正如@shmosel提到的，我也觉得你的问题出在文件阅读器上。检查下面的代码是否比你现在的代码运行得更快。
试试下面的代码：

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import java.io.FileInputStream;
import java.io.IOException;
public class ExcelReader {
    public static void main(String[] args) {
        try (FileInputStream file = new FileInputStream("path/to/your/excel/file.xlsx")) {
            
            Workbook workbook = new XSSFWorkbook(file);
            
            Sheet sheet = workbook.getSheetAt(0);
            
            for (Row row : sheet) {
                // Iterate over cells
                for (Cell cell : row) {
                    
                    System.out.print(cell.toString() + "\t");
                }
                
                System.out.println();
            }
            
            workbook.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

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org.ttzero:eec:0.5.12支持阅读数百万行Excel github links，遗憾的是，只有中文文档可用

try (ExcelReader reader = ExcelReader.read(Paths.get("./abc.xlsx"))) {
    // Print
    reader.sheet(0).rows().forEach(System.out::println);
    // Convert to Java Bean
    List<Item> list =  reader.sheet(0)
        .header(1)  // <- Specify the title line number
        .rows()
        .map(row -> row.to(Item.class)) // <- Convert to Java Bean
        .collect(Collectors.toList());
}

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