  `out` - A character-output stream

### PrintWriter

    public PrintWriter(Writer out,
                       boolean autoFlush)

  Create a new PrintWriter.

Parameters:
  `out` - A character-output stream
  `autoFlush` - A boolean; if true, the println() methods will flush the output buffer

### PrintWriter

    public PrintWriter(OutputStream out)

  Create 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
See Also:
  `OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)`

### PrintWriter

    public PrintWriter(OutputStream out,
                       boolean autoFlush)

  Create 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() methods will flush the output buffer
See Also:
  `OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)`

Method Detail

### flush

    public void flush()

  Flush the stream.

  Specified by:
    `flush` in class `Writer`
  See Also:
    `checkError()`

### close

    public void close()

  Close the stream.

  Specified by:
    `close` in class `Writer`
  See Also:
    `checkError()`

### checkError

    public boolean checkError()

  Flush the stream if it's not closed and check its error state. Errors are cumulative; once the stream encounters an error, this routine will return true on all successive calls.

  Returns:
    True if the print stream has encountered an error, either on the underlying output stream or during a format conversion.

### setError

    protected void setError()

  Indicate that an error has occurred.

### write

    public void write(int c)

  Write a single character.

  Overrides:
    `write` in class `Writer`
  Parameters:
    `c` - int specifying a character to be written.

### write

    public void write(char[] buf,
                      int off,
                      int len)

  Write a portion of an array of characters.

  Specified by:
    `write` in class `Writer`
  Parameters:
    `buf` - Array of characters
    `off` - Offset from which to start writing characters
    `len` - Number of characters to write

### write

    public void write(char[] buf)

  Write an array of characters. This method cannot be inherited from the Writer class because it must suppress I/O exceptions.

  Overrides:
    `write` in class `Writer`
  Parameters:
    `buf` - Array of characters to be written

### write

    public void write(String s,
                      int off,
                      int len)

  Write a portion of a string.

  Overrides:
    `write` in class `Writer`
  Parameters:
    `s` - A String
    `off` - Offset from which to start writing characters
    `len` - Number of characters to write

### write

    public void write(String s)

  Write a string. This method cannot be inherited from the Writer class because it must suppress I/O exceptions.

  Overrides:
    `write` in class `Writer`
  Parameters:
    `s` - String to be written

### print

    public void print(boolean b)

  Print a boolean value. The string produced by ``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.

  Parameters:
    `b` - The `boolean` to be printed

### print

    public void print(char c)

  Print 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.

  Parameters:
    `c` - The `char` to be printed

### print

    public void print(int i)

  Print an integer. The string produced by ``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.

  Parameters:
    `i` - The `int` to be printed
  See Also:
    `Integer.toString(int)`

### print

    public void print(long l)

  Print a long integer. The string produced by ``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.

  Parameters:
    `l` - The `long` to be printed
  See Also:
    `Long.toString(long)`

### print

    public void print(float f)

  Print a floating-point number. The string produced by ``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.

  Parameters:
    `f` - The `float` to be printed
  See Also:
    `Float.toString(float)`

### print

    public void print(double d)

  Print a double-precision floating-point number. The string produced by ``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.

  Parameters:
    `d` - The `double` to be printed
  See Also:
    `Double.toString(double)`

### print

    public void print(char[] s)

  Print 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.

  Parameters:
    `s` - The array of chars to be printed
  Throws:
    `NullPointerException` - If `s` is `null`

### print

    public void print(String s)

  Print 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.

  Parameters:
    `s` - The `String` to be printed

### print

    public void print(Object obj)

  Print an object. The string produced by the ``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.

  Parameters:
    `obj` - The `Object` to be printed
  See Also:
    `Object.toString()`

### println

    public void println()

  Terminate 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'`).

### println

    public void println(boolean x)

  Print a boolean value and then terminate the line. This method behaves as though it invokes ``print(boolean)`` and then ``println()``.

  Parameters:
    `x` - the `boolean` value to be printed

### println

    public void println(char x)

  Print a character and then terminate the line. This method behaves as though it invokes ``print(char)`` and then ``println()``.

  Parameters:
    `x` - the `char` value to be printed

### println

    public void println(int x)

  Print an integer and then terminate the line. This method behaves as though it invokes ``print(int)`` and then ``println()``.

  Parameters:
    `x` - the `int` value to be printed

### println

    public void println(long x)

  Print a long integer and then terminate the line. This method behaves as though it invokes ``print(long)`` and then ``println()``.

  Parameters:
    `x` - the `long` value to be printed

### println

    public void println(float x)

  Print a floating-point number and then terminate the line. This method behaves as though it invokes ``print(float)`` and then ``println()``.

  Parameters:
    `x` - the `float` value to be printed

### println

    public void println(double x)

  Print a double-precision floating-point number and then terminate the line. This method behaves as though it invokes ``print(double)`` and then ``println()``.

  Parameters:
    `x` - the `double` value to be printed

### println

    public void println(char[] x)

  Print an array of characters and then terminate the line. This method behaves as though it invokes ``print(char[])`` and then ``println()``.

  Parameters:
    `x` - the array of `char` values to be printed

### println

    public void println(String x)

  Print a String and then terminate the line. This method behaves as though it invokes ``print(String)`` and then ``println()``.

  Parameters:
    `x` - the `String` value to be printed

### println

    public void println(Object x)

  Print an Object and then terminate the line. This method behaves as though it invokes ``print(Object)`` and then ``println()``.

  Parameters:
    `x` - the `Object` value to be printed

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