您需要一些东西像扫描仪一样从控制台读取值。
代码应如下所示：

You need something like a scanner to read-in values from console. The code should look like that:

import java.util.Scanner;

class TUI {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter the two numbers:");
        System.out.println("Enter n1:");
        int n1 = scanner.nextInt();
        System.out.println("Enter n2:");
        int n2 = scanner.nextInt();
        int total = n1 + n2;
        System.out.println("Total is =" + total + ".");
        scanner.close();
    }
}

我希望它会有所帮助。