Class: java.io.PrintWriter

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

Unlike the java.io.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().

Authors:
@author Frank Yellin
@author Mark Reinhold
Since:
@since JDK1.1

Inheritance

Superclass tree: Implements:

Methods

  • PrintWritertop

    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 default charset for this instance of the Java virtual machine.
    Parameters:
    @param 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.
    Exceptions:
    @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
    @throws SecurityException If a security manager is present and checkWrite(file.getPath()) denies write access to the file
    Since:
    @since 1.5
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  • PrintWritertop

    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:
    @param 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.
    @param csn The name of a supported charset
    Exceptions:
    @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
    @throws SecurityException If a security manager is present and checkWrite(file.getPath()) denies write access to the file
    @throws UnsupportedEncodingException If the named charset is not supported
    Since:
    @since 1.5
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  • PrintWritertop

    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:
    @param out An output stream
    See:
    @see java.io.OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)
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  • PrintWritertop

    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:
    @param out An output stream
    @param autoFlush A boolean; if true, the println, printf, or format methods will flush the output buffer
    See:
    @see java.io.OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)
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  • PrintWritertop

    public PrintWriter(Writer out)
    Creates a new PrintWriter, without automatic line flushing.
    Parameters:
    @param out A character-output stream
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  • PrintWritertop

    public PrintWriter(Writer out, boolean autoFlush)
    Creates a new PrintWriter.
    Parameters:
    @param out A character-output stream
    @param autoFlush A boolean; if true, the println, printf, or format methods will flush the output buffer
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  • PrintWritertop

    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 default charset for this instance of the Java virtual machine.
    Parameters:
    @param 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.
    Exceptions:
    @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
    @throws SecurityException If a security manager is present and checkWrite(fileName) denies write access to the file
    Since:
    @since 1.5
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  • PrintWritertop

    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:
    @param 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.
    @param csn The name of a supported charset
    Exceptions:
    @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
    @throws SecurityException If a security manager is present and checkWrite(fileName) denies write access to the file
    @throws UnsupportedEncodingException If the named charset is not supported
    Since:
    @since 1.5
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  • appendtop

    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)
    Parameters:
    @param c The 16-bit character to append
    Return:
    @return This writer
    Since:
    @since 1.5
    Specified by:
    append from Appendable
    Override hierarchy:
    append from Writer
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  • appendtop

    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.

    Parameters:
    @param csq The character sequence to append. If csq is null, then the four characters "null" are appended to this writer.
    Return:
    @return This writer
    Since:
    @since 1.5
    Specified by:
    append from Appendable
    Override hierarchy:
    append from Writer
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  • appendtop

    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())
    Parameters:
    @param csq The character sequence from which a subsequence will be appended. If csq is null, then characters will be appended as if csq contained the four characters "null".
    @param start The index of the first character in the subsequence
    @param end The index of the character following the last character in the subsequence
    Return:
    @return This writer
    Exceptions:
    @throws IndexOutOfBoundsException If start or end are negative, start is greater than end, or end is greater than csq.length()
    Since:
    @since 1.5
    Specified by:
    append from Appendable
    Override hierarchy:
    append from Writer
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  • checkErrortop

    public boolean checkError()
    Flushes the stream if it's not closed and checks its error state.
    Return:
    @return true if the print stream has encountered an error, either on the underlying output stream or during a format conversion.
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  • clearErrortop

    protected void clearError()
    Clears the error state of this stream.

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

    Since:
    @since 1.6
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  • closetop

    public void close()
    Closes the stream and releases any system resources associated with it. Closing a previously closed stream has no effect.
    See:
    @see java.io.PrintWriter.checkError()
    Specified by:
    close from Closeable
    Override hierarchy:
    close from Writer
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  • flushtop

    public void flush()
    Flushes the stream.
    See:
    @see java.io.PrintWriter.checkError()
    Specified by:
    flush from Flushable
    Override hierarchy:
    flush from Writer
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  • formattop

    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.

    Parameters:
    @param format A format string as described in Format string syntax.
    @param args Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
    Return:
    @return This writer
    Exceptions:
    @throws IllegalFormatException If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the Formatter class specification.
    @throws NullPointerException If the format is null
    Since:
    @since 1.5
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  • formattop

    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.
    Parameters:
    @param l The locale to apply during formatting. If l is null then no localization is applied.
    @param format A format string as described in Format string syntax.
    @param args Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
    Return:
    @return This writer
    Exceptions:
    @throws IllegalFormatException If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.
    @throws NullPointerException If the format is null
    Since:
    @since 1.5
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  • printtop

    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 java.io.PrintWriter.write(int) method.
    Parameters:
    @param c The char to be printed
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  • printtop

    public void print(double d)
    Prints 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 java.io.PrintWriter.write(int) method.
    Parameters:
    @param d The double to be printed
    See:
    @see Double.toString(double)
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  • printtop

    public void print(float f)
    Prints 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 java.io.PrintWriter.write(int) method.
    Parameters:
    @param f The float to be printed
    See:
    @see Float.toString(float)
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  • printtop

    public void print(int i)
    Prints 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 java.io.PrintWriter.write(int) method.
    Parameters:
    @param i The int to be printed
    See:
    @see Integer.toString(int)
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  • printtop

    public void print(long l)
    Prints 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 java.io.PrintWriter.write(int) method.
    Parameters:
    @param l The long to be printed
    See:
    @see Long.toString(long)
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  • printtop

    public void print(Object obj)
    Prints an object. The string produced by the String.valueOf(java.lang.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 java.io.PrintWriter.write(int) method.
    Parameters:
    @param obj The Object to be printed
    See:
    @see Object.toString()
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  • printtop

