PrintStream (Java 2 Platform SE 5.0) (original) (raw)

java.io

Class PrintStream

java.lang.Object java.io.OutputStream java.io.FilterOutputStream java.io.PrintStream

All Implemented Interfaces:

Closeable, Flushable, Appendable

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 anIOException; 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 theprintln 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](../../java/io/PrintWriter.html "class in java.io") class should be used in situations that require writing characters rather than bytes.

Since:

JDK1.0

PrintStream

public PrintStream(OutputStream out)

Create 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.PrintWriter(java.io.OutputStream)

PrintStream

public PrintStream(OutputStream out, boolean autoFlush)

Create 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.PrintWriter(java.io.OutputStream, boolean)](../../java/io/PrintWriter.html#PrintWriter%28java.io.OutputStream, boolean%29)

PrintStream

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

Create 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](../../java/io/UnsupportedEncodingException.html "class in java.io") - If the named encoding is not supported

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 thedefault 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](../../java/io/FileNotFoundException.html "class in java.io") - 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](../../java/lang/SecurityException.html "class in java.lang") - If a security manager is present and checkWrite(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](../../java/io/FileNotFoundException.html "class in java.io") - 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](../../java/lang/SecurityException.html "class in java.lang") - If a security manager is present and checkWrite(fileName) denies write access to the file

[UnsupportedEncodingException](../../java/io/UnsupportedEncodingException.html "class in java.io") - If the named charset is not supported

Since:

1.5

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](../../java/io/FileNotFoundException.html "class in java.io") - 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](../../java/lang/SecurityException.html "class in java.lang") - If a security manager is present and checkWrite(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](../../java/io/FileNotFoundException.html "class in java.io") - 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](../../java/lang/SecurityException.html "class in java.lang") - If a security manager is presentand checkWrite(file.getPath()) denies write access to the file

[UnsupportedEncodingException](../../java/io/UnsupportedEncodingException.html "class in java.io") - If the named charset is not supported

Since:

1.5

flush

public void flush()

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

Specified by:

[flush](../../java/io/Flushable.html#flush%28%29) in interface [Flushable](../../java/io/Flushable.html "interface in java.io")

Overrides:

[flush](../../java/io/FilterOutputStream.html#flush%28%29) in class [FilterOutputStream](../../java/io/FilterOutputStream.html "class in java.io")

See Also:

OutputStream.flush()

close

public void close()

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

Specified by:

[close](../../java/io/Closeable.html#close%28%29) in interface [Closeable](../../java/io/Closeable.html "interface in java.io")

Overrides:

[close](../../java/io/FilterOutputStream.html#close%28%29) in class [FilterOutputStream](../../java/io/FilterOutputStream.html "class in java.io")

See Also:

OutputStream.close()

checkError

public boolean checkError()

Flush the stream and check its error state. The internal error state is set to true when the underlying output stream throws anIOException other than InterruptedIOException, and when the setError method is invoked. If an operation on the underlying output stream throws anInterruptedIOException, 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()

Set the error state of the stream to true.

Since:

JDK1.1

write

public void write(int b)

Write 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](../../java/io/FilterOutputStream.html#write%28int%29) in class [FilterOutputStream](../../java/io/FilterOutputStream.html "class in java.io")

Parameters:

b - The byte to be written

See Also:

print(char), println(char)

write

public void write(byte[] buf, int off, int len)

Write 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](../../java/io/FilterOutputStream.html#write%28byte[], int, int%29) in class [FilterOutputStream](../../java/io/FilterOutputStream.html "class in java.io")

Parameters:

buf - A byte array

off - Offset from which to start taking bytes

len - Number of bytes to write

See Also:

FilterOutputStream.write(int)

print

public void print(boolean b)

Print a boolean value. The string produced by [String.valueOf(boolean)](../../java/lang/String.html#valueOf%28boolean%29) 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)](../../java/io/PrintStream.html#write%28int%29) 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)](../../java/io/PrintStream.html#write%28int%29) method.

