Class PrintStream
- All Implemented Interfaces:
Closeable
,Flushable
,Appendable
,AutoCloseable
- Direct Known Subclasses:
LogStream
PrintStream
adds functionality to another output stream,
namely the ability to print representations of various data values
conveniently. Two other features are provided as well. Unlike other output
streams, a PrintStream
never throws an
IOException
; instead, exceptional situations merely set an
internal flag that can be tested via the checkError
method.
Optionally, a PrintStream
can be created so as to flush
automatically; this means that the flush
method of the underlying
output stream is automatically invoked after a byte array is written, one
of the println
methods is invoked, or a newline character or byte
('\n'
) is written.
All characters printed by a PrintStream
are converted into
bytes using the given encoding or charset, or the default charset if not
specified.
The PrintWriter
class should be used in situations that require
writing characters rather than bytes.
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:
- 1.0
- See Also:
-
Field Summary
Fields declared in class java.io.FilterOutputStream
out
-
Constructor Summary
ConstructorDescriptionPrintStream
(File file) Creates a new print stream, without automatic line flushing, with the specified file.PrintStream
(File file, String csn) Creates a new print stream, without automatic line flushing, with the specified file and charset.PrintStream
(File file, Charset charset) Creates a new print stream, without automatic line flushing, with the specified file and charset.PrintStream
(OutputStream out) Creates a new print stream, without automatic line flushing, with the specified OutputStream.PrintStream
(OutputStream out, boolean autoFlush) Creates a new print stream, with the specified OutputStream and line flushing.PrintStream
(OutputStream out, boolean autoFlush, String encoding) Creates a new print stream, with the specified OutputStream, line flushing, and character encoding.PrintStream
(OutputStream out, boolean autoFlush, Charset charset) Creates a new print stream, with the specified OutputStream, line flushing and charset.PrintStream
(String fileName) Creates a new print stream, without automatic line flushing, with the specified file name.PrintStream
(String fileName, String csn) Creates a new print stream, without automatic line flushing, with the specified file name and charset.PrintStream
(String fileName, Charset charset) Creates a new print stream, without automatic line flushing, with the specified file name and charset. -
Method Summary
Modifier and TypeMethodDescriptionappend
(char c) Appends the specified character to this output stream.append
(CharSequence csq) Appends the specified character sequence to this output stream.append
(CharSequence csq, int start, int end) Appends a subsequence of the specified character sequence to this output stream.charset()
Returns the charset used in thisPrintStream
instance.boolean
Flushes the stream if it's not closed and checks its error state.protected void
Clears the error state of this stream.void
close()
Closes the stream.void
flush()
Flushes the stream.Writes a formatted string to this output stream using the specified format string and arguments.Writes a formatted string to this output stream using the specified format string and arguments.void
print
(boolean b) Prints a boolean value.void
print
(char c) Prints a character.void
print
(char[] s) Prints an array of characters.void
print
(double d) Prints a double-precision floating-point number.void
print
(float f) Prints a floating-point number.void
print
(int i) Prints an integer.void
print
(long l) Prints a long integer.void
Prints an object.void
Prints a string.A convenience method to write a formatted string to this output stream using the specified format string and arguments.A convenience method to write a formatted string to this output stream using the specified format string and arguments.void
println()
Terminates the current line by writing the line separator string.void
println
(boolean x) Prints a boolean and then terminates the line.void
println
(char x) Prints a character and then terminates the line.void
println
(char[] x) Prints an array of characters and then terminates the line.void
println
(double x) Prints a double and then terminates the line.void
println
(float x) Prints a float and then terminates the line.void
println
(int x) Prints an integer and then terminates the line.void
println
(long x) Prints a long and then terminates the line.void
Prints an Object and then terminates the line.void
Prints a String and then terminates the line.protected void
setError()
Sets the error state of the stream totrue
.void
write
(byte[] buf) Writes all bytes from the specified byte array to this stream.void
write
(byte[] buf, int off, int len) Writeslen
bytes from the specified byte array starting at offsetoff
to this stream.void
write
(int b) Writes the specified byte to this stream.void
writeBytes
