add example.

Author: youngsofun

config/checkstyle/checkstyle.xml

@@ -12,7 +12,7 @@
             <property name="format" value="System\.(out|err)\.print(ln)?"/>
             <property name="message" value="Use logging framework instead of System.out.println"/>
             <property name="illegalPattern" value="true"/>
-            <property name="files" value="^(?!databend-jdbc/com/databend/jdbc/examples/).*\.java$"/>
+            <property name="files" value="^(?!databend-jdbc/src/main/java/com/databend/jdbc/examples/).*\.java$"/>
         </module>
 
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