Java Scanner用法及代码示例

// Java program to read data of various types 
// using Scanner class.
import java.util.Scanner;
// Driver Class
public class ScannerDemo1 {
      // main function
    public static void main(String[] args)
    {
        // Declare the object and initialize with
        // predefined standard input object
        Scanner sc = new Scanner(System.in);
        // String input
        String name = sc.nextLine();
        // Character input
        char gender = sc.next().charAt(0);
        // Numerical data input
        // byte, short and float can be read
        // using similar-named functions.
        int age = sc.nextInt();
        long mobileNo = sc.nextLong();
        double cgpa = sc.nextDouble();
        // Print the values to check if the input was
        // correctly obtained.
        System.out.println("Name: " + name);
        System.out.println("Gender: " + gender);
        System.out.println("Age: " + age);
        System.out.println("Mobile Number: " + mobileNo);
        System.out.println("CGPA: " + cgpa);
    }
}

// Java program to read some values using Scanner
// class and print their mean.
import java.util.Scanner;
public class ScannerDemo2 {
    public static void main(String[] args)
    {
        // Declare an object and initialize with
        // predefined standard input object
        Scanner sc = new Scanner(System.in);
        // Initialize sum and count of input elements
        int sum = 0, count = 0;
        // Check if an int value is available
        while (sc.hasNextInt()) {
            // Read an int value
            int num = sc.nextInt();
            sum += num;
            count++;
        }
        if (count > 0) {
            int mean = sum / count;
            System.out.println("Mean: " + mean);
        }
        else {
            System.out.println(
                "No integers were input. Mean cannot be calculated.");
        }
    }
}