Closeable
, Flushable
, Appendable
, AutoCloseable
public class PrintWriter extends Writer
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.
Modifier and Type | Field | Description |
---|---|---|
protected Writer |
out |
The underlying character-output stream of this PrintWriter . |
Constructor | Description |
---|---|
PrintWriter |
Creates a new PrintWriter, without automatic line flushing, with the specified file. |
PrintWriter |
Creates a new PrintWriter, without automatic line flushing, with the specified file and charset. |
PrintWriter |
Creates a new PrintWriter, without automatic line flushing, with the specified file and charset. |
PrintWriter |
Creates a new PrintWriter, without automatic line flushing, from an existing OutputStream. |
PrintWriter |
Creates a new PrintWriter from an existing OutputStream. |
PrintWriter |
Creates a new PrintWriter from an existing OutputStream. |
PrintWriter |
Creates a new PrintWriter, without automatic line flushing. |
PrintWriter |
Creates a new PrintWriter. |
PrintWriter |
Creates a new PrintWriter, without automatic line flushing, with the specified file name. |
PrintWriter |
Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset. |
PrintWriter |
Creates a new PrintWriter, without automatic line flushing, with the specified file name and charset. |
Modifier and Type | Method | Description |
---|---|---|
PrintWriter |
append |
Appends the specified character to this writer. |
PrintWriter |
append |
Appends the specified character sequence to this writer. |
PrintWriter |
append |
Appends a subsequence of the specified character sequence to this writer. |
boolean |
checkError() |
Flushes the stream if it's not closed and checks its error state. |
protected void |
clearError() |
Clears the error state of this stream. |
void |
close() |
Closes the stream and releases any system resources associated with it. |
void |
flush() |
Flushes the stream. |
PrintWriter |
format |
Writes a formatted string to this writer using the specified format string and arguments. |
PrintWriter |
format |
Writes a formatted string to this writer using the specified format string and arguments. |
void |
print |
Prints a boolean value. |
void |
print |
Prints a character. |
void |
print |
Prints an array of characters. |
void |
print |
Prints a double-precision floating-point number. |
void |
print |
Prints a floating-point number. |
void |
print |
Prints an integer. |
void |
print |
Prints a long integer. |
void |
print |
Prints an object. |
void |
print |
Prints a string. |
PrintWriter |
printf |
A convenience method to write a formatted string to this writer using the specified format string and arguments. |
PrintWriter |
printf |
A convenience method to write a formatted string to this writer using the specified format string and arguments. |
void |
println() |
Terminates the current line by writing the line separator string. |
void |
println |
Prints a boolean value and then terminates the line. |
void |
println |
Prints a character and then terminates the line. |
void |
println |
Prints an array of characters and then terminates the line. |
void |
println |
Prints a double-precision floating-point number and then terminates the line. |
void |
println |
Prints a floating-point number and then terminates the line. |
void |
println |
Prints an integer and then terminates the line. |
void |
println |
Prints a long integer and then terminates the line. |
void |
println |
Prints an Object and then terminates the line. |
void |
println |
Prints a String and then terminates the line. |
protected void |
setError() |
Sets the error state of the stream to true . |
void |
write |
Writes an array of characters. |
void |
write |
Writes A Portion of an array of characters. |
void |
write |
Writes a single character. |
void |
write |
Writes a string. |
void |
write |
Writes a portion of a string. |
nullWriter
protected Writer out
PrintWriter
.public PrintWriter(Writer out)
out
- A character-output streampublic PrintWriter(Writer out, boolean autoFlush)
out
- A character-output streamautoFlush
- A boolean; if true, the println
, printf
, or format
methods will flush the output bufferpublic PrintWriter(OutputStream out)
out
is a PrintStream
, the charset used by the print stream.out
- An output streampublic PrintWriter(OutputStream out, boolean autoFlush)
out
is a PrintStream
, the charset used by the print stream.out
- An output streamautoFlush
- A boolean; if true, the println
, printf
, or format
methods will flush the output bufferpublic PrintWriter(OutputStream out, boolean autoFlush, Charset charset)
out
- An output streamautoFlush
- A boolean; if true, the println
, printf
, or format
methods will flush the output buffercharset
- A charset
public PrintWriter(String fileName) throws FileNotFoundException
OutputStreamWriter
, which will encode characters using the default charset for this instance of the Java virtual machine.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.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 fileSecurityException
- If a security manager is present and checkWrite(fileName)
denies write access to the filepublic PrintWriter(String fileName, String csn) throws FileNotFoundException, UnsupportedEncodingException
OutputStreamWriter
, which will encode characters using the provided charset.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
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 fileSecurityException
- If a security manager is present and checkWrite(fileName)
denies write access to the fileUnsupportedEncodingException
- If the named charset is not supportedpublic PrintWriter(String fileName, Charset charset) throws IOException
OutputStreamWriter
, which will encode characters using the provided charset.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
IOException
- if an I/O error occurs while opening or creating the fileSecurityException
- If a security manager is present and checkWrite(fileName)
denies write access to the filepublic PrintWriter(File file) throws FileNotFoundException
OutputStreamWriter
, which will encode characters using the default charset for this instance of the Java virtual machine.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.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 fileSecurityException
- If a security manager is present and checkWrite(file.getPath())
denies write access to the filepublic PrintWriter(File file, String csn) throws FileNotFoundException, UnsupportedEncodingException
OutputStreamWriter
, which will encode characters using the provided charset.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
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 fileSecurityException
- If a security manager is present and checkWrite(file.getPath())
denies write access to the fileUnsupportedEncodingException
- If the named charset is not supportedpublic PrintWriter(File file, Charset charset) throws IOException
OutputStreamWriter
, which will encode characters using the provided charset.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
IOException
- if an I/O error occurs while opening or creating the fileSecurityException
- If a security manager is present and checkWrite(file.getPath())
denies write access to the filepublic void flush()
public void close()
public boolean checkError()
true
if and only if this stream has encountered an IOException
, or the setError
method has been invokedprotected void setError()
true
. This method will cause subsequent invocations of checkError()
to return true
until clearError()
is invoked.
