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java.io
Class PrintWriter
java.lang.Object
java.io.Writer
java.io.PrintWriter
-
All Implemented Interfaces:
-
Closeable
,
Flushable
,
Appendable
-
public class PrintWriter
- extends Writer
Print formatted representations of objects to a text-output stream. This class implements all of the
print
methods found in
PrintStream
.
PrintStream.
It does not contain methods for writing raw bytes, for which a program should use unencoded byte streams.
Unlike the
PrintStream
PrintStream
class, if automatic flushing is enabled it will be done only when one of the
println
,
printf
, or
format
println()
methods is invoked, rather than whenever a newline character happens to be output.
These
The println()
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.
exceptions.
The client may inquire as to whether any errors have occurred by invoking
checkError()
.
checkError().
-
Since:
-
JDK1.1
Field Summary
|
protected
Writer
|
out
The underlying character-output stream of this PrintWriter. |
Constructor Summary
|
PrintWriter
(
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
(
OutputStream
out)
Create a new PrintWriter, without automatic line flushing, from an existing OutputStream. |
PrintWriter
(
OutputStream
out, boolean autoFlush)
Create a new PrintWriter from an existing OutputStream. |
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
(
Writer
out)
Create a new PrintWriter, without automatic line flushing. |
PrintWriter
(
Writer
out, boolean autoFlush)
Create a new PrintWriter. |
Method Summary
|
PrintWriter
|
append
(char c)
Appends the specified character to this writer. |
PrintWriter
|
append
(
CharSequence
csq)
Appends the specified character sequence to this writer. |
PrintWriter
|
append
(
CharSequence
Appends a subsequence of the specified character sequence to this writer.
|
boolean |
checkError
()
Flush the stream if it's not closed and check its error state. |
void |
close
()
Close the stream. |
void |
flush
()
Flush the stream. |
PrintWriter
|
format
(
Locale
l,
String
format,
Object
... args)
Writes a formatted string to this writer using the specified format string and arguments. |
PrintWriter
|
format
(
String
format,
Object
... args)
Writes a formatted string to this writer using the specified format string and arguments. |
void |
print
(boolean b)
Print a boolean value. |
void |
print
(char c)
Print a character. |
void |
print
(char[] s)
Print an array of characters. |
void |
print
(double d)
Print a double-precision floating-point number. |
void |
print
(float f)
Print a floating-point number. |
void |
print
(int i)
Print an integer. |
void |
print
(long l)
Print a long integer. |
void |
print
(
Object
obj)
Print an object. |
void |
print
(
String
s)
Print a string. |
PrintWriter
|
printf
(
Locale
l,
String
format,
Object
... args)
A convenience method to write a formatted string to this writer using the specified format string and arguments. |
PrintWriter
|
printf
(
String
format,
Object
... args)
A convenience method to write a formatted string to this writer using the specified format string and arguments. |
void |
println
()
Terminate the current line by writing the line separator string. |
void |
println
(boolean x)
Print a boolean value and then terminate the line. |
void |
println
(char x)
Print a character and then terminate the line. |
void |
println
(char[] x)
Print an array of characters and then terminate the line. |
void |
println
(double x)
Print a double-precision floating-point number and then terminate the line. |
void |
println
(float x)
Print a floating-point number and then terminate the line. |
void |
println
(int x)
Print an integer and then terminate the line. |
void |
println
(long x)
Print a long integer and then terminate the line. |
void |
println
(
Object
x)
Print an Object and then terminate the line. |
void |
println
(
String
x)
Print a String and then terminate the line. |
protected void |
setError
()
Indicate that an error has occurred. |
void |
write
(char[] buf)
Write an array of characters. |
void |
write
(char[] buf, int off, int len)
Write A Portion of an array of characters. |
void |
write
(int c)
Write a single character. |
void |
write
(
String
s)
Write a string. |
void |
write
(
String
s, int off, int len)
Write a portion of a string. |
Methods inherited from class java.lang.
Object
|
clone
,
equals
,
finalize
,
getClass
,
hashCode
,
notify
,
notifyAll
,
toString
,
wait
,
wait
,
wait
|
out
protected Writer out
-
The underlying character-output stream of this PrintWriter.
-
Since:
-
1.2
PrintWriter
public PrintWriter(Writer out)
-
Create a new PrintWriter, without automatic line flushing.
-
Parameters:
-
out - A character-output stream
PrintWriter
public PrintWriter(Writer out,
boolean autoFlush)
-
Create a new PrintWriter.
