Random:
生成随机数
import java.util.Random; public class Demo { public static void main(String[] args){ Random r = new Random(); System.out.print(r.nextInt(50)); } }
Scanner:
键盘输入
//类似 python 中的 input import java.util.Scanner;; public class Demo { public static void main(String[] args) { Scanner input = new Scanner(System.in); System.out.println("输入一个整数") int x = input.nextInt(); //input.next() 输入一个字符串 System.out.println(x); //0 } }