system.in

问题 InputStream is an Abstract class.Then how are we able to access System.in.And moreover int read() is an abstract method in InputStream class.Then how are we able to access System.in.read() method if read() is an abstract method. Like int a=System.in.read(); System.out.println((char)a); 回答1: I suggest you to read more about abstraction and inheritance methods in Java. If you extend an abstract class, you have to implement its abstract methods. This way, you provide an implementation for it,

问题 InputStream is an Abstract class.Then how are we able to access System.in.And moreover int read() is an abstract method in InputStream class.Then how are we able to access System.in.read() method if read() is an abstract method. Like int a=System.in.read(); System.out.println((char)a); 回答1: I suggest you to read more about abstraction and inheritance methods in Java. If you extend an abstract class, you have to implement its abstract methods. This way, you provide an implementation for it,

问题 If I start reading from System.in , it will block the thread until it gets data. There is no way to stop it. Here are all the ways that I've tried: Interrupting the thread Stopping the thread Closing System.in Calling System.exit(0) does indeed stop the thread, but it also kills my application so not ideal. Entering a char into the console makes the method return, but I can't rely on user input. Sample code that does not work: public static void main(String[] args) throws InterruptedException

问题 package sandbox2; import java.util.Scanner; public class Sandbox2 { public static void main(String[] args) { for (int i = 0; i < 5; i++) { String s = askForProperty("Enter value for " + i + ": "); System.out.println(i + " is: " + s); } } private static String askForProperty(String message) { Scanner keyboard = new Scanner(System.in); System.out.print(message); String s = keyboard.nextLine(); keyboard.close(); return s; } } When i run the above code, it returns the first response PERFECTLY.

问题 Is it possible for Eclipse to read stdin from a file? 回答1: Pure Java You can redirect System.in with a single line of code: System.setIn(new FileInputStream(filename)); See System.setIn(). Eclipse config In Eclipse 4.5 or later, the launch configuration dialog can set System.in to read from a file. See the announcement here. 回答2: [Update] As it has been pointed out in the comments, this answer was misleading so I have updated it to correct the errors. [/Update] On bash or command prompt you

问题 Here's the code: package testpack; import java.io.*; public class InputStreamReadDemo { private void readByte() throws IOException { System.out.print("Enter the byte of data that you want to be read: "); int a = System.in.read(); System.out.println("The first byte of data that you inputted corresponds to the binary value "+Integer.toBinaryString(a)+" and to the integer value "+a+"."); // tried writing System.in.close(); and System.in.reset(); } private void readLine() throws IOException {

问题 This question already has answers here : How to get SelectableChannel from an InputStream? (2 answers) Closed 3 years ago . Is it possible to use NIO with System.in? I would like to somehow treat 'stdin' as a selectable channel. Has anyone found a way to do this? 回答1: duplicate: How to get SelectableChannel from an InputStream? hmmm... on second thought, for stdin there may be a solution. I found this reference: http://www.javafaq.nu/java-example-code-346.html and in particular: SystemInPipe

问题 This question already has answers here : How to get SelectableChannel from an InputStream? (2 answers) Closed 3 years ago . Is it possible to use NIO with System.in? I would like to somehow treat 'stdin' as a selectable channel. Has anyone found a way to do this? 回答1: duplicate: How to get SelectableChannel from an InputStream? hmmm... on second thought, for stdin there may be a solution. I found this reference: http://www.javafaq.nu/java-example-code-346.html and in particular: SystemInPipe

问题 I am just a newbie in Java. I was wondering the way System.out.println() is used. Out is a static field inside System class. The type of out is PrintStream . But when I saw the constructor of PrintStream class, it takes a parameter of type OutputStream and as far as I know we cannot create the object of an abstract class. In that case we must pass some subclass's object to the constructor of PrintStream . What is that class? Same is the System.in . It is also InputStream 's reference but what

问题 I have a scanner that takes user input until ctrl+d and then a while loop which adds each word to a string and then prints it, but i'd like to know how to also include the new line indicators like \n in the string wherever there is a new line. Scanner sc = new Scanner(System.in); System.out.println("Enter your string: "); String x = ""; while (sc.hasNext()){ x+=sc.next() +" "; } System.out.println(x); E.g this code would take the input: Hello Hello Hello and print: Hello Hello Hello Whereas I