java.io.PrintWriter
PrintWriter is a class which takes either an OutputStream or Writer and
provides convenience methods for printing common data types in a human
readable format on the stream. No IOExceptions are thrown by this class.
Instead, callers should call checkError() to see if a problem has been
encountered in this Writer.
Summary
Fields
protected |
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Writer |
out |
The writer to output data to. |
protected |
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Object |
lock |
The object used to synchronize access to the writer. |
Public Constructors
Public Methods
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PrintWriter |
append(char c) |
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PrintWriter |
append(CharSequence csq) |
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PrintWriter |
append(CharSequence csq, int start, int end) |
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boolean |
checkError() |
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void |
close() |
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void |
flush() |
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PrintWriter |
format(String format, Object[] args) |
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PrintWriter |
format(Locale l, String format, Object[] args) |
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void |
print(float fnum) |
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void |
print(char ch) |
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void |
print(Object obj) |
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void |
print(String str) |
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void |
print(int inum) |
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void |
print(double dnum) |
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void |
print(long lnum) |
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void |
print(char[] charArray) |
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void |
print(boolean bool) |
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PrintWriter |
printf(Locale l, String format, Object[] args) |
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PrintWriter |
printf(String format, Object[] args) |
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void |
println(double dnum) |
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void |
println(String str) |
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void |
println(boolean bool) |
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void |
println(long lnum) |
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void |
println(char ch) |
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void |
println(float fnum) |
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void |
println(char[] charArray) |
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void |
println(Object obj) |
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void |
println() |
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void |
println(int inum) |
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void |
write(char[] buf) |
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void |
write(String str) |
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void |
write(String str, int offset, int count) |
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void |
write(int oneChar) |
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void |
write(char[] buf, int offset, int count) |
Protected Methods
Methods inherited
from class
java.io.Writer
clone,
equals,
finalize,
getClass,
hashCode,
notify,
notifyAll,
toString,
wait,
wait,
wait
Details
Fields
protected
Writer
out
The writer to output data to.
Public Constructors
Constructs a new PrintWriter on the OutputStream
out
. All
writes to the target can now take place through this PrintWriter. By
default, the PrintWriter is set to not autoflush when println() is
called.
Parameters
out
| the the OutputStream to provide convenience methods on.
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public
PrintWriter(OutputStream out, boolean autoflush)
Constructs a new PrintWriter on the OutputStream
out
. All
writes to the target can now take place through this PrintWriter. By
default, the PrintWriter is set to not autoflush when println() is
called.
Parameters
out
| the the OutputStream to provide convenience methods on. |
autoflush
| whether to flush when println() is called.
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public
PrintWriter(Writer wr)
Constructs a new PrintWriter on the Writer
wr
. All writes
to the target can now take place through this PrintWriter. By default,
the PrintWriter is set to not autoflush when println() is called.
Parameters
wr
| the Writer to provide convenience methods on.
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public
PrintWriter(Writer wr, boolean autoflush)
Constructs a new PrintWriter on the given writer. All writes to the
target can now take place through this PrintWriter. By default, the
PrintWriter is set to not autoflush when println() is called.
Parameters
wr
| the Writer to provide convenience methods on. |
autoflush
| whether to flush when println() is called.
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public
PrintWriter(File file)
Constructs a new PrintWriter on the File
file
. The
automatic flushing is set to
false
. An intermediate
OutputStreamWriter
will use the default for the current
JVM instance charset to encode characters.
Parameters
file
| This writer's buffered destination. |
Throws
FileNotFoundException
| If there is no such a file or some other error occurs due to
the given file opening.
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public
PrintWriter(File file, String csn)
Constructs a new PrintWriter on the File
file
. The
automatic flushing is set to
false
. An intermediate
OutputStreamWriter
will use a charset with the given name
csn
to encode characters.
Parameters
file
| This writer's buffered destination. |
csn
| A charset name. |
public
PrintWriter(String fileName)
Constructs a new PrintWriter on a file with the given file name
fileName
. The automatic flushing is set to
false
. An intermediate
OutputStreamWriter
will use the default for the current JVM instance charset to encode
characters.
Parameters
fileName
| The name of file which is this writer's buffered destination. |
Throws
FileNotFoundException
| If there is no such a file or some other error occurs due to
the given file opening.
