- java.lang.Object
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- java.io.Writer
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- java.io.PrintWriter
 
 
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- All Implemented Interfaces:
- Closeable,- Flushable,- Appendable,- AutoCloseable
 
 public class PrintWriter extends Writer Prints formatted representations of objects to a text-output stream. This class implements all of theprintmethods found inPrintStream. It does not contain methods for writing raw bytes, for which a program should use unencoded byte streams.Unlike the PrintStreamclass, if automatic flushing is enabled it will be done only when one of theprintln,printf, orformatmethods 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().This class always replaces malformed and unmappable character sequences with the charset's default replacement string. The CharsetEncoder class should be used when more control over the encoding process is required. - Since:
- 1.1
 
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Constructor SummaryConstructors Constructor Description PrintWriter(File file)Creates a new PrintWriter, without automatic line flushing, with the specified file.PrintWriter(File file, String csn)Creates a new PrintWriter, without automatic line flushing, with the specified file and charset.PrintWriter(File file, Charset charset)Creates a new PrintWriter, without automatic line flushing, with the specified file and charset.PrintWriter(OutputStream out)Creates a new PrintWriter, without automatic line flushing, from an existing OutputStream.PrintWriter(OutputStream out, boolean autoFlush)Creates a new PrintWriter from an existing OutputStream.PrintWriter(OutputStream out, boolean autoFlush, Charset charset)Creates a new PrintWriter from an existing OutputStream.PrintWriter(Writer out)Creates a new PrintWriter, without automatic line flushing.PrintWriter(Writer out, boolean autoFlush)Creates a new PrintWriter.PrintWriter(String fileName)Creates a new PrintWriter, without automatic line flushing, with the specified file name.PrintWriter(String fileName, String csn)Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset.PrintWriter(String fileName, Charset charset)Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset.
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Method SummaryAll Methods Instance Methods Concrete Methods Modifier and Type Method Description PrintWriterappend(char c)Appends the specified character to this writer.PrintWriterappend(CharSequence csq)Appends the specified character sequence to this writer.PrintWriterappend(CharSequence csq, int start, int end)Appends a subsequence of the specified character sequence to this writer.booleancheckError()Flushes the stream if it's not closed and checks its error state.protected voidclearError()Clears the error state of this stream.voidclose()Closes the stream and releases any system resources associated with it.voidflush()Flushes the stream.PrintWriterformat(String format, Object... args)Writes a formatted string to this writer using the specified format string and arguments.PrintWriterformat(Locale l, String format, Object... args)Writes a formatted string to this writer using the specified format string and arguments.voidprint(boolean b)Prints a boolean value.voidprint(char c)Prints a character.voidprint(char[] s)Prints an array of characters.voidprint(double d)Prints a double-precision floating-point number.voidprint(float f)Prints a floating-point number.voidprint(int i)Prints an integer.voidprint(long l)Prints a long integer.voidprint(Object obj)Prints an object.voidprint(String s)Prints a string.PrintWriterprintf(String format, Object... args)A convenience method to write a formatted string to this writer using the specified format string and arguments.PrintWriterprintf(Locale l, String format, Object... args)A convenience method to write a formatted string to this writer using the specified format string and arguments.voidprintln()Terminates the current line by writing the line separator string.voidprintln(boolean x)Prints a boolean value and then terminates the line.voidprintln(char x)Prints a character and then terminates the line.voidprintln(char[] x)Prints an array of characters and then terminates the line.voidprintln(double x)Prints a double-precision floating-point number and then terminates the line.voidprintln(float x)Prints a floating-point number and then terminates the line.voidprintln(int x)Prints an integer and then terminates the line.voidprintln(long x)Prints a long integer and then terminates the line.voidprintln(Object x)Prints an Object and then terminates the line.voidprintln(String x)Prints a String and then terminates the line.protected voidsetError()Indicates that an error has occurred.voidwrite(char[] buf)Writes an array of characters.voidwrite(char[] buf, int off, int len)Writes A Portion of an array of characters.voidwrite(int c)Writes a single character.voidwrite(String s)Writes a string.voidwrite(String s, int off, int len)Writes a portion of a string.- 
Methods declared in class java.io.WriternullWriter
 
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Field Detail- 
outprotected Writer out The underlying character-output stream of thisPrintWriter.- Since:
- 1.2
 
 
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Constructor Detail- 
PrintWriterpublic PrintWriter(Writer out) Creates a new PrintWriter, without automatic line flushing.- Parameters:
- out- A character-output stream
 
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PrintWriterpublic PrintWriter(Writer out, boolean autoFlush) Creates a new PrintWriter.- Parameters:
- out- A character-output stream
- autoFlush- A boolean; if true, the- println,- printf, or- formatmethods will flush the output buffer
 
