public class PrintStream extends FilterOutputStream implements Appendable, Closeable
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 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 platform's default character encoding. The
class should be used in situations that require writing
characters rather than bytes.PrintWriter
out
Constructor and Description |
---|
PrintStream(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(OutputStream out)
Creates a new print stream.
|
PrintStream(OutputStream out,
boolean autoFlush)
Creates a new print stream.
|
PrintStream(OutputStream out,
boolean autoFlush,
String encoding)
Creates a new print stream.
|
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.
|
Modifier and Type | Method and Description |
---|---|
PrintStream |
append(char c)
Appends the specified character to this output stream.
|
PrintStream |
append(CharSequence csq)
Appends the specified character sequence to this output stream.
|
PrintStream |
append(CharSequence csq,
int start,
int end)
Appends a subsequence of the specified character sequence to this output
stream.
|
boolean |
checkError()
Flushes the stream and checks its error state.
|
protected void |
clearError()
Clears the internal error state of this stream.
|
void |
close()
Closes the stream.
|
void |
flush()
Flushes the stream.
|
PrintStream |
format(Locale l,
String format,
Object... args)
Writes a formatted string to this output stream using the specified
format string and arguments.
|
PrintStream |
format(String format,
Object... args)
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 |
print(Object obj)
Prints an object.
|
void |
print(String s)
Prints a string.
|
PrintStream |
printf(Locale l,
String format,
Object... args)
A convenience method to write a formatted string to this output stream
using the specified format string and arguments.
|
PrintStream |
printf(String format,
Object... args)
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 terminate the line.
|
void |
println(char x)
Prints a character and then terminate the line.
|
void |
println(char[] x)
Prints an array of characters and then terminate the line.
|
void |
println(double x)
Prints a double and then terminate the line.
|
void |
println(float x)
Prints a float and then terminate the line.
|
void |
println(int x)
Prints an integer and then terminate the line.
|
void |
println(long x)
Prints a long and then terminate the line.
|
void |
println(Object x)
Prints an Object and then terminate the line.
|
void |
println(String x)
Prints a String and then terminate the line.
|
protected void |
setError()
Sets the error state of the stream to
true . |
void |
write(byte[] buf,
int off,
int len)
Writes
len bytes from the specified byte array starting at
offset off to this stream. |
void |
write(int b)
Writes the specified byte to this stream.
|
write
public PrintStream(OutputStream out)
out
- The output stream to which values and objects will be
printedPrintWriter.PrintWriter(java.io.OutputStream)
public PrintStream(OutputStream out, boolean autoFlush)
out
- The output stream to which values and objects will be
printedautoFlush
- A boolean; if true, the output buffer will be flushed
whenever a byte array is written, one of the
println
methods is invoked, or a newline
character or byte ('\n'
) is writtenPrintWriter.PrintWriter(java.io.OutputStream, boolean)
public PrintStream(OutputStream out, boolean autoFlush, String encoding) throws UnsupportedEncodingException
out
- The output stream to which values and objects will be
printedautoFlush
- A boolean; if true, the output buffer will be flushed
whenever a byte array is written, one of the
println
methods is invoked, or a newline
character or byte ('\n'
) is writtenencoding
- The name of a supported
character encodingUnsupportedEncodingException
- If the named encoding is not supportedpublic PrintStream(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 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.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(fileName)
denies write
access to the filepublic PrintStream(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 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 charsetFileNotFoundException
- 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(fileName)
denies write
access to the fileUnsupportedEncodingException
- If the named charset is not supportedpublic PrintStream(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 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.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 PrintStream(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 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 charsetFileNotFoundException
- 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 presentand checkWrite(file.getPath())
denies write access to the fileUnsupportedEncodingException
- If the named charset is not supportedpublic void flush()
flush
in interface Flushable
flush
in class FilterOutputStream
OutputStream.flush()
public void close()
close
in interface Closeable
close
in interface AutoCloseable
close
in class FilterOutputStream
OutputStream.close()
public boolean checkError()
true
when the underlying output stream throws an
IOException
other than InterruptedIOException
,
and when the setError
method is invoked. If an operation
on the underlying output stream throws an
InterruptedIOException
, then the PrintStream
converts the exception back into an interrupt by doing:
Thread.currentThread().interrupt();or the equivalent.
true
if and only if this stream has encountered an
IOException
other than
InterruptedIOException
, 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 b)
flush
method will be
invoked.
