java产生4位随机数

 /**
     * 产生4位随机数(0000-9999)
     * @return 4位随机数
     */
    public static String getFourRandom(){
        Random random = new Random();
        String fourRandom = random.nextInt(10000) + "";
        int randLength = fourRandom.length();
        if(randLength<4){
          for(int i=1; i<=4-randLength; i++)
              fourRandom = "0" + fourRandom  ;
      }
        return fourRandom;
    }