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PrintWriterpublic 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
- See Also:
- OutputStreamWriter(java.io.OutputStream)
 
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PrintWriterpublic 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- formatmethods will flush the output buffer
- See Also:
- OutputStreamWriter(java.io.OutputStream)
 
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PrintWriterpublic PrintWriter(OutputStream out, boolean autoFlush, Charset charset) Creates a new PrintWriter from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the specified charset.- Parameters:
- out- An output stream
- autoFlush- A boolean; if true, the- println,- printf, or- formatmethods will flush the output buffer
- charset- A charset
- Since:
- 10
 
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PrintWriterpublic PrintWriter(String fileName) throws FileNotFoundException Creates a new PrintWriter, without automatic line flushing, with the specified file name. This convenience constructor creates the necessary intermediateOutputStreamWriter, which will encode characters using the 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
 
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PrintWriterpublic 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 intermediateOutputStreamWriter, 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 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
 
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PrintWriterpublic PrintWriter(String fileName, Charset charset) throws IOException Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset. This convenience constructor creates the necessary intermediateOutputStreamWriter, 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.
- charset- A charset
- Throws:
- IOException- if an I/O 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:
- 10
 
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PrintWriterpublic PrintWriter(File file) throws FileNotFoundException Creates a new PrintWriter, without automatic line flushing, with the specified file. This convenience constructor creates the necessary intermediateOutputStreamWriter, which will encode characters using the 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
 
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PrintWriterpublic 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 intermediateOutputStreamWriter, 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 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
 
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PrintWriterpublic PrintWriter(File file, Charset charset) throws IOException Creates a new PrintWriter, without automatic line flushing, with the specified file and charset. This convenience constructor creates the necessary intermediateOutputStreamWriter, 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.
- charset- A charset
- Throws:
- IOException- if an I/O 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:
- 10
 
 
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Method Detail- 
flushpublic void flush() Flushes the stream.- Specified by:
- flushin interface- Flushable
- Specified by:
- flushin class- Writer
- See Also:
- checkError()
 
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closepublic void close() Closes the stream and releases any system resources associated with it. Closing a previously closed stream has no effect.- Specified by:
- closein interface- AutoCloseable
- Specified by:
- closein interface- Closeable
- Specified by:
- closein class- Writer
- See Also:
- checkError()
 
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checkErrorpublic boolean checkError() Flushes the stream if it's not closed and checks its error state.- Returns:
- trueif the print stream has encountered an error, either on the underlying output stream or during a format conversion.
 
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setErrorprotected void setError() Indicates that an error has occurred.This method will cause subsequent invocations of checkError()to returntrueuntilclearError()is invoked.
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clearErrorprotected void clearError() Clears the error state of this stream.This method will cause subsequent invocations of checkError()to returnfalseuntil another write operation fails and invokessetError().- Since:
- 1.6
 
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writepublic void write(int c) Writes a single character.
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writepublic void write(char[] buf, int off, int len)Writes A Portion of an array of characters.- Specified by:
- writein class- Writer
- Parameters:
- buf- Array of characters
- off- Offset from which to start writing characters
- len- Number of characters to write
- Throws:
- IndexOutOfBoundsException- If the values of the- offand- lenparameters cause the corresponding method of the underlying- Writerto throw an- IndexOutOfBoundsException
 
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writepublic 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.
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writepublic void write(String s, int off, int len) Writes a portion of a string.- Overrides:
- writein class- Writer
- Parameters:
- s- A String
- off- Offset from which to start writing characters
- len- Number of characters to write
- Throws:
- IndexOutOfBoundsException- If the values of the- offand- lenparameters cause the corresponding method of the underlying- Writerto throw an- IndexOutOfBoundsException
 
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writepublic void write(String s) Writes a string. This method cannot be inherited from the Writer class because it must suppress I/O exceptions.
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printpublic void print(boolean b) Prints a boolean value. The string produced byString.valueOf(boolean)is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
- b- The- booleanto be printed
 
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printpublic 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 thewrite(int)method.- Parameters:
- c- The- charto be printed
 
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printpublic void print(int i) Prints an integer. The string produced byString.valueOf(int)is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
- i- The- intto be printed
- See Also:
- Integer.toString(int)
 
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printpublic void print(long l) Prints a long integer. The string produced byString.valueOf(long)is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
- l- The- longto be printed
- See Also:
- Long.toString(long)
 
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printpublic void print(float f) Prints a floating-point number. The string produced byString.valueOf(float)is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
- f- The- floatto be printed
- See Also:
- Float.toString(float)
 
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printpublic void print(double d) Prints a double-precision floating-point number. The string produced byString.valueOf(double)is translated into bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
- d- The- doubleto be printed
- See Also:
- Double.toString(double)
 
