Java代码实现 Excel上传并保存数据库 根据Excel表中的教室名称获取到另一个表中的教室Id

以下是Java代码实现Excel上传并保存数据库，并根据教室名称获取教室ID的示例：

//导入所需的包
import java.io.File;
import java.io.IOException;
import java.util.Iterator;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;

@Controller
public class ExcelController {

   @Autowired
   private RoomDao roomDao; //自动注入RoomDao

   @RequestMapping(value = "/uploadExcel", method = RequestMethod.POST)
   public String uploadExcel(@RequestParam("file") MultipartFile file) throws IOException {

       //读取Excel文件
       HSSFWorkbook workbook = new HSSFWorkbook(file.getInputStream());
       HSSFSheet sheet = workbook.getSheetAt(0);

       Iterator<Row> rows = sheet.iterator();
       while (rows.hasNext()) {
           HSSFRow row = (HSSFRow) rows.next();
           Iterator<Cell> cells = row.cellIterator();

           String classroomName = null;
           while (cells.hasNext()) {
               HSSFCell cell = (HSSFCell) cells.next();
               int columnIndex = cell.getColumnIndex();

               switch (columnIndex) {
                   case 0:
                       classroomName = cell.getStringCellValue();
                       break;
                   //其他列的处理
               }
           }

           //根据教室名称获取教室ID
           Room room = roomDao.findByClassroomName(classroomName);
           if (room != null) {
               //将Excel中的数据保存到数据库中
               //...
           }
       }

       return "success"; //上传成功后跳转到成功页面
   }
}

需要注意的是，上述代码中的`RoomDao`是一个用于访问数据库的DAO类，需要根据具体的情况进行调整。同时，代码中的`findByClassroomName`方法是一个自定义的查询方法，需要在`RoomDao`中进行定义和实现。