[hotfix][column]Fix the issue of timestampColumn convert to long error (#1260)

Author: Paddy0523

chunjun-core/src/main/java/com/dtstack/chunjun/element/column/TimestampColumn.java

@@ -20,8 +20,6 @@
 import com.dtstack.chunjun.element.AbstractBaseColumn;
 import com.dtstack.chunjun.throwable.CastException;
 
-import org.apache.commons.net.ntp.TimeStamp;
-
 import java.math.BigDecimal;
 import java.sql.Time;
 import java.sql.Timestamp;
@@ -140,15 +138,15 @@ public BigDecimal asBigDecimal() {
         if (null == data) {
             return null;
         }
-        return new BigDecimal(((TimeStamp) data).getTime());
+        return new BigDecimal(((Timestamp) data).getTime());
     }
 
     @Override
     public Long asLong() {
         if (null == data) {
             return null;
         }
-        return ((TimeStamp) data).getTime();
+        return ((Timestamp) data).getTime();
     }
 
     @Override