    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 java.io.PrintWriter.write(int) method.
    Parameters:
    @param s The String to be printed
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  • printtop

    public void print(boolean b)
    Prints 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 java.io.PrintWriter.write(int) method.
    Parameters:
    @param b The boolean to be printed
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  • printtop

    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 java.io.PrintWriter.write(int) method.
    Parameters:
    @param s The array of chars to be printed
    Exceptions:
    @throws NullPointerException If s is null
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  • printftop

    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)
    Parameters:
    @param format A format string as described in Format string syntax.
    @param args Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
    Return:
    @return This writer
    Exceptions:
    @throws IllegalFormatException If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.
    @throws NullPointerException If the format is null
    Since:
    @since 1.5
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  • printftop

    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)
    Parameters:
    @param l The locale to apply during formatting. If l is null then no localization is applied.
    @param format A format string as described in Format string syntax.
    @param args Arguments referenced by the format specifiers in the format string. If there are more arguments than format specifiers, the extra arguments are ignored. The number of arguments is variable and may be zero. The maximum number of arguments is limited by the maximum dimension of a Java array as defined by the Java Virtual Machine Specification. The behaviour on a null argument depends on the conversion.
    Return:
    @return This writer
    Exceptions:
    @throws IllegalFormatException If a format string contains an illegal syntax, a format specifier that is incompatible with the given arguments, insufficient arguments given the format string, or other illegal conditions. For specification of all possible formatting errors, see the Details section of the formatter class specification.
    @throws NullPointerException If the format is null
    Since:
    @since 1.5
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  • printlntop

    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').
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  • printlntop

    public void println(char x)
    Prints a character and then terminates the line. This method behaves as though it invokes java.io.PrintWriter.print(char) and then java.io.PrintWriter.println().
    Parameters:
    @param x the char value to be printed
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  • printlntop

    public void println(double x)
    Prints a double-precision floating-point number and then terminates the line. This method behaves as though it invokes java.io.PrintWriter.print(double) and then java.io.PrintWriter.println().
    Parameters:
    @param x the double value to be printed
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  • printlntop

    public void println(float x)
    Prints a floating-point number and then terminates the line. This method behaves as though it invokes java.io.PrintWriter.print(float) and then java.io.PrintWriter.println().
    Parameters:
    @param x the float value to be printed
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  • printlntop

    public void println(int x)
    Prints an integer and then terminates the line. This method behaves as though it invokes java.io.PrintWriter.print(int) and then java.io.PrintWriter.println().
    Parameters:
    @param x the int value to be printed
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  • printlntop

    public void println(long x)
    Prints a long integer and then terminates the line. This method behaves as though it invokes java.io.PrintWriter.print(long) and then java.io.PrintWriter.println().
    Parameters:
    @param x the long value to be printed
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  • printlntop

    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 java.io.PrintWriter.print(java.lang.String) and then java.io.PrintWriter.println().
    Parameters:
    @param x The Object to be printed.
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  • printlntop

    public void println(String x)
    Prints a String and then terminates the line. This method behaves as though it invokes java.io.PrintWriter.print(java.lang.String) and then java.io.PrintWriter.println().
    Parameters:
    @param x the String value to be printed
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  • printlntop

    public void println(boolean x)
    Prints a boolean value and then terminates the line. This method behaves as though it invokes java.io.PrintWriter.print(boolean) and then java.io.PrintWriter.println().
    Parameters:
    @param x the boolean value to be printed
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  • printlntop

    public void println(char[] x)
    Prints an array of characters and then terminates the line. This method behaves as though it invokes java.io.PrintWriter.print(char[]) and then java.io.PrintWriter.println().
    Parameters:
    @param x the array of char values to be printed
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  • setErrortop

    protected void setError()
    Indicates that an error has occurred.

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

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  • writetop

    public void write(int c)
    Writes a single character.
    Parameters:
    @param c int specifying a character to be written.
    Override hierarchy:
    write from Writer
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  • writetop

    public void write(String s)
    Writes a string. This method cannot be inherited from the Writer class because it must suppress I/O exceptions.
    Parameters:
    @param s String to be written
    Override hierarchy:
    write from Writer
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  • writetop

    public void write(String s, int off, int len)
    Writes a portion of a string.
    Parameters:
    @param s A String
    @param off Offset from which to start writing characters
    @param len Number of characters to write
    Override hierarchy:
    write from Writer
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  • writetop

    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.
    Parameters:
    @param buf Array of characters to be written
    Override hierarchy:
    write from Writer
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  • writetop

    public void write(char[] buf, int off, int len)
    Writes A Portion of an array of characters.
    Parameters:
    @param buf Array of characters
    @param off Offset from which to start writing characters
    @param len Number of characters to write
    Override hierarchy:
    write from Writer
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Fields

  • out

    protected Writer out
    The underlying character-output stream of this PrintWriter.