Class IO
java.lang.Object
java.io.IO
IO is a preview API of the Java platform.
Preview features may be removed in a future release, or upgraded to permanent features of the Java platform.
A collection of static convenience methods that provide access to
system console for implicitly declared classes.
Each of this class' methods throws IOError if the system console
is null; otherwise, the effect is as if a similarly-named method
had been called on that console.
Input and output from methods in this class use the character set of
the system console as specified by Console.charset().
- Since:
- 23
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Method Summary
Modifier and TypeMethodDescriptionstatic voidWrites a string representation of the specified object to the system console and then flushes that console.static voidprintln()Terminates the current line on the system console and then flushes that console.static voidWrites a string representation of the specified object to the system console, terminates the line and then flushes that console.static Stringreadln()Reads a single line of text from the system console.static StringWrites a prompt as if by callingprint, then reads a single line of text from the system console.
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Method Details
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println
Writes a string representation of the specified object to the system console, terminates the line and then flushes that console.The effect is as if
println(obj)PREVIEW had been called onSystem.console().- Parameters:
obj- the object to print, may benull- Throws:
IOError- ifSystem.console()returnsnull, or if an I/O error occurs
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println
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print
Writes a string representation of the specified object to the system console and then flushes that console.The effect is as if
print(obj)PREVIEW had been called onSystem.console().- Parameters:
obj- the object to print, may benull- Throws:
IOError- ifSystem.console()returnsnull, or if an I/O error occurs
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readln
Writes a prompt as if by callingprint, then reads a single line of text from the system console.The effect is as if
readln(prompt)PREVIEW had been called onSystem.console().- Parameters:
prompt- the prompt string, may benull- Returns:
- a string containing the line read from the system console, not
including any line-termination characters. Returns
nullif an end of stream has been reached without having read any characters. - Throws:
IOError- ifSystem.console()returnsnull, or if an I/O error occurs
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readln
Reads a single line of text from the system console.The effect is as if
readln()PREVIEW had been called onSystem.console().- Returns:
- a string containing the line read from the system console, not
including any line-termination characters. Returns
nullif an end of stream has been reached without having read any characters. - Throws:
IOError- ifSystem.console()returnsnull, or if an I/O error occurs- Since:
- 24
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IOwhen preview features are enabled.