diff --git a/src/main/java/com/alibaba/druid/pool/vendor/MSSQLValidConnectionChecker.java b/src/main/java/com/alibaba/druid/pool/vendor/MSSQLValidConnectionChecker.java
index 32b5ccbd0a..838d0696f3 100644
--- a/src/main/java/com/alibaba/druid/pool/vendor/MSSQLValidConnectionChecker.java
+++ b/src/main/java/com/alibaba/druid/pool/vendor/MSSQLValidConnectionChecker.java
@@ -1,66 +1,69 @@
-/*
- * Copyright 1999-2011 Alibaba Group Holding Ltd.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-package com.alibaba.druid.pool.vendor;
-
-import java.io.Serializable;
-import java.sql.Connection;
-import java.sql.SQLException;
-import java.sql.Statement;
-
-import com.alibaba.druid.pool.ValidConnectionChecker;
-import com.alibaba.druid.pool.ValidConnectionCheckerAdapter;
-import com.alibaba.druid.support.logging.Log;
-import com.alibaba.druid.support.logging.LogFactory;
-import com.alibaba.druid.util.JdbcUtils;
-
-/**
- * A MSSQLValidConnectionChecker.
- */
-public class MSSQLValidConnectionChecker extends ValidConnectionCheckerAdapter implements ValidConnectionChecker, Serializable {
-
-    private static final long   serialVersionUID = 1L;
-
-    private static final String QUERY            = "SELECT 1";
-    private static final Log    LOG              = LogFactory.getLog(MSSQLValidConnectionChecker.class);
-
-    public boolean isValidConnection(final Connection c, String valiateQuery, int validationQueryTimeout) {
-        try {
-            if (c.isClosed()) {
-                return false;
-            }
-        } catch (SQLException ex) {
-            // skip
-            return false;
-        }
-
-        Statement stmt = null;
-
-        try {
-            stmt = c.createStatement();
-            stmt.setQueryTimeout(validationQueryTimeout);
-            stmt.execute(QUERY);
-            return true;
-        } catch (SQLException e) {
-            if (LOG.isWarnEnabled()) {
-                LOG.warn("warning: connection validation failed for current managed connection.");
-            }
-            return false;
-        } finally {
-            JdbcUtils.close(stmt);
-        }
-    }
-
-}
+/*
+ * Copyright 1999-2011 Alibaba Group Holding Ltd.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.alibaba.druid.pool.vendor;
+
+import java.io.Serializable;
+import java.sql.Connection;
+import java.sql.SQLException;
+import java.sql.Statement;
+
+import com.alibaba.druid.pool.ValidConnectionChecker;
+import com.alibaba.druid.pool.ValidConnectionCheckerAdapter;
+import com.alibaba.druid.support.logging.Log;
+import com.alibaba.druid.support.logging.LogFactory;
+import com.alibaba.druid.util.JdbcUtils;
+
+/**
+ * A MSSQLValidConnectionChecker.
+ */
+public class MSSQLValidConnectionChecker extends ValidConnectionCheckerAdapter implements ValidConnectionChecker, Serializable {
+
+    private static final long serialVersionUID = 1L;
+
+    private static final Log  LOG              = LogFactory.getLog(MSSQLValidConnectionChecker.class);
+
+    public MSSQLValidConnectionChecker(){
+
+    }
+
+    public boolean isValidConnection(final Connection c, String valiateQuery, int validationQueryTimeout) {
+        try {
+            if (c.isClosed()) {
+                return false;
+            }
+        } catch (SQLException ex) {
+            // skip
+            return false;
+        }
+
+        Statement stmt = null;
+
+        try {
+            stmt = c.createStatement();
+            stmt.setQueryTimeout(validationQueryTimeout);
+            stmt.execute(valiateQuery);
+            return true;
+        } catch (SQLException e) {
+            if (LOG.isWarnEnabled()) {
+                LOG.warn("warning: connection validation failed for current managed connection.");
+            }
+            return false;
+        } finally {
+            JdbcUtils.close(stmt);
+        }
+    }
+
+}
diff --git a/src/test/java/com/alibaba/druid/bvt/pool/vendor/MSSQLValidConnectionCheckerTest.java b/src/test/java/com/alibaba/druid/bvt/pool/vendor/MSSQLValidConnectionCheckerTest.java
new file mode 100644
index 0000000000..4f6f525078
--- /dev/null
+++ b/src/test/java/com/alibaba/druid/bvt/pool/vendor/MSSQLValidConnectionCheckerTest.java
@@ -0,0 +1,40 @@
+package com.alibaba.druid.bvt.pool.vendor;
+
+import java.sql.SQLException;
+
+import junit.framework.TestCase;
+
+import org.junit.Assert;
+
+import com.alibaba.druid.mock.MockConnection;
+import com.alibaba.druid.pool.vendor.MSSQLValidConnectionChecker;
+
+public class MSSQLValidConnectionCheckerTest extends TestCase {
+
+    public void test_0() throws Exception {
+        MSSQLValidConnectionChecker checker = new MSSQLValidConnectionChecker();
+
+        MockConnection conn = new MockConnection();
+
+        Assert.assertTrue(checker.isValidConnection(conn, "select 1", 10));
+
+    }
+
+    public void test_closed() throws Exception {
+        MSSQLValidConnectionChecker checker = new MSSQLValidConnectionChecker();
+
+        MockConnection conn = new MockConnection();
+
+        conn.close();
+        Assert.assertFalse(checker.isValidConnection(conn, "select 1", 10));
+    }
+
+    public void test_error() throws Exception {
+        MSSQLValidConnectionChecker checker = new MSSQLValidConnectionChecker();
+
+        MockConnection conn = new MockConnection();
+        conn.setError(new SQLException());
+
+        Assert.assertFalse(checker.isValidConnection(conn, "select 1", 10));
+    }
+}