Class PrintStream
- java.lang.Object
-
- java.io.OutputStream
-
- java.io.FilterOutputStream
-
- java.io.PrintStream
- All Implemented Interfaces:
-
Closeable
,Flushable
,Appendable
,AutoCloseable
- Direct Known Subclasses:
LogStream
public class PrintStream extends FilterOutputStream implements Appendable, Closeable
A 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 given encoding or charset, or platform's default character encoding 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
Field Summary
Fields declared in class java.io.FilterOutputStream
out
Constructor Summary
Constructor | 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(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. |
PrintStream(OutputStream out,
boolean autoFlush) | Creates a new print stream. |
PrintStream(OutputStream out,
boolean autoFlush,
String encoding) | Creates a new print stream. |
PrintStream(OutputStream out,
boolean autoFlush,
Charset charset) | Creates a new print stream, with the specified OutputStream, automatic 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 Type | Method | 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(String format,
Object... args) | Writes a formatted string to this output stream using the specified format string and arguments. |
PrintStream | format(Locale l,
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(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(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. |
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 |
void | write(byte[] buf,
int off,
int len) | Writes |
void | write(int b) | Writes the specified byte to this stream. |
Methods declared in class java.io.FilterOutputStream
write
Methods declared in class java.io.OutputStream
nullOutputStream
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
PrintStream
public PrintStream(OutputStream out)
Creates a new print stream. This stream will not flush automatically.
- Parameters:
-
out
- The output stream to which values and objects will be printed - See Also:
PrintWriter(java.io.OutputStream)
PrintStream
public PrintStream(OutputStream out, boolean autoFlush)
Creates a new print stream.
- Parameters:
-
out
- The output stream to which values and objects will be printed -
autoFlush
- A boolean; if true, 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:
PrintWriter(java.io.OutputStream, boolean)
PrintStream
public PrintStream(OutputStream out, boolean autoFlush, String encoding) throws UnsupportedEncodingException
Creates a new print stream.
- Parameters:
-
out
- The output stream to which values and objects will be printed -
autoFlush
- A boolean; if true, 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 -
encoding
- The name of a supported character encoding - Throws:
-
UnsupportedEncodingException
- If the named encoding is not supported - Since:
- 1.4
PrintStream
public PrintStream(OutputStream out, boolean autoFlush, Charset charset)
Creates a new print stream, with the specified OutputStream, automatic line flushing and charset. This convenience constructor creates the necessary intermediate OutputStreamWriter
, which will encode characters using the provided charset.
- Parameters:
-
out
- The output stream to which values and objects will be printed -
autoFlush
- A boolean; if true, 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 -
charset
- A charset - Since:
- 10
PrintStream
public PrintStream(String fileName) throws FileNotFoundException
Creates a new print stream, 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 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 file -
SecurityException
- If a security manager is present andcheckWrite(fileName)
denies write access to the file - Since:
- 1.5
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 intermediate OutputStreamWriter
, 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 file -
SecurityException
- If a security manager is present andcheckWrite(fileName)
denies write access to the file -
UnsupportedEncodingException
- If the named charset is not supported - Since:
- 1.5
PrintStream
public PrintStream(String fileName, Charset charset) throws IOException
Creates a new print stream, 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 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 file -
SecurityException
- If a security manager is present andcheckWrite(fileName)
denies write access to the file - Since:
- 10
PrintStream
public PrintStream(File file) throws FileNotFoundException
Creates a new print stream, 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 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 file -
SecurityException
- If a security manager is present andcheckWrite(file.getPath())
denies write access to the file - Since:
- 1.5
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 intermediate OutputStreamWriter
, 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 file -
SecurityException
- If a security manager is present andcheckWrite(file.getPath())
denies write access to the file -
UnsupportedEncodingException
- If the named charset is not supported - Since:
- 1.5
PrintStream
public PrintStream(File file, Charset charset) throws IOException
Creates a new print stream, 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 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 file -
SecurityException
- If a security manager is present andcheckWrite(file.getPath())
denies write access to the file - Since:
- 10
Method Detail
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:
OutputStream.flush()
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:
OutputStream.close()
checkError
public boolean checkError()
Flushes the stream and checks its error state. The internal error state is set to 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.
