fix bug

dbsyncer-connector/src/main/java/org/dbsyncer/connector/util/DatabaseUtil.java

@@ -1,5 +1,6 @@
 package org.dbsyncer.connector.util;
 
+import org.dbsyncer.common.util.StringUtil;
 import org.dbsyncer.connector.ConnectorException;
 
 import java.sql.Connection;
@@ -12,10 +13,12 @@ public abstract class DatabaseUtil {
     }
 
     public static Connection getConnection(String driverClassName, String url, String username, String password) throws SQLException {
-        try {
-            Class.forName(driverClassName);
-        } catch (ClassNotFoundException e) {
-            throw new ConnectorException(e.getCause());
+        if (StringUtil.isNotBlank(driverClassName)) {
+            try {
+                Class.forName(driverClassName);
+            } catch (ClassNotFoundException e) {
+                throw new ConnectorException(e.getCause());
+            }
         }
         return DriverManager.getConnection(url, username, password);
     }