Scanner method to get a char

问题

What is the Scanner method to get a char returned by the keyboard in Java.

like nextLine() for String, nextInt() for int, etc.

回答1:

To get a char from a Scanner, you can use the findInLine method.

    Scanner sc = new Scanner("abc");
    char ch = sc.findInLine(".").charAt(0);
    System.out.println(ch); // prints "a"
    System.out.println(sc.next()); // prints "bc"

If you need a bunch of char from a Scanner, then it may be more convenient to (perhaps temporarily) change the delimiter to the empty string. This will make next() returns a length-1 string every time.

    Scanner sc = new Scanner("abc");
    sc.useDelimiter("");
    while (sc.hasNext()) {
        System.out.println(sc.next());
    } // prints "a", "b", "c"

回答2:

You can use the Console API (which made its appearance in Java 6) as follows:

Console cons = System.console();
if(cons != null) {
  char c = (char) cons.reader().read();  // Checking for EOF omitted
  ...
}

If you just need a single line you don't even need to go through the reader object:

String s = cons.readLine();

回答3:

Java's Scanner class does not have a built in method to read from a Scanner character-by-character.

http://java.sun.com/javase/6/docs/api/java/util/Scanner.html

However, it should still be possible to fetch individual characters from the Scanner as follows:

Scanner sc:

char c = sc.findInLine(".").charAt(0);

And you could use it to fetch each character in your scanner like this:

while(sc.hasNext()){
    char c = sc.findInLine(".").charAt(0);
    System.out.println(c); //to print out every char in the scanner
}

The findInLine() method searches through your scanner and returns the first String that matches the regular expression you give it.

回答4:

Console cons = System.console();

The above code line creates cons as a null reference. The code and output are given below:

Console cons = System.console();
if (cons != null) {
    System.out.println("Enter single character: ");
    char c = (char) cons.reader().read();
    System.out.println(c);
}else{
    System.out.println(cons);
}

Output :

null

The code was tested on macbook pro with java version "1.6.0_37"

回答5:

sc.next().charat(0).........is the method of entering character by user based on the number entered at the run time

example: sc.next().charat(2)------------>>>>>>>>

回答6:

Scanner sc = new Scanner (System.in)
char c = sc.next().trim().charAt(0);

来源：https://stackoverflow.com/questions/2597841/scanner-method-to-get-a-char