学生管理系统学生数据的导入导出,Java代码

以下是一个简单的Java代码示例，演示如何使用Apache POI库将学生数据导入和导出到Excel文件中。

导入数据：

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class StudentDataImporter {

    public List<Student> importData(File file) throws IOException {
        List<Student> students = new ArrayList<>();

        FileInputStream inputStream = new FileInputStream(file);
        Workbook workbook = new XSSFWorkbook(inputStream);
        Sheet sheet = workbook.getSheetAt(0);

        Iterator<Row> iterator = sheet.iterator();
        while (iterator.hasNext()) {
            Row currentRow = iterator.next();
            if (currentRow.getRowNum() == 0) {
                continue; // Skip header row
            }

            Iterator<Cell> cellIterator = currentRow.iterator();
            Student student = new Student();
            while (cellIterator.hasNext()) {
                Cell currentCell = cellIterator.next();
                int columnIndex = currentCell.getColumnIndex();
                switch (columnIndex) {
                    case 0:
                        student.setId((int) currentCell.getNumericCellValue());
                        break;
                    case 1:
                        student.setName(currentCell.getStringCellValue());
                        break;
                    case 2:
                        student.setAge((int) currentCell.getNumericCellValue());
                        break;
                    case 3:
                        student.setGrade(currentCell.getStringCellValue());
                        break;
                    default:
                        // Ignore extra columns
                }
            }
            students.add(student);
        }

        workbook.close();
        inputStream.close();

        return students;
    }

}

导出数据：

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class StudentDataExporter {

    public void exportData(List<Student> students, File file) throws IOException {
        Workbook workbook = new XSSFWorkbook();
        Sheet sheet = workbook.createSheet("Students");

        // Create header row
        Row headerRow = sheet.createRow(0);
        Cell idHeader = headerRow.createCell(0);
        idHeader.setCellValue("ID");
        Cell nameHeader = headerRow.createCell(1);
        nameHeader.setCellValue("Name");
        Cell ageHeader = headerRow.createCell(2);
        ageHeader.setCellValue("Age");
        Cell gradeHeader = headerRow.createCell(3);
        gradeHeader.setCellValue("Grade");

        // Create data rows
        int rowIndex = 1;
        for (Student student : students) {
            Row currentRow = sheet.createRow(rowIndex++);
            Cell idCell = currentRow.createCell(0);
            idCell.setCellValue(student.getId());
            Cell nameCell = currentRow.createCell(1);
            nameCell.setCellValue(student.getName());
            Cell ageCell = currentRow.createCell(2);
            ageCell.setCellValue(student.getAge());
            Cell gradeCell = currentRow.createCell(3);
            gradeCell.setCellValue(student.getGrade());
        }

        FileOutputStream outputStream = new FileOutputStream(file);
        workbook.write(outputStream);
        workbook.close();
        outputStream.close();
    }

}

请注意，这只是一个示例，您需要根据自己的需求进行修改。