public static String getKeyPairs(String key, Object value) {
        if (value != null) {
            return "&" + key + "=" + value.toString();
        } else {
            return "";
        }
    }
Gets key pairs.

@param key   the key
@param value the value
@return the key pairs
core/api/src/main/java/com/alipay/sofa/rpc/registry/utils/RegistryUtils.java