(byte[] buf) Writes all bytes from the specified byte array to this stream.Methods declared in class java.io.OutputStream
nullOutputStream
-
Constructor Details
-
PrintStream
Creates a new print stream, without automatic line flushing, with the specified OutputStream. Characters written to the stream are converted to bytes using the default charset, or whereout
is aPrintStream
, the charset used by the print stream.- Parameters:
out
- The output stream to which values and objects will be printed- See Also:
-
PrintStream
Creates a new print stream, with the specified OutputStream and line flushing. Characters written to the stream are converted to bytes using the default charset, or whereout
is aPrintStream
, the charset used by the print stream.- Parameters:
out
- The output stream to which values and objects will be printedautoFlush
- Whether the output buffer will be flushed whenever a byte array is written, one of theprintln
methods is invoked, or a newline character or byte ('\n'
) is written- See Also:
-
PrintStream
public PrintStream(OutputStream out, boolean autoFlush, String encoding) throws UnsupportedEncodingException Creates a new print stream, with the specified OutputStream, line flushing, and character encoding.- Parameters:
out
- The output stream to which values and objects will be printedautoFlush
- Whether the output buffer will be flushed whenever a byte array is written, one of theprintln
methods is invoked, or a newline character or byte ('\n'
) is writtenencoding
- The name of a supported character encoding- Throws:
UnsupportedEncodingException
- If the named encoding is not supported- Since:
- 1.4
-
PrintStream
Creates a new print stream, with the specified OutputStream, line flushing and charset. This convenience constructor creates the necessary intermediateOutputStreamWriter
, which will encode characters using the provided charset.- Parameters:
out
- The output stream to which values and objects will be printedautoFlush
- Whether the output buffer will be flushed whenever a byte array is written, one of theprintln
methods is invoked, or a newline character or byte ('\n'
) is writtencharset
- A charset- Since:
- 10
-
PrintStream
Creates a new print stream, 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 print stream. 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 fileSecurityException
- If a security manager is present andcheckWrite(fileName)
denies write access to the file- Since:
- 1.5
- See Also:
-
PrintStream
public PrintStream(String fileName, String csn) throws FileNotFoundException, UnsupportedEncodingException Creates a new print stream, 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 print stream. 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 fileSecurityException
- If a security manager is present andcheckWrite(fileName)
denies write access to the fileUnsupportedEncodingException
- If the named charset is not supported- Since:
- 1.5
-
PrintStream
Creates a new print stream, 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 print stream. 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 fileSecurityException
- If a security manager is present andcheckWrite(fileName)
denies write access to the file- Since:
- 10
-
PrintStream
Creates a new print stream, 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 print stream. 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 fileSecurityException
- If a security manager is present andcheckWrite(file.getPath())
denies write access to the file- Since:
- 1.5
- See Also:
-
PrintStream
public PrintStream(File file, String csn) throws FileNotFoundException, UnsupportedEncodingException Creates a new print stream, 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 print stream. 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 fileSecurityException
- If a security manager is present andcheckWrite(file.getPath())
denies write access to the fileUnsupportedEncodingException
- If the named charset is not supported- Since:
- 1.5
-
PrintStream
Creates a new print stream, 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 print stream. 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 fileSecurityException
- If a security manager is present andcheckWrite(file.getPath())
denies write access to the file- Since:
- 10
-
-
Method Details
-
flush
public void flush()Flushes the stream. This is done by writing any buffered output bytes to the underlying output stream and then flushing that stream.- Specified by:
flush
in interfaceFlushable
- Overrides:
flush
in classFilterOutputStream
- See Also:
-
close
public void close()Closes the stream. This is done by flushing the stream and then closing the underlying output stream.- Specified by:
close
in interfaceAutoCloseable
- Specified by:
close
in interfaceCloseable
- Overrides:
close
in classFilterOutputStream
- See Also:
-
checkError
public boolean checkError()Flushes the stream if it's not closed and checks its error state.- Returns:
true
if and only if this stream has encountered anIOException
, or thesetError
