Class PrintWriter
- All Implemented Interfaces:
Closeable,Flushable,Appendable,AutoCloseable
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().
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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Field Summary
FieldsModifier and TypeFieldDescriptionprotected WriterThe underlying character-output stream of thisPrintWriter. -
Constructor Summary
ConstructorsConstructorDescriptionPrintWriter(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. -
Method Summary
Modifier and TypeMethodDescriptionappend(char c) Appends the specified character to this writer.append(CharSequence csq) Appends the specified character sequence to this writer.append(CharSequence csq, int start, int end) Appends a subsequence of the specified character sequence to this writer.booleanFlushes the stream if it's not closed and checks its error state.protected voidClears the error state of this stream.voidclose()Closes the stream and releases any system resources associated with it.voidflush()Flushes the stream.Writes a formatted string to this writer using the specified format string and arguments.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.voidPrints an object.voidPrints a string.A convenience method to write a formatted string to this writer using the specified format string and arguments.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.voidPrints an Object and then terminates the line.voidPrints a String and then terminates the line.protected voidsetError()Sets the error state of the stream totrue.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.voidWrites a string.voidWrites a portion of a string.Methods declared in class java.io.Writer
nullWriter
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Field Details
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out
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Constructor Details
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PrintWriter
Creates a new PrintWriter, without automatic line flushing.- Parameters:
out- A character-output stream
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PrintWriter
Creates a new PrintWriter.- Parameters:
out- A character-output streamautoFlush- A boolean; if true, theprintln,printf, orformatmethods will flush the output buffer
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PrintWriter
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 charset, or whereoutis aPrintStream, the charset used by the print stream.- Parameters:
out- An output stream- See Also:
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PrintWriter
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 charset, or whereoutis aPrintStream, the charset used by the print stream.- Parameters:
out- An output streamautoFlush- A boolean; if true, theprintln,printf, orformatmethods will flush the output buffer- See Also:
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PrintWriter
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 streamautoFlush- A boolean; if true, theprintln,printf, orformatmethods will flush the output buffercharset- A charset- Since:
- 10
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PrintWriter
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- Since:
- 1.5
- See Also:
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PrintWriter
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 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 fileUnsupportedEncodingException- If the named charset is not supported- Since:
- 1.5
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PrintWriter
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- Since:
- 10
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PrintWriter
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- Since:
- 1.5
- See Also:
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PrintWriter
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 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 fileUnsupportedEncodingException- If the named charset is not supported- Since:
- 1.5
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PrintWriter
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- Since:
- 10
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Method Details
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flush
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close
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checkError
public boolean checkError()Flushes the stream if it's not closed and checks its error state.- Returns:
trueif and only if this stream has encountered anIOException, or thesetErrormethod has been invoked
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setError
protected void setError()Sets the error state of the stream totrue.This method will cause subsequent invocations of
checkError()to returntrueuntilclearError()is invoked. -
clearError
protected 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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write
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write
public void write(char[] buf, int off, int len) Writes A Portion of an array of characters.- Specified by:
writein classWriter- Parameters:
buf- Array of charactersoff- Offset from which to start writing characterslen- Number of characters to write- Throws:
IndexOutOfBoundsException- If the values of theoffandlenparameters cause the corresponding method of the underlyingWriterto throw anIndexOutOfBoundsException
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write
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write
Writes a portion of a string.- Overrides:
writein classWriter- Parameters:
s- A Stringoff- Offset from which to start writing characterslen- Number of characters to write- Throws:
IndexOutOfBoundsException- If the values of theoffandlenparameters cause the corresponding method of the underlyingWriterto throw anIndexOutOfBoundsException
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write
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print
public void print(boolean b) Prints a boolean value. The string produced byString.valueOf(boolean)is translated into bytes according to the default charset, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
b- Thebooleanto be printed- See Also:
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print
public void print(char c) Prints a character. The character is translated into one or more bytes according to the default charset, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
c- Thecharto be printed- See Also:
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print
public void print(int i) Prints an integer. The string produced byString.valueOf(int)is translated into bytes according to the default charset, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
i- Theintto be printed- See Also:
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print
public void print(long l) Prints a long integer. The string produced byString.valueOf(long)is translated into bytes according to the default charset, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
l- Thelongto be printed- See Also:
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print
public void print(float f) Prints a floating-point number. The string produced byString.valueOf(float)is translated into bytes according to the default charset, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
f- Thefloatto be printed- See Also:
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print
public void print(double d) Prints a double-precision floating-point number. The string produced byString.valueOf(double)is translated into bytes according to the default charset, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
d- Thedoubleto be printed- See Also:
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print
public void print(char[] s) Prints an array of characters. The characters are converted into bytes according to the default charset, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
s- The array of chars to be printed- Throws:
NullPointerException- Ifsisnull- See Also:
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print
Prints a string. If the argument isnullthen the string"null"is printed. Otherwise, the string's characters are converted into bytes according to the default charset, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
s- TheStringto be printed- See Also:
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print
Prints an object. The string produced by theString.valueOf(Object)method is translated into bytes according to the default charset, and these bytes are written in exactly the manner of thewrite(int)method.- Parameters:
obj- TheObjectto be printed- See Also:
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println
public void println()Terminates the current line by writing the line separator string. The line separator isSystem.lineSeparator()and is not necessarily a single newline character ('\n'). -
println
public 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- thebooleanvalue to be printed
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println
public void println(char x) Prints a character and then terminates the line. This method behaves as though it invokesprint(char)and thenprintln().- Parameters:
x- thecharvalue to be printed
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println
public void println(int x) Prints an integer and then terminates the line. This method behaves as though it invokesprint(int)and thenprintln().- Parameters:
x- theintvalue to be printed
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println
public 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- thelongvalue to be printed
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println
public 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- thefloatvalue to be printed
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println
public 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- thedoublevalue to be printed
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println
public 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 ofcharvalues to be printed
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println
Prints a String and then terminates the line. This method behaves as though it invokesprint(String)and thenprintln().- Parameters:
x- theStringvalue to be printed
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println
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- TheObjectto be printed.
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printf
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 anullargument 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 theformatisnull- Since:
- 1.5
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printf
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. Iflisnullthen 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 anullargument 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 theformatisnull- Since:
- 1.5
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format
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 anullargument 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 theformatisnull- Since:
- 1.5
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format
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. Iflisnullthen 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 anullargument 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 theformatisnull- Since:
- 1.5
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append
Appends the specified character sequence to this writer.An invocation of this method of the form
out.append(csq)whencsqis notnull, 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 interfaceAppendable- Overrides:
appendin classWriter- Parameters:
csq- The character sequence to append. Ifcsqisnull, then the four characters"null"are appended to this writer.- Returns:
- This writer
- Since:
- 1.5
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append
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 interfaceAppendable- Overrides:
appendin classWriter- Parameters:
csq- The character sequence from which a subsequence will be appended. Ifcsqisnull, then characters will be appended as ifcsqcontained the four characters"null".start- The index of the first character in the subsequenceend- The index of the character following the last character in the subsequence- Returns:
- This writer
- Throws:
IndexOutOfBoundsException- Ifstartorendare negative,startis greater thanend, orendis greater thancsq.length()- Since:
- 1.5
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append
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 interfaceAppendable- Overrides:
appendin classWriter- Parameters:
c- The 16-bit character to append- Returns:
- This writer
- Since:
- 1.5
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