- Returns:
-
true
if and only if this stream has encountered anIOException
other thanInterruptedIOException
, or thesetError
method has been invoked
setError
protected void setError()
Sets the error state of the stream to true
.
This method will cause subsequent invocations of checkError()
to return true
until clearError()
is invoked.
- Since:
- 1.1
clearError
protected void clearError()
Clears the internal error state of this stream.
This method will cause subsequent invocations of checkError()
to return false
until another write operation fails and invokes setError()
.
- 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 the 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.
- Overrides:
-
write
in classFilterOutputStream
- Parameters:
-
b
- The byte to be written - See Also:
-
print(char)
,println(char)
write
public void write(byte[] buf, int off, int len)
Writes 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.
- Overrides:
-
write
in classFilterOutputStream
- Parameters:
-
buf
- A byte array -
off
- Offset from which to start taking bytes -
len
- Number of bytes to write - See Also:
FilterOutputStream.write(int)
public void print(boolean b)
Prints 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
- Theboolean
to be printed
public void print(char c)
Prints 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
- Thechar
to be printed
public void print(int i)
Prints 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
- Theint
to be printed - See Also:
Integer.toString(int)
public void print(long l)
Prints 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
- Thelong
to be printed - See Also:
Long.toString(long)
public void print(float f)
Prints 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
- Thefloat
to be printed - See Also:
Float.toString(float)
public void print(double d)
Prints 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
- Thedouble
to be printed - See Also:
Double.toString(double)
public void print(char[] s)
Prints 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
- Ifs
isnull
public void print(String s)
Prints 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
- TheString
to be printed
public void print(Object obj)
Prints 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
- TheObject
to be printed - See Also:
Object.toString()
println
public void println()
Terminates 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)
Prints a boolean and then terminate the line. This method behaves as though it invokes print(boolean)
and then println()
.
- Parameters:
-
x
- Theboolean
to be printed
println
public void println(char x)
Prints a character and then terminate the line. This method behaves as though it invokes print(char)
and then println()
.
- Parameters:
-
x
- Thechar
to be printed.
println
public void println(int x)
Prints an integer and then terminate the line. This method behaves as though it invokes print(int)
and then println()
.
- Parameters:
-
x
- Theint
to be printed.
println
public void println(long x)
Prints a long and then terminate the line. This method behaves as though it invokes print(long)
and then println()
.
- Parameters:
-
x
- a Thelong
to be printed.
println
public void println(float x)
Prints a float and then terminate the line. This method behaves as though it invokes print(float)
and then println()
.
- Parameters:
-
x
- Thefloat
to be printed.
println
public void println(double x)
Prints a double and then terminate the line. This method behaves as though it invokes print(double)
and then println()
.
- Parameters:
-
x
- Thedouble
to be printed.
println
public void println(char[] x)
Prints an array of characters and then terminate the line. This method behaves as though it invokes print(char[])
and then println()
.
- Parameters:
-
x
- an array of chars to print.
println
public void println(String x)
Prints a String and then terminate the line. This method behaves as though it invokes print(String)
and then println()
.
- Parameters:
-
x
- TheString
to be printed.
println
public void println(Object x)
Prints an Object and then terminate the line. This method calls at first String.valueOf(x) to get the printed object's string value, then behaves as though it invokes print(String)
and then println()
.
- Parameters:
-
x
- TheObject
to be printed.
printf
public 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.
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 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
public 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.
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 formatting. Ifl
isnull
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 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
public PrintStream format(String format, Object... args)
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)
with FORMAT
category specified, 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 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
public PrintStream format(Locale l, String format, Object... args)
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 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 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
public PrintStream append(CharSequence csq)
Appends the specified character sequence to this output stream.
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.
- 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
public PrintStream append(CharSequence csq, int start, int end)
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)
when csq
is not null
, behaves in exactly the same way as the invocation
out.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 subsequence -
end
- 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
public PrintStream append(char c)
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 invocation
out.print(c)
- Specified by:
-
append
in interfaceAppendable
- Parameters:
-
c
- The 16-bit character to append - Returns:
- This output stream
- Since:
- 1.5