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public
PrintWriter(String fileName, String csn)
Constructs a new PrintWriter on a file with the given file name
fileName
. The automatic flushing is set to
false
. An intermediate
OutputStreamWriter
will use a charset with the given name
csn
to encode
characters.
Parameters
fileName
| The name of file which is this writer's buffered destination. |
csn
| A charset name. |
Public Methods
Append a char
c
to the PrintWriter. The
PrintWriter.append(
c
) works the same way as
PrintWriter.write(
c
).
Parameters
c
| The character appended to the PrintWriter. |
Append a CharSequence
csq
to the PrintWriter. The
PrintWriter.append(
csq
) works the same way as
PrintWriter.write(
csq
.toString()). If
csq
is null, then "null" will be substituted for
csq
Parameters
csq
| The CharSequence appended to the PrintWriter. |
Append a subsequence of a CharSequence
csq
to the
PrintWriter. The first char and the last char of the subsequence is
specified by the parameter
start
and
end
.
The PrintWriter.append(
csq
) works the same way as
PrintWriter.write(
csq
.subSequence(
start
,
end
).toString).If
csq
is null, then "null" will be substituted for
csq
.
Parameters
csq
| The CharSequence appended to the PrintWriter. |
start
| The index of the first char in the CharSequence appended to
the PrintWriter. |
end
| The index of the char after the last one in the CharSequence
appended to the PrintWriter. |
Throws
IndexOutOfBoundsException
| If start is less than end, end is greater than the length of
the CharSequence, or start or end is negative.
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public
boolean
checkError()
Returns a boolean indicating whether or not this PrintWriter has
encountered an error. If so, the receiver should probably be closed since
further writes will not actually take place. A side effect of calling
checkError is that the target Writer is flushed.
Returns
- boolean has an error occurred in this PrintWriter.
public
void
close()
Close this PrintWriter. This implementation flushes and then closes the
target writer. If an error occurs, set an error in this PrintWriter to
true
.
public
void
flush()
Flush this PrintWriter to ensure all pending data is sent out to the
target Writer. This implementation flushes the target writer. If an error
occurs, set an error in this PrintWriter to true
.
Writes a string formatted by an intermediate
Formatter
to
this writer using the given format string and arguments. A call to this
method flushes the buffered output, if the automatic flushing is enabled.
The method uses the default for the current JVM instance locale, as if it
is specified by the Locale.getDefault()
call.
Parameters
format
| A format string. |
args
| The arguments list. If there are more arguments than those
specified by the format string, then the additional arguments
are ignored. |
Throws
IllegalFormatException
| If the format string is illegal or incompatible with the
arguments or the arguments are less than those required by
the format string or any other illegal situation. |
NullPointerException
| If the given format is null.
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Writes a string formatted by an intermediate
Formatter
to
this writer using the given format string and arguments. A call to this
method flushes the buffered output, if the automatic flushing is enabled.
Parameters
l
| The locale used in the method. If locale is null, then no
localization will be applied. |
format
| A format string. |
args
| The arguments list. If there are more arguments than those
specified by the format string, then the additional arguments
are ignored. |
Throws
IllegalFormatException
| If the format string is illegal or incompatible with the
arguments or the arguments are less than those required by
the format string or any other illegal situation. |
NullPointerException
| If the given format is null.
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public
void
print(float fnum)
Prints the String representation of the
float
parameter
fnum
to the target Writer.
Parameters
fnum
| the float to print on this Writer.
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public
void
print(char ch)
Prints the String representation of the character parameter
ch
to the target Writer.
Parameters
ch
| the character to print on this Writer.
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public
void
print(Object obj)
Prints the String representation of the Object parameter
obj
to the target Writer.
Parameters
obj
| the Object to print on this Writer.
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public
void
print(String str)
Prints the String representation of the
String
parameter
str
to the target Writer.
Parameters
str
| the String to print on this Writer.
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public
void
print(int inum)
Prints the String representation of the
int
parameter
inum
to the target Writer.
Parameters
inum
| the int to print on this Writer.
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public
void
print(double dnum)
Prints the String representation of the
double
parameter
dnum
to the target Writer.
Parameters
dnum
| the double to print on this Writer.
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public
void
print(long lnum)
Prints the String representation of the
long
parameter
lnum
to the target Writer.