method has been invoked
-
setError
protected void setError()Sets the error state of the stream totrue
.This method will cause subsequent invocations of
checkError()
to returntrue
untilclearError()
is invoked.- Since:
- 1.1
-
clearError
protected void clearError()Clears the error state of this stream.This method will cause subsequent invocations of
checkError()
to returnfalse
until another write operation fails and invokessetError()
.- Since:
- 1.6
-
write
public void write(int b) Writes the specified byte to this stream. If the byte is a newline and automatic flushing is enabled then theflush
method will be invoked on the underlying output stream.Note that the byte is written as given; to write a character that will be translated according to the default charset, use the
print(char)
orprintln(char)
methods.- Overrides:
write
in classFilterOutputStream
- Parameters:
b
- The byte to be written- See Also:
-
write
public void write(byte[] buf, int off, int len) Writeslen
bytes from the specified byte array starting at offsetoff
to this stream. If automatic flushing is enabled then theflush
method will be invoked on the underlying output stream.Note that the bytes will be written as given; to write characters that will be translated according to the default charset, use the
print(char)
orprintln(char)
methods.- Overrides:
write
in classFilterOutputStream
- Parameters:
buf
- A byte arrayoff
- Offset from which to start taking byteslen
- Number of bytes to write- Throws:
IndexOutOfBoundsException
- Ifoff
is negative,len
is negative, orlen
is greater thanb.length - off
- See Also:
-
write
Writes all bytes from the specified byte array to this stream. If automatic flushing is enabled then theflush
method will be invoked on the underlying output stream.Note that the bytes will be written as given; to write characters that will be translated according to the default charset, use the
print(char[])
orprintln(char[])
methods.- Overrides:
write
in classFilterOutputStream
- API Note:
- Although declared to throw
IOException
, this method never actually does so. Instead, like other methods that this class overrides, it sets an internal flag which may be tested via thecheckError()
method. To write an array of bytes without having to write acatch
block for theIOException
, use eitherwriteBytes(buf)
orwrite(buf, 0, buf.length)
. - Implementation Requirements:
- This method is equivalent to
this.write(buf, 0, buf.length)
. - Parameters:
buf
- A byte array- Throws:
IOException
- If an I/O error occurs.- See Also:
-
writeBytes
public void writeBytes(byte[] buf) Writes all bytes from the specified byte array to this stream. If automatic flushing is enabled then theflush
method will be invoked.Note that the bytes will be written as given; to write characters that will be translated according to the default charset, use the
print(char[])
orprintln(char[])
methods.- Implementation Requirements:
- This method is equivalent to
this.write(buf, 0, buf.length)
. - Parameters:
buf
- A byte array- Since:
- 14
-
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
- Theboolean
to be printed- See Also:
-
print
public void print(char c) Prints a character. The character is translated into one or more bytes according to the character encoding given to the constructor, or the default charset if none specified. These bytes are written in exactly the manner of thewrite(int)
method.- Parameters:
c
- Thechar
to be printed- See Also:
-
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
- Theint
to be printed- See Also:
-
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
- Thelong
to be printed- See Also:
-
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
- Thefloat
to be printed- See Also:
-
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
- Thedouble
to be printed- See Also:
-
print
public void print(char[] s) Prints an array of characters. The characters are converted into bytes according to the character encoding given to the constructor, or the default charset if none specified. These bytes are written in exactly the manner of thewrite(int)
method.- Parameters:
s
- The array of chars to be printed- Throws:
NullPointerException
- Ifs
isnull
- See Also:
-
print
Prints a string. If the argument isnull
then the string"null"
is printed. Otherwise, the string's characters are converted into bytes according to the character encoding given to the constructor, or the default charset if none specified. These bytes are written in exactly the manner of thewrite(int)
method.- Parameters:
s
- TheString
to be printed- See Also:
-
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
- TheObject
to be printed- See Also:
-
println
public 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'
). -
println
public void println(boolean x) Prints a boolean and then terminates the line. This method behaves as though it invokesprint(boolean)
and thenprintln()
.- Parameters:
x
- Theboolean
to be printed
-
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
- Thechar
to be printed.