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printpublic 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 thewrite(int)method.- Parameters:
- s- The array of chars to be printed
- Throws:
- NullPointerException- If- sis- null
 
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printpublic void print(String s) Prints a string. If the argument isnullthen 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 thewrite(int)method.- Parameters:
- s- The- Stringto be printed
 
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printpublic void print(Object obj) Prints an object. The string produced by theString.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 thewrite(int)method.- Parameters:
- obj- The- Objectto be printed
- See Also:
- Object.toString()
 
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printlnpublic void println() Terminates the current line by writing the line separator string. The line separator string is defined by the system propertyline.separator, and is not necessarily a single newline character ('\n').
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printlnpublic void println(boolean x) Prints a boolean value and then terminates the line. This method behaves as though it invokesprint(boolean)and thenprintln().- Parameters:
- x- the- booleanvalue to be printed
 
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printlnpublic void println(char x) Prints a character and then terminates the line. This method behaves as though it invokesprint(char)and thenprintln().- Parameters:
- x- the- charvalue to be printed
 
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printlnpublic void println(int x) Prints an integer and then terminates the line. This method behaves as though it invokesprint(int)and thenprintln().- Parameters:
- x- the- intvalue to be printed
 
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printlnpublic void println(long x) Prints a long integer and then terminates the line. This method behaves as though it invokesprint(long)and thenprintln().- Parameters:
- x- the- longvalue to be printed
 
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printlnpublic void println(float x) Prints a floating-point number and then terminates the line. This method behaves as though it invokesprint(float)and thenprintln().- Parameters:
- x- the- floatvalue to be printed
 
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printlnpublic void println(double x) Prints a double-precision floating-point number and then terminates the line. This method behaves as though it invokesprint(double)and thenprintln().- Parameters:
- x- the- doublevalue to be printed
 
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printlnpublic void println(char[] x) Prints an array of characters and then terminates the line. This method behaves as though it invokesprint(char[])and thenprintln().- Parameters:
- x- the array of- charvalues to be printed
 
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printlnpublic void println(String x) Prints a String and then terminates the line. This method behaves as though it invokesprint(String)and thenprintln().- Parameters:
- x- the- Stringvalue to be printed
 
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printlnpublic 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 invokesprint(String)and thenprintln().- Parameters:
- x- The- Objectto be printed.
 
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printfpublic 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 invocationout.format(format, args)- Parameters:
- format- A format string as described in Format string syntax.
- 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- nullargument depends on the conversion.
- Returns:
- This writer
- 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.
- NullPointerException- If the- formatis- null
- Since:
- 1.5
 
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printfpublic 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 invocationout.format(l, format, args)- Parameters:
- l- The locale to apply during formatting. If- lis- nullthen no localization is applied.
- format- A format string as described in Format string syntax.
- 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- nullargument depends on the conversion.
- Returns:
- This writer
- 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.
- NullPointerException- If the- formatis- null
- Since:
- 1.5
 
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formatpublic 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:
- format- A format string as described in Format string syntax.
- 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- nullargument depends on the conversion.
- Returns:
- This writer
- 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.
- NullPointerException- If the- formatis- null
- Since:
- 1.5
 
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formatpublic 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:
- l- The locale to apply during formatting. If- lis- nullthen no localization is applied.
- format- A format string as described in Format string syntax.
- 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- nullargument depends on the conversion.
- Returns:
- This writer
- 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.
- NullPointerException- If the- formatis- null
- Since:
- 1.5
 
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appendpublic 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 invocationout.write(csq.toString())Depending on the specification of toStringfor the character sequencecsq, the entire sequence may not be appended. For instance, invoking thetoStringmethod of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.- Specified by:
- appendin interface- Appendable
- Overrides:
- appendin class- Writer
- Parameters:
- csq- The character sequence to append. If- csqis- null, then the four characters- "null"are appended to this writer.
- Returns:
- This writer
- Since:
- 1.5
 
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appendpublic 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)whencsqis notnull, behaves in exactly the same way as the invocationout.write(csq.subSequence(start, end).toString())- Specified by:
- appendin interface- Appendable
- Overrides:
- appendin class- Writer
- Parameters:
- csq- The character sequence from which a subsequence will be appended. If- csqis- null, then characters will be appended as if- csqcontained the four characters- "null".
- start- The index of the first character in the subsequence
- end- The index of the character following the last character in the subsequence
- Returns:
- This writer
- Throws:
- IndexOutOfBoundsException- If- startor- endare negative,- startis greater than- end, or- endis greater than- csq.length()
- Since:
- 1.5
 
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appendpublic 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 invocationout.write(c)- Specified by:
- appendin interface- Appendable
- Overrides:
- appendin class- Writer
- Parameters:
- c- The 16-bit character to append
- Returns:
- This writer
- Since:
- 1.5
 
 
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