產生90-100的重複的隨機數:
public class RandomTest { public static void main(String[] args){ /* * Math.random()方法默認double類型,所以需要強制轉換為int */ int x=(int)(Math.random()*(100-90+1)+90); //(max-min+1)+min=min-max System.out.println(x); } }產生90-100不重複的隨機數:
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; //隨機數個數Random random = new Random();Set<Integer> set=new HashSet<>(); //hashset容器中只能存儲不重複的對象while(set.size()<count){ //hashset儲存的元素數目int x = random.nextInt(max-min+1)+min; //產生隨機數set.add(x); //把隨機數添加到hashset容器中}for(int i:set){ //foreach遍歷容器元素System.out.println(i);}}}每一秒產生90-100的重複的隨機數:
import java.util.Random;import java.util.Timer;import java.util.TimerTask;public class RandomTest { void timer(){Timer timer = new Timer(); //創建定時對象timer.schedule(new TimerTask() {public void run() { //TimerTask實現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(); //調用定時任務} }本文轉載於:https://www.idaobin.com/archives/301.html