private static <T> String fromBean(T obj) throws Exception {
        String json = "";
        log.debug(String.format("method start Object[obj:%s]", obj));
        if (obj != null) {   
            Class<?> cls = obj.getClass();
            Field[] fields = Reflect.getFields(cls);
            StringBuilder sb = new StringBuilder(fields.length * 20); //假设20是一个键值对的平均长度
            String name;
            Object value;
            for (Field field : fields) {
                name = field.getName();
                value = Reflect.getFieldValue(obj, field);
                sb.append('<').append(name).append('>')
                    .append(fromObject(value))
                    .append("</").append(name).append('>');
            }
            json = sb.toString();
        }
        log.debug(String.format("method stop return:String[%s]", json));
        return json;
    }