public class RandomTest { 
 public static void main(String[] args){
 	/*
 	 * Math.random()方法默認(rèn)double類型，所以需要強(qiáng)制轉(zhuǎn)換為int
 	 */
 int x=(int)(Math.random()*(100-90+1)+90); //(max-min+1)+min=min-max
 System.out.println(x); 
 } 
}

import java.util.HashSet;
import java.util.Random;
import java.util.Set;

public class RandomTest {
	public static void main(String args[]){
		int max=100; //最大值
		int min=90; //最小值
		int count=max-min; //隨機(jī)數(shù)個(gè)數(shù)
		Random random = new Random();
		Set<Integer> set=new HashSet<>(); //hashset容器中只能存儲(chǔ)不重復(fù)的對(duì)象
		while(set.size()<count){ //hashset儲(chǔ)存的元素?cái)?shù)目
			 int x = random.nextInt(max-min+1)+min; //產(chǎn)生隨機(jī)數(shù)
			 set.add(x); //把隨機(jī)數(shù)添加到hashset容器中
		}
		for(int i:set){ //foreach遍歷容器元素
			System.out.println(i);
		}
	}
}

import java.util.Random;
import java.util.Timer;
import java.util.TimerTask;

public class RandomTest {
	 void timer(){
		Timer timer = new Timer(); //創(chuàng)建定時(shí)對(duì)象
		timer.schedule(new TimerTask() {
			public void run() { //TimerTask實(shí)現(xiàn) Runnable接口的run方法
				 Random random = new Random();
				 int x = random.nextInt(100-90+1)+90; //(max-min+1)+min=min至max
//				 int x=random.nextInt(100)%(100-90+1) + 90; //同樣的效果
				 System.out.println(x);
			}
			
		},0,1000); //0表示無延遲，1000ms=1s
	}
 public static void main(String[] args){
 	RandomTest ran=new RandomTest();
 	ran.timer(); //調(diào)用定時(shí)任務(wù)
 } 
}