java生成4位随机数工具类代码，可用于发送验证码

import java.util.Random;

public class GetRandom {
    public static String getFourRandom(){
        Random random = new Random();
        String fourRandom = random.nextInt(10000) + "";
        int randLength = fourRandom.length();
        if(randLength<4){
            for(int i=1; i<=4-randLength; i++)
                fourRandom = "0" + fourRandom ;
        }
        return fourRandom;
    }
}