protected void clearError()
This method will cause subsequent invocations of checkError()
to return false
until another write operation fails and invokes setError()
.
public void write(int c)
public void write(char[] buf, int off, int len)
write
in class Writer
buf
- Array of charactersoff
- Offset from which to start writing characterslen
- Number of characters to writeIndexOutOfBoundsException
- If the values of the off
and len
parameters cause the corresponding method of the underlying Writer
to throw an IndexOutOfBoundsException
public void write(char[] buf)
public void write(String s, int off, int len)
write
in class Writer
s
- A Stringoff
- Offset from which to start writing characterslen
- Number of characters to writeIndexOutOfBoundsException
- If the values of the off
and len
parameters cause the corresponding method of the underlying Writer
to throw an IndexOutOfBoundsException
public void write(String s)
public void print(boolean b)
String.valueOf(boolean)
is translated into bytes according to the default charset, and these bytes are written in exactly the manner of the write(int)
method.b
- The boolean
to be printedpublic void print(char c)
write(int)
method.c
- The char
to be printedpublic void print(int i)
String.valueOf(int)
is translated into bytes according to the default charset, and these bytes are written in exactly the manner of the write(int)
method.i
- The int
to be printedpublic void print(long l)
String.valueOf(long)
is translated into bytes according to the default charset, and these bytes are written in exactly the manner of the write(int)
method.l
- The long
to be printedpublic void print(float f)
String.valueOf(float)
is translated into bytes according to the default charset, and these bytes are written in exactly the manner of the write(int)
method.f
- The float
to be printedpublic void print(double d)
String.valueOf(double)
is translated into bytes according to the default charset, and these bytes are written in exactly the manner of the write(int)
method.d
- The double
to be printedpublic void print(char[] s)
write(int)
method.s
- The array of chars to be printedNullPointerException
- If s
is null
public void print(String s)
null
then 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 the write(int)
method.s
- The String
to be printedpublic void print(Object obj)
String.valueOf(Object)
method is translated into bytes according to the default charset, and these bytes are written in exactly the manner of the write(int)
method.obj
- The Object
to be printedpublic void println()
System.lineSeparator()
and is not necessarily a single newline character ('\n'
).public void println(boolean x)
print(boolean)
and then println()
.x
- the boolean
value to be printedpublic void println(char x)
print(char)
and then println()
.x
- the char
value to be printedpublic void println(int x)
print(int)
and then println()
.x
- the int
value to be printedpublic void println(long x)
print(long)
and then println()
.x
- the long
value to be printedpublic void println(float x)
print(float)
and then println()
.x
- the float
value to be printedpublic void println(double x)
print(double)
and then println()
.x
- the double
value to be printedpublic void println(char[] x)
print(char[])
and then println()
.x
- the array of char
values to be printedpublic void println(String x)
print(String)
and then println()
.x
- the String
value to be printedpublic void println(Object x)
print(String)
and then println()
.x
- The Object
to be printed.public PrintWriter printf(String format, Object... args)
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)
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 null
argument depends on the conversion.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 format
is null
public PrintWriter printf(Locale l, String format, Object... args)
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)
l
- The locale to apply during formatting. If l
is null
then 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 null
argument depends on the conversion.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 format
is null
public PrintWriter format(String format, Object... args)
The locale always used is the one returned by Locale.getDefault()
, regardless of any previous invocations of other formatting methods on this object.
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 null
argument depends on the conversion.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 format
is null
public PrintWriter format(Locale l, String format, Object... args)
l
- The locale to apply during formatting. If l
is null
then 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 null
argument depends on the conversion.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 format
is null
public PrintWriter append(CharSequence csq)
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.
append
in interface Appendable
append
in class Writer
csq
- The character sequence to append. If csq
is null
, then the four characters "null"
are appended to this writer.public PrintWriter append(CharSequence csq, int start, int end)
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())
append
in interface Appendable
append
in class Writer
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"
.start
- The index of the first character in the subsequenceend
- The index of the character following the last character in the subsequenceIndexOutOfBoundsException
- If start
or end
are negative, start
is greater than end
, or end
is greater than csq.length()
public PrintWriter append(char c)
An invocation of this method of the form out.append(c)
behaves in exactly the same way as the invocation
out.write(c)
append
in interface Appendable
append
in class Writer
c
- The 16-bit character to append
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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
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