Random、随机颜色、UUID、全球唯一，随机字符串

package wzt;import java.awt.*;
import java.util.Random;
import java.util.UUID;public class Rand1 {public static void main(String[] args) {System.out.println(Math.PI);//Manth.random()返回0-1之间的随机小数System.out.println(Math.random());System.out.println(Math.random());System.out.println(Math.random());var rand=new Random();System.out.println(rand.nextBoolean());System.out.println(rand.nextBoolean());System.out.println(rand.nextBoolean());//0 1 2 随机整数System.out.println(rand.nextInt(3));//1-100的随机整数int num= rand.nextInt(100)+1;if (num<=30){System.out.println("恭喜你（"+num+"）中奖了");}else {System.out.println("很遗憾("+num+")没有中奖");}//随机颜色int rr=rand.nextInt(255);int gg= rand.nextInt(255);int bb= rand.nextInt(255);Color c=new Color(rr,gg,bb);//随机范围15-20for (int i=0; i<10; i++){int range= rand.nextInt(20-15+1)+15;System.out.println(range);}for (int i=0; i<5; i++){System.out.println(rand.nextDouble());}//全球唯一，随机字符串UUID u= UUID.randomUUID();System.out.println(u);//随机字符串System.out.println(u.toString().length());//随机字符串长度}
}