import java.util.Random;
import java.util.UUID;
import java.util.concurrent.ThreadLocalRandom;

public class RandomDemo {

    public static void main(String[] args) {
        
        testRandomCode();
        testThreadLocalRandom();
        testUUID();
    }

    private static void testRandomCode() {
        // TODO Auto-generated method stub
        Random r1 = new Random(10);
        System.out.println(r1.nextBoolean());
        System.out.println(r1.nextInt());
        System.out.println(r1.nextInt(100));//表示0到100之间的随机数,包括0不包括100,前闭后开
        System.out.println(r1.nextDouble());
        System.out.println("------------");
        Random r2 = new Random(10);
        System.out.println(r2.nextBoolean());
        System.out.println(r2.nextInt());
        System.out.println(r2.nextInt(100));//表示0到100之间的随机数,包括0不包括100,前闭后开
        System.out.println(r2.nextDouble());
        System.out.println("------------");
        /*
         * Random类用于生产一个伪随机数(通过相同的种子,产生的随机数是相同的)
         * public Random():使用默认的种子,(以当前系统时间作为种子)
         * public Random(long seed):根据指定的种子.生产一个伪随机数
         * */
    }

    private static void testThreadLocalRandom() {
        // TODO Auto-generated method stub
        
        ThreadLocalRandom threadRandom = ThreadLocalRandom.current();
        System.out.println(threadRandom.nextInt(40, 99));//[50,99)之间 的数
        System.out.println("------------");
        
    }

    private static void testUUID() {
        // TODO Auto-generated method stub
        String uuid = UUID.randomUUID().toString();
        System.out.println(uuid);
        String uuid1 = UUID.randomUUID().toString();
        System.out.println(uuid1);
        
        
    }

}