SpringBoot使用Apache POI实现导入导出Excel文件

<dependencies>
    <!-- Spring Boot Starter Web -->
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-web</artifactId>
    </dependency>

    <!-- Apache POI 依赖 -->
    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi-ooxml</artifactId>
        <version>5.2.3</version>
    </dependency>

    <!-- Lombok (可选，用于简化代码) -->
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <optional>true</optional>
    </dependency>

    <!-- 其他依赖 -->
</dependencies>

package com.example.exceldemo;

import lombok.Data;

@Data
public class UserData {

    private Integer id;

    private String name;

    private Integer age;

    private String email;
}

package com.example.exceldemo;

import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import org.springframework.http.HttpHeaders;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.bind.annotation.*;
import org.springframework.web.multipart.MultipartFile;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

@RestController
public class ExcelController {

    @GetMapping("/export")
    public ResponseEntity<byte[]> exportExcel() {
        String fileName = "用户数据.xlsx";
        List<UserData> userList = generateUserData();

        byte[] bytes = exportToExcel(userList);

        HttpHeaders headers = new HttpHeaders();
        headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
        headers.setContentDispositionFormData("attachment", fileName);

        return ResponseEntity.ok()
                .headers(headers)
                .body(bytes);
    }

    private List<UserData> generateUserData() {
        List<UserData> list = new ArrayList<>();
        for (int i = 1; i <= 100; i++) {
            UserData user = new UserData();
            user.setId(i);
            user.setName("用户" + i);
            user.setAge(20 + i % 30);
            user.setEmail("user" + i + "@example.com");
            list.add(user);
        }
        return list;
    }

    private byte[] exportToExcel(List<UserData> userList) {
        Workbook workbook = new XSSFWorkbook();
        Sheet sheet = workbook.createSheet("用户数据");

        // 创建表头
        Row header = sheet.createRow(0);
        header.createCell(0).setCellValue("编号");
        header.createCell(1).setCellValue("姓名");
        header.createCell(2).setCellValue("年龄");
        header.createCell(3).setCellValue("邮箱");

        // 写入数据
        for (int i = 0; i < userList.size(); i++) {
            Row row = sheet.createRow(i + 1);
            UserData user = userList.get(i);
            row.createCell(0).setCellValue(user.getId());
            row.createCell(1).setCellValue(user.getName());
            row.createCell(2).setCellValue(user.getAge());
            row.createCell(3).setCellValue(user.getEmail());
        }

        // 写入到字节数组
        ByteArrayOutputStream out = new ByteArrayOutputStream();
        try {
            workbook.write(out);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                workbook.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

        return out.toByteArray();
    }

    @PostMapping("/import")
    public String importExcel(@RequestParam("file") MultipartFile file) {
        try (InputStream inputStream = file.getInputStream()) {
            List<UserData> userList = new ArrayList<>();
            Workbook workbook = new XSSFWorkbook(inputStream);
            Sheet sheet = workbook.getSheetAt(0);
            Iterator<Row> iterator = sheet.iterator();

            // 跳过表头
            if (iterator.hasNext()) {
                iterator.next();
            }

            while (iterator.hasNext()) {
                Row row = iterator.next();
                UserData user = new UserData();
                user.setId((int) row.getCell(0).getNumericCellValue());
                user.setName(row.getCell(1).getStringCellValue());
                user.setAge((int) row.getCell(2).getNumericCellValue());
                user.setEmail(row.getCell(3).getStringCellValue());
                userList.add(user);
            }

            // 处理导入的数据，例如保存到数据库
            processUserData(userList);

            return "导入成功，共导入 " + userList.size() + " 条数据";
        } catch (IOException e) {
            e.printStackTrace();
            return "导入失败: " + e.getMessage();
        }
    }

    private void processUserData(List<UserData> userList) {
        // 这里可以添加将数据保存到数据库的逻辑
        // 例如使用 JPA 或 MyBatis 等持久层框架
        userList.forEach(user -> {
            // 模拟保存操作
            System.out.println("保存用户: " + user);
        });
    }
}

<!DOCTYPE html>
<html>
<head>
    <title>Excel 导入</title>
</head>
<body>
    <h1>导入 Excel 文件</h1>
    <form method="POST" enctype="multipart/form-data" action="/import">
        <input type="file" name="file" accept=".xlsx, .xls" />
        <button type="submit">上传</button>
    </form>
</body>
</html>