update checkstyle rule for Headers

src/resources/copyright.txt

+/*
+ * Copyright 1999-2015 dangdang.com.
+ * <p>
+ * 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.
+ * </p>
+ */

src/resources/sharding_checks.xml

@@ -7,6 +7,12 @@
     <module name="FileTabCharacter">
         <property name="eachLine" value="true"/>
     </module>
+    
+    <!-- Headers -->
+    <module name="Header">
+        <property name="headerFile" value="copyright.txt"/>
+        <property name="fileExtensions" value="java"/>
+    </module>
     <module name="TreeWalker">
         
         <!-- Naming Conventions -->