fix

fine-druid/src/com/fr/third/alibaba/druid/pool/vendor/MSSQLValidConnectionChecker.java

@@ -36,10 +36,15 @@ public class MSSQLValidConnectionChecker extends ValidConnectionCheckerAdapter i
     }
     
     public boolean isValidConnection(final Connection c, String validateQuery, int validationQueryTimeout) throws Exception {
+        
         if (c.isClosed()) {
             return false;
         }
         
+        if (validateQuery == null || validateQuery.isEmpty()) {
+            validateQuery = "select 1";
+        }
+        
         Statement stmt = null;
         
         try {