public String getParam(String key, String defaultValue) {
        if (params != null) {
            String value = params.get(key);
            if (StringUtils.isEmpty(value)) {
                return defaultValue;
            }
            return value;
        }
        return null;
    }
@author Robert HG (254963746@qq.com) on 10/26/15.
lts-core/src/main/java/com/github/ltsopensource/cmd/HttpCmdRequest.java