code: public HttpRequest form(Map<String, Object> formMap) {
  		if (MapUtil.isNotEmpty(formMap)) {
  			for (Map.Entry<String, Object> entry : formMap.entrySet()) {
  				form(entry.getKey(), entry.getValue());
  			}
  		}
  		return this;
  	}
docs: 设置map类型表单数据
  
  @param formMap 表单内容
  @return this