java:控制台输入方法

1 最简单的Scanner方法

public class Main {
    public static void main(String[] args){
    Scanner a=new Scanner(System.in);
        int aNum=Integer.parseInt(a.nextLine());
        Scanner b=new Scanner(System.in);
        int bNum=Integer.parseInt(b.nextLine());
        System.out.println(aNum+bNum);
    }
}

2 使用BufferedReader方法

public class Main {
    public static void main(String[] args) throws Exception{
        InputStreamReader isr = new InputStreamReader(System.in);
        BufferedReader br = new BufferedReader(isr);
        System.out.println("请输入第一个数");
        String a1 = br.readLine();
        System.out.println("请输入第二个数");
        String a2 = br.readLine();
        System.out.println(Float.parseFloat(a1)+Float.parseFloat(a2));
   }
}

3 使用try和BufferedReader方法

public class Main {
    public static void main(String[] args) {
        try {
            InputStreamReader isr = new InputStreamReader(System.in);
            BufferedReader br = new BufferedReader(isr);

            System.out.println("请输入第一个数");
            String a1 = br.readLine();
            System.out.println("请输入第二个数");
            String a2 = br.readLine();

            float num1 = Float.parseFloat(a1);
            float num2 = Float.parseFloat(a2);

            System.out.println(num1+num2);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}