java.io.PrintStream

public class java.io

PrintStream

Java SE 6

Extends: OutputStream > FilterOutputStream

Extended by: LogStream

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 platform's default character encoding. The PrintWriter class should be used in situations that require writing characters rather than bytes.

version 1.40, 06/06/28

since JDK1.0

Constructors

public

PrintStream(OutputStream out) Details

Creates a new print stream. This stream will not flush automatically.

out	The output stream to which values and objects will be printed
See also	PrintWriter(java.io.OutputStream)

public

PrintStream(OutputStream out, boolean autoFlush) Details

Creates a new print stream.

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 the `println` methods is invoked, or a newline character or byte (`'\n'`) is written
See also	PrintWriter(java.io.OutputStream, boolean)

public

PrintStream(OutputStream out, boolean autoFlush, String encoding) throws UnsupportedEncodingException Details

Creates a new print stream.

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 the `println` 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

public

PrintStream(String fileName) throws FileNotFoundException Details

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.

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
Throws	SecurityException: If a security manager is present and `checkWrite(fileName)` denies write access to the file
since	1.5

public

PrintStream(String fileName, String csn) throws FileNotFoundException, UnsupportedEncodingException Details

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.

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
Throws	SecurityException: If a security manager is present and `checkWrite(fileName)` denies write access to the file
Throws	UnsupportedEncodingException: If the named charset is not supported
since	1.5

public

PrintStream(File file) throws FileNotFoundException Details

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.

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
Throws	SecurityException: If a security manager is present and `checkWrite(file.getPath())` denies write access to the file
since	1.5

public

PrintStream(File file, String csn) throws FileNotFoundException, UnsupportedEncodingException Details

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.

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
Throws	SecurityException: If a security manager is presentand `checkWrite(file.getPath())` denies write access to the file
Throws	UnsupportedEncodingException: If the named charset is not supported
since	1.5

Methods

public PrintStream

append(CharSequence csq) Details

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.

csq The character sequence to append. If csq is null, then the four characters "null" are appended to this output stream.

return This output stream

since 1.5

public PrintStream

append(CharSequence csq, int start, int end) Details

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())

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
return	This output stream
Throws	IndexOutOfBoundsException: If `start` or `end` are negative, `start` is greater than `end`, or `end` is greater than `csq.length()`
since	1.5

public PrintStream

append(char c) Details

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)

c	The 16-bit character to append
return	This output stream
since	1.5

public boolean

checkError() Details

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.

return true if and only if this stream has encountered an IOException other than InterruptedIOException, or the setError method has been invoked

protected void

clearError() Details

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

public void

close() Details

Closes the stream. This is done by flushing the stream and then closing the underlying output stream.

See also

close()

public void

flush() Details

Flushes the stream. This is done by writing any buffered output bytes to the underlying output stream and then flushing that stream.

See also

flush()

public PrintStream

format(String format, Object[] args) Details

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(), regardless of any previous invocations of other formatting methods on this object.

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.

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.

Throws NullPointerException: If the format is null

return This output stream

since 1.5

public PrintStream

format(Locale l, String format, Object[] args) Details

Writes a formatted string to this output stream using the specified format string and arguments.

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 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.
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.
Throws	NullPointerException: If the `format` is `null`
return	This output stream
since	1.5

public void

print(boolean b) Details

Prints a boolean value. The string produced by java.lang.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 printed

public void

print(char c) Details

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.

c	The `char` to be printed

public void

print(int i) Details

Prints an integer. The string produced by java.lang.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 printed
See also	toString(int)

public void

print(long l) Details

Prints a long integer. The string produced by java.lang.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 printed
See also	toString(long)

public void

print(float f) Details

Prints a floating-point number. The string produced by java.lang.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 printed
See also	toString(float)

public void

print(double d) Details

Prints a double-precision floating-point number. The string produced by java.lang.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 printed
See also	toString(double)

public void

print(char[] s) Details

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.

s	The array of chars to be printed
Throws	NullPointerException: If `s` is `null`

public void

print(String s) Details

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.

s	The `String` to be printed

public void

print(Object obj) Details

Prints an object. The string produced by the java.lang.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 printed
See also	toString()

public PrintStream

printf(String format, Object[] args) Details

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)

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.
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.
Throws	NullPointerException: If the `format` is `null`
return	This output stream
since	1.5

public PrintStream

printf(Locale l, String format, Object[] args) Details

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)

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 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.
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.
Throws	NullPointerException: If the `format` is `null`
return	This output stream
since	1.5

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').

public void

println(boolean x) Details

Prints a boolean and then terminate the line. This method behaves as though it invokes #print(boolean) and then #println().

x	The `boolean` to be printed

public void

println(char x) Details

Prints a character and then terminate the line. This method behaves as though it invokes #print(char) and then #println().

x	The `char` to be printed.

public void

println(int x) Details

Prints an integer and then terminate the line. This method behaves as though it invokes #print(int) and then #println().

x	The `int` to be printed.

public void

println(long x) Details

Prints a long and then terminate the line. This method behaves as though it invokes #print(long) and then #println().

x	a The `long` to be printed.

public void

println(float x) Details

Prints a float and then terminate the line. This method behaves as though it invokes #print(float) and then #println().

x	The `float` to be printed.

public void

println(double x) Details

Prints a double and then terminate the line. This method behaves as though it invokes #print(double) and then #println().

x	The `double` to be printed.

public void

println(char[] x) Details

Prints an array of characters and then terminate the line. This method behaves as though it invokes #print(char[]) and then #println().

x	an array of chars to print.

public void

println(String x) Details

Prints a String and then terminate the line. This method behaves as though it invokes #print(String) and then #println().

x	The `String` to be printed.

public void

println(Object x) Details

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().

x	The `Object` to be printed.

public void

write(int b) Details

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.

b The byte to be written

See also print(char), println(char)

public void

write(byte[] buf, int off, int len) Details

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.

buf A byte array

off Offset from which to start taking bytes

len Number of bytes to write

Properties

protected void

setError() Details

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 JDK1.1

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Java SE 6