What is java io printstream

What is java io printstream

Если стерли изначальную System.in. Просто перезагрузите программу. Или передайте самый примитивный поток читающие байты или вот что у меня по дефолту

 InputStream s = System.in; System.out.println(s.getClass()); Вывод: class java.io.BufferedInputStream 

Я ведь не один до сих пор всегда когда нужно ввести что-нибудь с консоли использую Scanner? В этом ведь нет ничего плохого? Я просто не понимаю зачем писать больше кода 🤔

Я немного не понимаю, зачем нам менять поток System.in на чтение из строк, если мы можем по другому считать строки? Что нам даёт System.in?

 public void stream() < String str = "Привет! Меня зовут Амиго!\\nЯ изучаю Java на сайте JavaRush.\\nОднажды я стану крутым программистом!\\n\""; byte[] arrByte = str.getBytes(); try(InputStream is = new ByteArrayInputStream(arrByte); BufferedReader br = new BufferedReader(new InputStreamReader(is)))< while((str = br.readLine())!= null)< System.out.println(str); >>catch (FileNotFoundException e)< >catch (IOException e) < >> 

Тут не точно > . мы как бы оставляем для этой информации «свободное место» с помощью указателей %s и %d Я про слово — указатели Согласно этому The printf and format Methods это не «указатели», а > which are special characters that format the arguments of Object. args. (The notation Object. args is called varargs, which means that the number of arguments may vary.)

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What is java io printstream

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.

Field Summary

Fields inherited from class java.io.FilterOutputStream

Constructor Summary

Creates a new print stream, without automatic line flushing, with the specified file name and charset.

Method Summary

A convenience method to write a formatted string to this output stream using the specified format string and arguments.

A convenience method to write a formatted string to this output stream using the specified format string and arguments.

Methods inherited from class java.io.FilterOutputStream

Methods inherited from class java.lang.Object

Constructor Detail

PrintStream

PrintStream

PrintStream

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

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.

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.

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.

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.

Method Detail

flush

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

close

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

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();

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.

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() .

write

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.

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.

print

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.

print

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.

print

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.

print

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.

print

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.

print

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.

print

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.

print

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.

print

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.

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() .

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() .

println

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

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() .

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() .

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() .

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() .

println

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

println

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() .

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

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

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.

format

public PrintStream format(Locale l, String format, Object. args)

append

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

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.

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())

append

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

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