[Java]生成32位随机字符ID

/**
	 * 生成32位编码
	 * @return string
	 */
	public static String getUUID(){
		String uuid = UUID.randomUUID().toString().trim().replaceAll("-", "");
		return uuid;
	}
	
	/**
	 * 自定义规则生成32位编码
	 * @return string
	 */
	public static String getUUIDByRules(String rules)
    {

	String radStr = rules;
	int rpoint = 0;
        StringBuffer generateRandStr = new StringBuffer();
        Random rand = new Random();
        int length = 32;
        for(int i=0;i<length;i++)
        {
        	if(rules!=null){
        		rpoint = rules.length();
        		int randNum = rand.nextInt(rpoint);
        		generateRandStr.append(radStr.substring(randNum,randNum+1));
        	}
        }
        return generateRandStr+"";
    }