查找所有的变量

/**
*
* 查找所有的变量
*
* @param str
* @return String
*/
private String[] findVariable(String str) {
        StringBuffer temp = new StringBuffer("");
        int beginIndex = str.indexOf(FLAG_START);
        int endIndex = str.indexOf(FLAG_END);
        while(beginIndex != -1 && endIndex != -1) {
            temp.append(str.substring(beginIndex + 2, endIndex));
            str = str.substring(endIndex+1);
            beginIndex = str.indexOf(FLAG_START);
            endIndex = str.indexOf(FLAG_END);
            if(beginIndex != -1 && endIndex !=-1 ) {
                temp.append(",");
            }
        }
        if(!temp.toString().equals("")) {
            return temp.toString().split(",");
        }
        return null;
    }