详解如何使用SpringBoot封装Excel生成器

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.2</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>4.1.2</version>
</dependency>

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;
public class ExcelGenerator {
    private Workbook workbook;
    private Sheet sheet;
    public ExcelGenerator() {
        // 创建Workbook和Sheet对象
        workbook = new XSSFWorkbook();
        sheet = workbook.createSheet("Sheet1");
    }
    public void setColumnNames(List<String> columnNames) {
        // 设置列名
        Row row = sheet.createRow(0);
        for (int i = 0; i < columnNames.size(); i++) {
            Cell cell = row.createCell(i);
            cell.setCellValue(columnNames.get(i));
        }
    }
    public void setData(List<List<Object>> data) {
        // 填充数据
        for (int i = 0; i < data.size(); i++) {
            Row row = sheet.createRow(i + 1);
            List<Object> rowData = data.get(i);
            for (int j = 0; j < rowData.size(); j++) {
                Cell cell = row.createCell(j);
                Object value = rowData.get(j);
                if (value instanceof String) {
                    cell.setCellValue((String) value);
                } else if (value instanceof Integer) {
                    cell.setCellValue((Integer) value);
                } else if (value instanceof Double) {
                    cell.setCellValue((Double) value);
                }
                // 添加更多类型的判断和处理
            }
        }
    }
    public void setCellStyle(CellStyle style) {
        // 设置单元格样式
        for (Row row : sheet) {
            for (Cell cell : row) {
                cell.setCellStyle(style);
            }
        }
    }
    public void export(String filePath) throws IOException {
        // 导出Excel文件
        try (FileOutputStream fos = new FileOutputStream(filePath)) {
            workbook.write(fos);
        }
    }
}

public class ExcelExample {
    public static void main(String[] args) {
        List<String> columnNames = Arrays.asList("Name", "Age", "Email");
        List<List<Object>> data = Arrays.asList(
                Arrays.asList("John Doe", 25, "john.doe@example.com"),
                Arrays.asList("Jane Smith", 30, "jane.smith@example.com"),
                Arrays.asList("Tom Lee", 35, "tom.lee@example.com")
        );
        ExcelGenerator excelGenerator = new ExcelGenerator();
        excelGenerator.setColumnNames(columnNames);
        excelGenerator.setData(data);
        try {
            excelGenerator.export("output.xlsx");
            System.out.println("Excel file generated successfully.");
        } catch (IOException e) {
            System.err.println("Failed to generate Excel file: " + e.getMessage());
        }
    }
}