newWorkbook() 수정

src/main/java/cokr/xit/base/docs/xls/XLS.java

@@ -40,6 +40,7 @@ public abstract class XLS extends AbstractComponent {
 	public <T extends XLS> T load(InputStream input) {
 		try {
 			workbook = newWorkbook(input);
+			sxssf = workbook instanceof SXSSFWorkbook;
 			return self();
 		} catch (Exception e) {
 			throw runtimeException(e);