Note that the byte is written as given; to write a character that
will be translated according to the platform's default character
encoding, use the print(char)
or println(char)
methods.
write
in class FilterOutputStream
b
- The byte to be writtenprint(char)
,
println(char)
public void write(byte[] buf, int off, int len)
len
bytes from the specified byte array starting at
offset off
to this stream. If automatic flushing is
enabled then the flush
method will be invoked.
Note that the bytes will be written as given; to write characters
that will be translated according to the platform's default character
encoding, use the print(char)
or println(char)
methods.
write
in class FilterOutputStream
buf
- A byte arrayoff
- Offset from which to start taking byteslen
- Number of bytes to writeFilterOutputStream.write(int)
public void print(boolean b)
String.valueOf(boolean)
is translated into bytes
according to the platform's default character encoding, and these bytes
are written in exactly the manner of the
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 platform's default character encoding, and these bytes
are written in exactly the manner of the
write(int)
method.i
- The int
to be printedInteger.toString(int)
public void print(long l)
String.valueOf(long)
is translated into bytes
according to the platform's default character encoding, and these bytes
are written in exactly the manner of the
write(int)
method.l
- The long
to be printedLong.toString(long)
public void print(float f)
String.valueOf(float)
is translated into bytes
according to the platform's default character encoding, and these bytes
are written in exactly the manner of the
write(int)
method.f
- The float
to be printedFloat.toString(float)
public void print(double d)
String.valueOf(double)
is translated into
bytes according to the platform's default character encoding, and these
bytes are written in exactly the manner of the write(int)
method.d
- The double
to be printedDouble.toString(double)
public 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 platform's default character
encoding, 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 platform's default character encoding, and these bytes
are written in exactly the manner of the
write(int)
method.obj
- The Object
to be printedObject.toString()
public void println()
line.separator
, and is not necessarily a single newline
character ('\n'
).public void println(boolean x)
print(boolean)
and then
println()
.x
- The boolean
to be printedpublic void println(char x)
print(char)
and then
println()
.x
- The char
to be printed.public void println(int x)
print(int)
and then
println()
.x
- The int
to be printed.public void println(long x)
print(long)
and then
println()
.x
- a The long
to be printed.public void println(float x)
print(float)
and then
println()
.x
- The float
to be printed.public void println(double x)
print(double)
and then
println()
.x
- The double
to be printed.public void println(char[] x)
print(char[])
and
then println()
.x
- an array of chars to print.public void println(String x)
print(String)
and then
println()
.x
- The String
to be printed.public void println(Object x)
print(String)
and then
println()
.x
- The Object
to be printed.public PrintStream 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 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 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 nullpublic PrintStream 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 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 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 nullpublic PrintStream 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 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 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 nullpublic PrintStream 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 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 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 nullpublic PrintStream append(CharSequence csq)
An invocation of this method of the form out.append(csq) behaves in exactly the same way as the invocation
out.print(csq.toString())
Depending on the specification of toString for the character sequence csq, the entire sequence may not be appended. For instance, invoking then toString method of a character buffer will return a subsequence whose content depends upon the buffer's position and limit.
append
in interface Appendable
csq
- The character sequence to append. If csq is
null, then the four characters "null" are
appended to this output stream.public PrintStream 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.print(csq.subSequence(start, end).toString())
append
in interface Appendable
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 PrintStream append(char c)
An invocation of this method of the form out.append(c) behaves in exactly the same way as the invocation
out.print(c)
append
in interface Appendable
c
- The 16-bit character to append Submit a bug or feature
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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