refactor

src/main/java/com/alibaba/druid/hbase/jdbc/HBaseConnection.java

@@ -234,6 +234,10 @@ public class HBaseConnection extends ConnectionBase implements Connection {
         if (iface == Configuration.class) {
             return (T) engine.getConfig();
         }
+        
+        if (iface == HEngine.class) {
+            return (T) engine;
+        }
 
         if (iface == Connection.class || iface == HBaseConnection.class) {
             return (T) this;

src/main/java/com/alibaba/druid/hbase/jdbc/HPreparedStatement.java

@@ -1,6 +1,8 @@
 package com.alibaba.druid.hbase.jdbc;
 
+import java.sql.PreparedStatement;
 
-public interface HPreparedStatement extends HStatement {
+
+public interface HPreparedStatement extends PreparedStatement, HStatement {
 
 }

src/main/java/com/alibaba/druid/hbase/jdbc/HPreparedStatementImpl.java

@@ -1,6 +1,5 @@
 package com.alibaba.druid.hbase.jdbc;
 
-import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.sql.Types;
@@ -27,7 +26,7 @@ import com.alibaba.druid.sql.ast.statement.SQLSelectStatement;
 import com.alibaba.druid.sql.visitor.SQLEvalVisitor;
 import com.alibaba.druid.sql.visitor.SQLEvalVisitorUtils;
 
-public class HPreparedStatementImpl extends PreparedStatementBase implements PreparedStatement, HStatement {
+public class HPreparedStatementImpl extends PreparedStatementBase implements HPreparedStatement {
 
     private final String    sql;
     private String[]        columnNames;