import java.util.Random;

/**
 * @ClassName RandomUtils
 * @Description: 随机数工具类
 * @Author yuejiang.huang
 * @Date 2020/7/9 10:54
 **/
public class RandomUtils {

    /**
     * 随机生成 X位数 的 数字字符串
     *
     * @param x
     * @return
     */
    public static String randomNumberString(Integer x){
        String result = "";
        int num = 0;
        Random random = new Random();
        for (int i = 0; i < x; i++){
            num = random.nextInt(10);
            result = result + String.valueOf(num);
        }
        return result;
    }

    public static void main(String[] args) {
        for (int i = 0; i < 10; i++){
            System.out.print(RandomUtils.randomNumberString(4)+"\r\n");
        }

    }

}