java生成不重复随机数

package cn.test;

import java.util.Random;

public class RandomTest {

/**产生不重复的随机数
* 方法一
* @param args
*/
public static String game(int count){
StringBuffer sb = new StringBuffer();
String str = "0123456789";
Random r = new Random();
for(int i=0;i<count;i++){
int num = r.nextInt(str.length());
sb.append(str.charAt(num));
str = str.replace((str.charAt(num)+""), "");
}
return sb.toString();
}
public static void main(String[] args) {
System.out.println(game(9));
}