-
Parameters:
-
out - A character-output stream
-
autoFlush - A boolean; if true, the
println
,
printf
, or
format
println()
methods will flush the output buffer
PrintWriter
public PrintWriter(OutputStream out)
-
Create 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 character encoding.
-
Parameters:
-
out - An output stream
-
See Also:
-
OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)
PrintWriter
public PrintWriter(OutputStream out,
boolean autoFlush)
-
Create a new PrintWriter from an existing OutputStream. This convenience constructor creates the necessary intermediate OutputStreamWriter, which will convert characters into bytes using the default character encoding.
-
Parameters:
-
out - An output stream
-
autoFlush - A boolean; if true, the
println
,
printf
, or
format
println()
methods will flush the output buffer -
See Also:
-
OutputStreamWriter.OutputStreamWriter(java.io.OutputStream)
PrintWriter
public PrintWriter(String fileName)
throws FileNotFoundException
-
Creates a new PrintWriter, without automatic line flushing, with the specified file name. This convenience constructor creates the necessary intermediate
OutputStreamWriter
, 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
-
SecurityException
- If a security manager is present and
checkWrite(fileName)
denies write access to the file
-
Since:
-
1.5
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 intermediate
OutputStreamWriter
, 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 file
-
SecurityException
- If a security manager is present and
checkWrite(fileName)
denies write access to the file
-
UnsupportedEncodingException
- If the named charset is not supported
-
Since:
-
1.5
PrintWriter
public PrintWriter(File file)
throws FileNotFoundException
-
Creates a new PrintWriter, without automatic line flushing, with the specified file. This convenience constructor creates the necessary intermediate
OutputStreamWriter
, 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
-
SecurityException
- If a security manager is present and
checkWrite(file.getPath())
denies write access to the file
-
Since:
-
1.5
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 intermediate
OutputStreamWriter
, 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 file
-
SecurityException
- If a security manager is present and
checkWrite(file.getPath())
denies write access to the file
-
UnsupportedEncodingException
- If the named charset is not supported
-
Since:
-
1.5
flush
public void flush()
-
Flush the stream.
-
-
Specified by:
-
flush
in interface
Flushable
-
Specified by:
-
flush
in class
Writer
-
-
See Also:
-
checkError()
close
public void close()
-
Close the stream.
-
-
Specified by:
-
close
in interface
Closeable
-
Specified by:
-
close
in class
Writer
-
-
See Also:
-
checkError()
checkError
public boolean checkError()
-
Flush the stream if it's not closed and check its error state. Errors are cumulative; once the stream encounters an error, this routine will return true on all successive calls.
-
-
Returns:
-
True if the print stream has encountered an error, either on the underlying output stream or during a format conversion.
setError
protected void setError()
-
Indicate that an error has occurred.
-
write
public void write(int c)
-
Write a single character.
-
-
Overrides:
-
write
in class
Writer
-
-
Parameters:
-
c - int specifying a character to be written.
write
public void write(char[] buf,
int off,
int len)
-
Write A Portion of an array of characters.
-
-
Specified by:
-
write
in class
Writer
-
-
Parameters:
-
buf - Array of characters
-
off - Offset from which to start writing characters
-
len - Number of characters to write
write
public void write(char[] buf)
-
Write an array of characters. This method cannot be inherited from the Writer class because it must suppress I/O exceptions.
-
-
Overrides:
-
write
in class
Writer
-
-
Parameters:
-
buf - Array of characters to be written
write
public void write(String s,
int off,
int len)
-
Write a portion of a string.
-
-
Overrides:
-
write
in class
Writer
-
-
Parameters:
-
s - A String
-
off - Offset from which to start writing characters
-
len - Number of characters to write
write
public void write(String s)
-
Write a string. This method cannot be inherited from the Writer class because it must suppress I/O exceptions.
-
-
Overrides:
-
write
in class
Writer
-
-
Parameters:
-
s - String to be written
print
public void print(boolean b)
-
Print a boolean value. The string produced by
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.
-
-
Parameters:
-
b - The boolean to be printed
print
public void print(char c)
-
Print a character. The character is translated into one or more bytes according to the platform's default character encoding, and these bytes are written in exactly the manner of the
write(int)
method.
-
-
Parameters:
-
c - The char to be printed
print
public void print(int i)
-
Print an integer. The string produced by
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.
-
-
Parameters:
-
i - The int to be printed
-
See Also:
-
Integer.toString(int)
print
public void print(long l)
-
Print a long integer. The string produced by
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.
-
-
Parameters:
-
l - The long to be printed
-
See Also:
-
Long.toString(long)
print
public void print(float f)
-
Print a floating-point number. The string produced by
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.