Parameters
lnum
| the long to print on this Writer.
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public
void
print(char[] charArray)
Prints the String representation of the character array parameter
charArray
to the target Writer.
Parameters
charArray
| the character array to print on this Writer.
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public
void
print(boolean bool)
Prints the String representation of the
boolean
parameter
bool
to the target Writer.
Parameters
bool
| the boolean to print on this Writer.
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Prints a formatted string. The behavior of this method is the same as
this writer's
format(Locale l, String format, Object... args)
method.
Parameters
l
| The locale used in the method. If locale is null, then no
localization will be applied. |
format
| A format string. |
args
| The arguments list. If there are more arguments than those
specified by the format string, then the additional arguments
are ignored. |
Throws
IllegalFormatException
| If the format string is illegal or incompatible with the
arguments or the arguments are less than those required by
the format string or any other illegal situation. |
NullPointerException
| If the given format is null.
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Prints a formatted string. The behavior of this method is the same as
this writer's
format(String format, Object... args)
method.
The method uses the default for the current JVM instance locale, as if it
is specified by the Locale.getDefault()
call.
Parameters
format
| A format string. |
args
| The arguments list. If there are more arguments than those
specified by the format string, then the additional arguments
are ignored. |
Throws
IllegalFormatException
| If the format string is illegal or incompatible with the
arguments or the arguments are less than those required by
the format string or any other illegal situation. |
NullPointerException
| If the given format is null.
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public
void
println(double dnum)
Prints the String representation of the
double
parameter
dnum
to the target Writer followed by the System property
"line.separator"
.
Parameters
dnum
| the double to print on this Writer.
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public
void
println(String str)
Prints the String representation of the
String
parameter
str
to the target Writer followed by the System property
"line.separator"
.
Parameters
str
| the String to print on this Writer.
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public
void
println(boolean bool)
Prints the String representation of the
boolean
parameter
bool
to the target Writer followed by the System property
"line.separator"
.
Parameters
bool
| the boolean to print on this Writer.
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public
void
println(long lnum)
Prints the String representation of the
long
parameter
lnum
to the target Writer followed by the System property
"line.separator"
.
Parameters
lnum
| the long to print on this Writer.
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public
void
println(char ch)
Prints the String representation of the character parameter
ch
to the target Writer followed by the System property
"line.separator"
.
Parameters
ch
| the character to print on this Writer.
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public
void
println(float fnum)
Prints the String representation of the
float
parameter
fnum
to the target Writer followed by the System property
"line.separator"
.
Parameters
fnum
| the float to print on this Writer.
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public
void
println(char[] charArray)
Prints the String representation of the character array parameter
charArray
to the target Writer followed by the System
property
"line.separator"
.
Parameters
charArray
| the character array to print on this Writer.
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public
void
println(Object obj)
Prints the String representation of the
Object
parameter
obj
to the target Writer followed by the System property
"line.separator"
.
Parameters
obj
| the Object to print on this Writer.
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public
void
println()
Prints the String representation of the System property
"line.separator"
to the target Writer.
public
void
println(int inum)
Prints the String representation of the
int
parameter
inum
to the target Writer followed by the System property
"line.separator"
.
Parameters
inum
| the int to print on this Writer.
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public
void
write(char[] buf)
Writes the entire character buffer buf to this Writer.
Parameters
buf
| the non-null array containing characters to write.
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public
void
write(String str)
Writes the characters from the String
str
to this Writer.
Parameters
str
| the non-null String containing the characters to write.
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public
void
write(String str, int offset, int count)
Writes
count
characters from the String
str
starting at
offset
to this Writer.
Parameters
str
| the non-null String containing the characters to write. |
offset
| where in str to get chars from. |
count
| how many characters to write. |
public
void
write(int oneChar)
Writes the specified character to this Writer. This implementation writes
the low order two bytes to the target writer.
Parameters
oneChar
| The character to write
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public
void
write(char[] buf, int offset, int count)
Writes
count
characters starting at
offset
in
buf
to this Writer.
Parameters
buf
| the non-null array containing characters to write. |
offset
| offset in buf to retrieve characters |
count
| maximum number of characters to write |
Protected Methods
protected
void
setError()
Set the flag indicating that this PrintWriter has encountered an IO
error.