-
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
- Theint
to be printed.
-
println
public void println(long x) Prints a long and then terminates the line. This method behaves as though it invokesprint(long)
and thenprintln()
.- Parameters:
x
- a Thelong
to be printed.
-
println
public void println(float x) Prints a float and then terminates the line. This method behaves as though it invokesprint(float)
and thenprintln()
.- Parameters:
x
- Thefloat
to be printed.
-
println
public void println(double x) Prints a double and then terminates the line. This method behaves as though it invokesprint(double)
and thenprintln()
.- Parameters:
x
- Thedouble
to be printed.
-
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
- an array of chars to print.
-
println
Prints a String and then terminates the line. This method behaves as though it invokesprint(String)
and thenprintln()
.- Parameters:
x
- TheString
to be printed.
-
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
- TheObject
to be printed.
-
printf
A convenience method to write a formatted string to this output stream using the specified format string and arguments.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 syntaxargs
- 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 anull
argument depends on the conversion.- Returns:
- This output stream
- 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 theformat
isnull
- Since:
- 1.5
-
printf
A convenience method to write a formatted string to this output stream using the specified format string and arguments.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. Ifl
isnull
then no localization is applied.format
- A format string as described in Format string syntaxargs
- 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 anull
argument depends on the conversion.- Returns:
- This output stream
- 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 theformat
isnull
- Since:
- 1.5
-
format
Writes a formatted string to this output stream using the specified format string and arguments.The locale always used is the one returned by
Locale.getDefault(Locale.Category)
withFORMAT
category specified, regardless of any previous invocations of other formatting methods on this object.- Parameters:
format
- A format string as described in Format string syntaxargs
- 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 anull
argument depends on the conversion.- Returns:
- This output stream
- 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 theformat
isnull
- Since:
- 1.5
-
format
Writes a formatted string to this output stream using the specified format string and arguments.- Parameters:
l
- The locale to apply during formatting. Ifl
isnull
then no localization is applied.format
- A format string as described in Format string syntaxargs
- 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 anull
argument depends on the conversion.- Returns:
- This output stream
- 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 theformat
isnull
- Since:
- 1.5
-
append
Appends the specified character sequence to this output stream.An invocation of this method of the form
out.append(csq)
whencsq
is notnull
, behaves in exactly the same way as the invocationout.print(csq.toString())
Depending on the specification of
toString
for the character sequencecsq
, the entire sequence may not be appended. For instance, invoking thetoString
method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.- Specified by:
append
in interfaceAppendable
- Parameters:
csq
- The character sequence to append. Ifcsq
isnull
, then the four characters"null"
are appended to this output stream.- Returns:
- This output stream
- Since:
- 1.5
-
append
Appends a subsequence of the specified character sequence to this output stream.An invocation of this method of the form
out.append(csq, start, end)
whencsq
is notnull
, behaves in exactly the same way as the invocationout.print(csq.subSequence(start, end).toString())
- Specified by:
append
in interfaceAppendable
- Parameters:
csq
- The character sequence from which a subsequence will be appended. Ifcsq
isnull
, then characters will be appended as ifcsq
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 subsequence- Returns:
- This output stream
- Throws:
IndexOutOfBoundsException
- Ifstart
orend
are negative,start
is greater thanend
, orend
is greater thancsq.length()
- Since:
- 1.5
-
append
Appends the specified character to this output stream.An invocation of this method of the form
out.append(c)
behaves in exactly the same way as the invocationout.print(c)
- Specified by:
append
in interfaceAppendable
- Parameters:
c
- The 16-bit character to append- Returns:
- This output stream
- Since:
- 1.5
-
charset
Returns the charset used in thisPrintStream
instance.- Returns:
- the charset used in this
PrintStream
instance - Since:
- 18
-