Un PrintStream aggiunge funzionalità a un altro flusso di output, ovvero la capacità di stampare comodamente rappresentazioni di vari valori di dati. A differenza di altri flussi di output, PrintStream non genera mai una IOException; situazioni eccezionali invece impostano semplicemente un flag interno che può essere testato tramite il metodo checkError. Facoltativamente è possibile creare un PrintStream in modo da eseguire lo svuotamento automatico. Tutti i caratteri stampati da PrintStream vengono convertiti in byte utilizzando la codifica dei caratteri predefinita della piattaforma. La classe PrintWriter deve essere utilizzata in situazioni che richiedono la scrittura di caratteri anziché di byte. Dichiarazione di classe
public class PrintStream extends FilterOutputStream implements Appendable Closeable
Campo
protected OutputStream out:This is the output stream to be filtered.
Costruttori e descrizione
PrintStream(File):
Crea un nuovo flusso di stampa senza svuotamento automatico della riga con il file specificato.
PrintStream(File file String csn):
Crea un nuovo flusso di stampa senza svuotamento automatico della riga con il file e il set di caratteri specificati.
PrintStream(OutputStream in uscita):
Crea un nuovo flusso di stampa.
PrintStream(OutputStream out booleano autoFlush) :
Crea un nuovo flusso di stampa.
PrintStream (OutputStream out codifica booleana autoFlush String)
: crea un nuovo flusso di stampa.
PrintStream(String nomefile):
Crea un nuovo flusso di stampa senza svuotamento automatico della riga con il nome file specificato.
PrintStream(String fileName String csn):
Crea un nuovo flusso di stampa senza svuotamento automatico della riga con il nome file e il set di caratteri specificati. Metodi:
PrintStream append(char c):
Appends the specified character to this output stream.
Syntax : public PrintStream append(char c) Parameters: c - The 16-bit character to append Returns: This output stream
PrintStream append(CharSequence csq int start int end):
Appends the specified character sequence to this output stream.
Syntax : public PrintStream append(CharSequence csq int start int end) Parameters: csq - The character sequence from which a subsequence will be appended. 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
Aggiungi PrintStream (CharSequence csq):
Appends a subsequence of the specified character sequence to this output stream.
Syntax : public PrintStream append(CharSequence csq) Parameters: csq - The character sequence to append. Returns: This output stream
booleano checkError():
Flushes the stream and checks its error state.
Syntax : public boolean checkError() Returns: true if and only if this stream has encountered an IOException other than InterruptedIOException or the setError method has been invoked
protetto void clearError() :
Clears the internal error state of this stream.
Syntax : protected void clearError()
vuoto vicino() :
Closes the stream.
Syntax : public void close() Overrides: close in class FilterOutputStream
svuotamento():
Flushes the stream.
Syntax : public void flush() Overrides: flush in class FilterOutputStream
Writes a formatted string to this output stream using the specified format string and arguments.
Syntax : public PrintStream format(Locale l String format Object... 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. The number of arguments is variable and may be zero. Returns: This output stream Throws: IllegalFormatException NullPointerException
Writes a formatted string to this output stream using the specified format string and arguments.
Syntax : public PrintStream format(String format Object... args) Parameters : format - A format string as described in Format string syntax args - Arguments referenced by the format specifiers in the format string. The number of arguments is variable and may be zero. Returns: This output stream Throws: IllegalFormatException NullPointerException
void print(booleano b):
Prints a boolean value.
Syntax : public void print(boolean b)
stampa vuota(carattere c):
Prints a character.
Syntax : public void print(char c)
void print(char[] s):
Prints an array of characters.
Syntax : public void print(char[] s)
stampa vuota(doppia d):
Prints a double-precision floating-point number.
Syntax : public void print(double b)
stampa vuota(float f):
Prints a floating-point number.
Syntax : public void print(float f)
void print(int i):
Prints an integer.
Syntax : public void print(int i)
stampa vuota(lunga l):
Prints a long integer.
Syntax : public void print(long l)
void print(Oggetto oggetto):
Prints an object.
Syntax : public void print(Object obj)
stampa nulla(Stringa s):
Prints a string.
Syntax : public void print(String s)
Java
importjava.io.FileNotFoundException;importjava.io.FileOutputStream;importjava.io.PrintStream;importjava.util.Locale;//Java program to demonstrate PrintStream methodsclassPrintstream{publicstaticvoidmain(Stringargs[])throwsFileNotFoundException{FileOutputStreamfout=newFileOutputStream('file.txt');//creating Printstream objPrintStreamout=newPrintStream(fout);Strings='First';//writing to file.txtcharc[]={'G''E''E''K'};//illustrating print(boolean b) methodout.print(true);//illustrating print(int i) methodout.print(1);//illustrating print(float f) methodout.print(4.533f);//illustrating print(String s) methodout.print('GeeksforGeeks');out.println();//illustrating print(Object Obj) methodout.print(fout);out.println();//illustrating append(CharSequence csq) methodout.append('Geek');out.println();//illustrating checkError() methodout.println(out.checkError());//illustrating format() methodout.format(Locale.UK'Welcome to my %s program's);//illustrating flush methodout.flush();//illustrating close methodout.close();}}
Note: The output might not be visible on online IDE as it is not able to read the file. Produzione:
true14.533GeeksforGeeks java.io.FileOutputStream@1540e19dGeek false Welcome to my First program
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