java导出excel案例

以下是一个简单的Java导出Excel的示例：

1. 首先，需要添加poi和poi-ooxml依赖：

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>3.17</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.17</version>
</dependency>

2. 创建一个工具类来导出Excel：

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.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class ExcelUtil {
    public static void export(List<Object[]> data, String fileName) throws IOException {
        XSSFWorkbook workbook = new XSSFWorkbook();
        XSSFSheet sheet = workbook.createSheet("Sheet1");

        // 设置表头
        XSSFRow headerRow = sheet.createRow(0);
        String[] headers = {"Name", "Age", "Gender"};
        for (int i = 0; i < headers.length; i++) {
            XSSFCell cell = headerRow.createCell(i);
            cell.setCellValue(headers[i]);
        }

        // 填充数据
        int rowNum = 1;
        for (Object[] row : data) {
            XSSFRow dataRow = sheet.createRow(rowNum++);
            for (int i = 0; i < row.length; i++) {
                XSSFCell cell = dataRow.createCell(i);
                cell.setCellValue(row[i].toString());
            }
        }

        // 格式化单元格
        XSSFCellStyle cellStyle = workbook.createCellStyle();
        cellStyle.setWrapText(true);
        for (int i = 0; i < headers.length; i++) {
            sheet.autoSizeColumn(i);
            sheet.setColumnWidth(i, sheet.getColumnWidth(i) + 500);
            for (Row row : sheet) {
                Cell cell = row.getCell(i);
                if (cell != null) {
                    cell.setCellStyle(cellStyle);
                }
            }
        }

        // 导出Excel
        FileOutputStream outputStream = new FileOutputStream(fileName);
        workbook.write(outputStream);
        outputStream.close();
    }
}

3. 在主函数中调用导出方法：

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] args) throws IOException {
        // 准备数据
        List<Object[]> data = new ArrayList<>();
        data.add(new Object[]{"Tom", 20, "Male"});
        data.add(new Object[]{"Lily", 22, "Female"});
        data.add(new Object[]{"Lucy", 21, "Female"});

        // 导出Excel
        ExcelUtil.export(data, "output.xlsx");
    }
}

以上示例演示了如何使用Java导出Excel文件。实际上，Excel导出的实现方式还有很多，可以根据具体需求选择合适的方法。