-
-
Parameters:
-
f - The float to be printed
-
See Also:
-
Float.toString(float)
print
public void print(double d)
-
Print a double-precision floating-point number. The string produced by
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.
-
-
Parameters:
-
d - The double to be printed
-
See Also:
-
Double.toString(double)
print
public void print(char[] s)
-
Print an array of characters. The 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.
-
-
Parameters:
-
s - The array of chars to be printed
-
Throws:
-
NullPointerException
- If s is null
print
public void print(String s)
-
Print a string. If the argument is 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.
-
-
Parameters:
-
s - The String to be printed
print
public void print(Object obj)
-
Print an object. The string produced by the
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.
-
-
Parameters:
-
obj - The Object to be printed
-
See Also:
-
Object.toString()
println
public void println()
-
Terminate the current line by writing the line separator string. The line separator string is defined by the system property line.separator, and is not necessarily a single newline character ('\n').
-
println
public void println(boolean x)
-
Print a boolean value and then terminate the line. This method behaves as though it invokes
print(boolean)
and then
println()
.
-
-
Parameters:
-
x - the boolean value to be printed
println
public void println(char x)
-
Print a character and then terminate the line. This method behaves as though it invokes
print(char)
and then
println()
.
-
-
Parameters:
-
x - the char value to be printed
println
public void println(int x)
-
Print an integer and then terminate the line. This method behaves as though it invokes
print(int)
and then
println()
.
-
-
Parameters:
-
x - the int value to be printed
println
public void println(long x)
-
Print a long integer and then terminate the line. This method behaves as though it invokes
print(long)
and then
println()
.
-
-
Parameters:
-
x - the long value to be printed
println
public void println(float x)
-
Print a floating-point number and then terminate the line. This method behaves as though it invokes
print(float)
and then
println()
.
-
-
Parameters:
-
x - the float value to be printed
println
public void println(double x)
-
Print a double-precision floating-point number and then terminate the line. This method behaves as though it invokes
print(double)
and then
println()
.
-
-
Parameters:
-
x - the double value to be printed
println
public void println(char[] x)
-
Print an array of characters and then terminate the line. This method behaves as though it invokes
print(char[])
and then
println()
.
-
-
Parameters:
-
x - the array of char values to be printed
println
public void println(String x)
-
Print a String and then terminate the line. This method behaves as though it invokes
print(String)
and then
println()
.
-
-
Parameters:
-
x - the String value to be printed
println
public void println(Object x)
-
Print an Object and then terminate the line. This method behaves as though it invokes
print(Object)
and then
println()
.
-
-
Parameters:
-
x - the Object value to be printed
printf
public PrintWriter printf(String format,
Object... args)
-
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 invocation
out.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 a
null
argument 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 the
format
is
null
-
Since:
-
1.5
printf
public PrintWriter printf(Locale l,
String format,
Object... args)
-
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 invocation
out.format(l, format, args)
-
-
Parameters:
-
l - The
locale
to apply
during
durring
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
.
-
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 the
format
is
null
-
Since:
-
1.5
format
public PrintWriter format(String format,
Object... args)
-
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 a
null
argument 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 the
format
is
null
-
Since:
-
1.5
format
public PrintWriter format(Locale l,
String format,
Object... args)
-
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
durring
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
.
-
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 the
format
is
null
-
Since:
-
1.5
append
public PrintWriter append(CharSequence csq)
-
Appends the specified character sequence to this writer.
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.
-
-
Specified by:
-
append
in interface
Appendable
-
Overrides:
-
append
in class
Writer
-
-
Parameters:
-
csq - The character sequence to append. If
csq
is
null
, then the four characters
"null"
are appended to this writer.
-
Returns:
-
This writer
-
Since:
-
1.5
append
public PrintWriterappend ( CharSequence csq,
int start,
int end)
-
Appends a subsequence of the specified character sequence to this writer.
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())
-
-
Specified by:
-
append
in interface
Appendable
-
Overrides:
-
append
in class
Writer
-
-
Parameters:
-
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 subsequence
-
end - The index of the character following the last character in the subsequence
-
Returns:
-
This writer
-
Throws:
-
IndexOutOfBoundsException
- If
start
or
end
are negative,
start
is greater than
end
, or
end
is greater than
csq.length()
-
Since:
-
1.5
append
public PrintWriter append(char c)
-
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 invocation
out.write(c)
-
-
Specified by:
-
append
in interface
Appendable
-
Overrides:
-
append
in class
Writer
-
-
Parameters:
-
c - The 16-bit character to append
-
Returns:
-
This writer
-
Since:
-
1.5