Random rand = new Random(47); 
System.out.println(rand.nextInt()); 

double d = Math.random(); 

Random rand = new Random(); 
System.out.println(rand.nextInt()); 

//方式一 
Random rand = new Random();
for (int i = 0; i < 4; i++){
	System.out.print(Math.abs(rand.nextint() % 10));
}
//以上通過(guò)rand.next產(chǎn)生隨機(jī)數(shù)，因可能存在負(fù)數(shù)，用Math.abs取絕對(duì)值，然后取模10，產(chǎn)生的結(jié)果在10以內(nèi) 
//方式二 
Random rand = new Random();
for (int i = 0; i < 4; i++){
	System.out.print(rand2.nextint(10));
}
//以上使用api直接產(chǎn)生10以內(nèi)的隨機(jī)數(shù)

import java.awt.Color;
import java.util.Collection;
import java.util.Iterator;
import java.util.Random;
public class RandomSet 
{
	static Random random = new Random();
	//獲得一個(gè)給定范圍的隨機(jī)整數(shù) 
	public static int getRandomNum(int smallistNum,int BiggestNum) 
	 {
		return (Math.abs(random.nextint())%(BiggestNum-smallistNum+1))+smallistNum;
	}
	//獲得一個(gè)隨機(jī)的布爾值 
	public static Boolean getRandomBoolean() 
	 {
		return (getRandomNum(0,1) == 1);
	}
	//獲得一個(gè)隨機(jī)在0~1的浮點(diǎn)數(shù) 
	public static float getRandomFloatIn_1() 
	 {
		return (float)getRandomNum(0,1000)/1000;
	}
	//獲得一個(gè)隨機(jī)的顏色 
	public static Color getRandomColor() 
	 {
		float R = (float)getRandomNum(0,255)/255;
		float G = (float)getRandomNum(0,255)/255;
		float B = (float)getRandomNum(0,255)/255;
		return new Color(R,G,B);
	}
	//以一定概率返回一個(gè)布爾值 
	public static Boolean getRate(int rate) 
	 {
		if(rate<0 || rate > 100) 
		  {
			return false;
		} else 
		  {
			if(getRandomNum(0,100)<rate) 
			   {
				return true;
			} else 
			   {
				return false;
			}
		}
	}
	//返回給定數(shù)組中的一個(gè)隨機(jī)元素 
	public static <T> T getElement(T[] t) 
	 {
		int index = getRandomNum(0,t.length - 1);
		return t[index];
	}
	//返回給定Collection中的一個(gè)隨機(jī)元素 
	public static <T> T getElement(Collection<? extends T> c) 
	 {
		int atmp = getRandomNum(0,c.size() - 1);
		Iterator<? extends T> iter = c.iterator();
		while(atmp > 0) 
		  {
			atmp--;
			iter.next();
		}
		return iter.next();
	}
}