public class PrintWriter
extends java.io.Writer
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()
.
Modifier and Type | Field and Description |
---|---|
protected java.io.Writer |
out
The underlying character-output stream of this
PrintWriter . |
Constructor and Description |
---|
PrintWriter(java.io.OutputStream out)
Creates a new PrintWriter, without automatic line flushing, from an existing OutputStream.
|
PrintWriter(java.io.OutputStream out,
boolean autoFlush)
Creates a new PrintWriter from an existing OutputStream.
|
PrintWriter(java.io.Writer out)
Creates a new PrintWriter, without automatic line flushing.
|
PrintWriter(java.io.Writer out,
boolean autoFlush)
Creates a new PrintWriter.
|
Modifier and Type | Method and Description |
---|---|
PrintWriter |
append(char c)
Appends the specified character to this writer.
|
PrintWriter |
append(java.lang.CharSequence csq)
Appends the specified character sequence to this writer.
|
PrintWriter |
append(java.lang.CharSequence csq,
int start,
int end)
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.
|
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(java.lang.Object obj)
Prints an object.
|
void |
print(java.lang.String s)
Prints a string.
|
void |
println()
Terminates the current line by writing the line separator string.
|
void |
println(boolean x)
Prints a boolean value 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-precision floating-point number and then terminates the line.
|
void |
println(float x)
Prints a floating-point number and then terminates the line.
|
void |
println(int x)
Prints an integer and then terminates the line.
|
void |
println(long x)
Prints a long integer and then terminates the line.
|
void |
println(java.lang.Object x)
Prints an Object and then terminates the line.
|
void |
println(java.lang.String x)
Prints a String and then terminates the line.
|
protected void |
setError()
Indicates that an error has occurred.
|
void |
write(char[] buf)
Writes an array of characters.
|
void |
write(char[] buf,
int off,
int len)
Writes A Portion of an array of characters.
|
void |
write(int c)
Writes a single character.
|
void |
write(java.lang.String s)
Writes a string.
|
void |
write(java.lang.String s,
int off,
int len)
Writes a portion of a string.
|
@Nullable protected java.io.Writer out
PrintWriter
.public PrintWriter(java.io.Writer out)
out
- A character-output streampublic PrintWriter(java.io.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(java.io.OutputStream out)
out
- An output streamOutputStreamWriter.OutputStreamWriter(java.io.OutputStream)
public PrintWriter(java.io.OutputStream out, boolean autoFlush)
out
- An output streamautoFlush
- A boolean; if true, the println, printf, or format methods will flush the
output bufferOutputStreamWriter.OutputStreamWriter(java.io.OutputStream)
public void flush()
flush
in interface java.io.Flushable
flush
in class java.io.Writer
checkError()
public void close()
close
in interface java.io.Closeable
close
in interface java.lang.AutoCloseable
close
in class java.io.Writer
checkError()
public boolean checkError()
true
if the print stream has encountered an error, either on the underlying output stream or
during a format conversion.protected void setError()
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)
write
in class java.io.Writer
c
- int specifying a character to be written.public void write(char[] buf, int off, int len)
write
in class java.io.Writer
buf
- Array of charactersoff
- Offset from which to start writing characterslen
- Number of characters to writepublic void write(char[] buf)
write
in class java.io.Writer
buf
- Array of characters to be writtenpublic void write(java.lang.String s, int off, int len)
write
in class java.io.Writer
s
- A Stringoff
- Offset from which to start writing characterslen
- Number of characters to writepublic void write(java.lang.String s)
write
in class java.io.Writer
s
- String to be writtenpublic 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 printedjava.lang.NullPointerException
- If s
is null
public void print(@Nullable java.lang.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(java.lang.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
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(java.lang.String x)
print(String)
and then println()
.x
- the String
value to be printedpublic void println(java.lang.Object x)
print(String)
and then
println()
.x
- The Object
to be printed.public PrintWriter append(@Nullable java.lang.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 java.lang.Appendable
append
in class java.io.Writer
csq
- The character sequence to append. If csq is null, then the four characters
"null" are appended to this writer.public PrintWriter append(@Nullable java.lang.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 java.lang.Appendable
append
in class java.io.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 subsequencejava.lang.IndexOutOfBoundsException
- 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 java.lang.Appendable
append
in class java.io.Writer
c
- The 16-bit character to append