[#367][BugFix]enhance unqualified load-url config validate and test

Author: xumanbu

src/main/java/com/starrocks/connector/flink/table/sink/StarRocksSinkOptions.java

@@ -380,7 +380,7 @@ public boolean isUseUnifiedSinkApi() {
     private void validateStreamLoadUrl() {
         tableOptions.getOptional(LOAD_URL).ifPresent(urlList -> {
             for (String host : urlList) {
-                if (host.split(":").length < 2) {
+                if (host.split(":").length != 2) {
                     throw new ValidationException(String.format(
                             "Could not parse host '%s' in option '%s'. It should follow the format 'host_name:port'.",
                             host,

starrocks-stream-load-sdk/src/main/java/com/starrocks/data/load/stream/DefaultStreamLoader.java

@@ -45,6 +45,7 @@
 
 import java.io.Serializable;
 import java.net.HttpURLConnection;
+import java.net.MalformedURLException;
 import java.net.URL;
 import java.util.Collections;
 import java.util.HashMap;
@@ -388,6 +389,8 @@ private boolean testHttpConnection(String host) {
             connection.connect();
             connection.disconnect();
             return true;
+        } catch (MalformedURLException e) {
+            throw new IllegalArgumentException("Illegal stream load url config, please check config value.", e);
         } catch (Exception e) {
             log.warn("Failed to connect to address:{}", host, e);
             return false;