Parameters:

c - The char to be printed

print

public void print(int i)

Print an integer. The string produced by [String.valueOf(int)](../../java/lang/String.html#valueOf%28int%29) 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)](../../java/io/PrintStream.html#write%28int%29) 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)](../../java/lang/String.html#valueOf%28long%29) 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)](../../java/io/PrintStream.html#write%28int%29) 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)](../../java/lang/String.html#valueOf%28float%29) 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)](../../java/io/PrintStream.html#write%28int%29) 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)](../../java/lang/String.html#valueOf%28double%29) 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)](../../java/io/PrintStream.html#write%28int%29) 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)](../../java/io/PrintStream.html#write%28int%29) method.

Parameters:

s - The array of chars to be printed

Throws:

[NullPointerException](../../java/lang/NullPointerException.html "class in java.lang") - 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)](../../java/io/PrintStream.html#write%28int%29) 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)](../../java/lang/String.html#valueOf%28java.lang.Object%29) 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)](../../java/io/PrintStream.html#write%28int%29) 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 propertyline.separator, and is not necessarily a single newline character ('\n').

println

public void println(boolean x)

Print a boolean and then terminate the line. This method behaves as though it invokes [print(boolean)](../../java/io/PrintStream.html#print%28boolean%29) and then[println()](../../java/io/PrintStream.html#println%28%29).

Parameters:

x - The boolean 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)](../../java/io/PrintStream.html#print%28char%29) and then[println()](../../java/io/PrintStream.html#println%28%29).

Parameters:

x - The char 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)](../../java/io/PrintStream.html#print%28int%29) and then[println()](../../java/io/PrintStream.html#println%28%29).

Parameters:

x - The int to be printed.

println

public void println(long x)

Print a long and then terminate the line. This method behaves as though it invokes [print(long)](../../java/io/PrintStream.html#print%28long%29) and then[println()](../../java/io/PrintStream.html#println%28%29).

Parameters:

x - a The long to be printed.

println

public void println(float x)

Print a float and then terminate the line. This method behaves as though it invokes [print(float)](../../java/io/PrintStream.html#print%28float%29) and then[println()](../../java/io/PrintStream.html#println%28%29).

Parameters:

x - The float to be printed.

println

public void println(double x)

Print a double and then terminate the line. This method behaves as though it invokes [print(double)](../../java/io/PrintStream.html#print%28double%29) and then[println()](../../java/io/PrintStream.html#println%28%29).

Parameters:

x - The double 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[])](../../java/io/PrintStream.html#print%28char[]%29) and then [println()](../../java/io/PrintStream.html#println%28%29).

Parameters:

x - an array of chars to print.

println

public void println(String x)

Print a String and then terminate the line. This method behaves as though it invokes [print(String)](../../java/io/PrintStream.html#print%28java.lang.String%29) and then[println()](../../java/io/PrintStream.html#println%28%29).

Parameters:

x - The String 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)](../../java/io/PrintStream.html#print%28java.lang.Object%29) and then[println()](../../java/io/PrintStream.html#println%28%29).

Parameters:

x - The Object 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](../../java/lang/NullPointerException.html "class in java.lang") - If the format is null

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. 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 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](../../java/lang/NullPointerException.html "class in java.lang") - If the format is null

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(), 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](../../java/lang/NullPointerException.html "class in java.lang") - If the format is null

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. 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 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](../../java/lang/NullPointerException.html "class in java.lang") - If the format is null

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. 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](../../java/lang/Appendable.html#append%28java.lang.CharSequence%29) in interface [Appendable](../../java/lang/Appendable.html "interface in java.lang")

Parameters:

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

Returns:

This character 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](../../java/lang/Appendable.html#append%28java.lang.CharSequence, int, int%29) in interface [Appendable](../../java/lang/Appendable.html "interface in java.lang")

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 character stream

Throws:

[IndexOutOfBoundsException](../../java/lang/IndexOutOfBoundsException.html "class in java.lang") - If start or end are negative, start is greater than end, or end 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](../../java/lang/Appendable.html#append%28char%29) in interface [Appendable](../../java/lang/Appendable.html "interface in java.lang")

Parameters:

c - The 16-bit character to append

Returns:

This output stream

Since:

1.5

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

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