1.代码
package com.xtm.java.test; import java.util.Random; import java.util.concurrent.ThreadLocalRandom; public class Test{ public static void main(String args[]){ Random random = new Random(System.currentTimeMillis()); //生成0~19的随机数 int val1 = random.nextInt(20); ThreadLocalRandom threadLocalRandom = ThreadLocalRandom.current(); //生成4~20的随机数 int val2 = threadLocalRandom.nextInt(4, 20); System.out.println(val1+"-----"+val2); } }