修复警告

src/services/excel_service.rs

@@ -1,6 +1,3 @@
-use std::fs::File;
-use std::io::BufReader;
-
 use anyhow::Result;
 use calamine::{Data, DataType, open_workbook, Reader, Xlsx};
 
@@ -8,7 +5,6 @@ use crate::models::work_model::WorkModel;
 
 pub(crate) struct ExcelService {
     current_line: usize,
-    work_book: Xlsx<BufReader<File>>,
     sheet: calamine::Range<Data>,
 }
 
@@ -27,7 +23,6 @@ impl ExcelService {
         };
         let mut service = ExcelService {
             current_line: 0,
-            work_book,
             sheet,
         };
         service.current_line = service.find_first_useful_line();