Improve error message for unsupported connection mode (sentinel)

Author: Veirisa

driver/src/main/java/jdbc/RedisConnection.java

@@ -44,10 +44,14 @@ public void checkMode() throws SQLException {
         }
         RedisMode clientMode = client.getMode();
         if (clientMode != serverMode) {
+            String clientModeName = toLowerCase(clientMode.name());
+            String serverModeName = toLowerCase(serverMode.name());
             String serverURLPrefix = RedisClientFactory.getURLPrefix(serverMode);
-            String urlFix = serverURLPrefix != null ? String.format("\nPlease change the URL prefix to \"%s\".", serverURLPrefix) : null;
-            throw new SQLException(String.format("The connection mode \"%s\" does not match the server mode \"%s\".%s",
-                    toLowerCase(clientMode.name()), toLowerCase(serverMode.name()), urlFix));
+            String messageTail = serverURLPrefix != null
+                    ? String.format("Please change the URL prefix to \"%s\".", serverURLPrefix)
+                    : String.format("Meanwhile, the connection mode \"%s\" is not supported at the moment.", serverModeName);
+            throw new SQLException(String.format("The connection mode \"%s\" does not match the server mode \"%s\".\n%s",
+                    clientModeName, serverModeName, messageTail));
         }
     }