package com.springboot.ssm.util;

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.support.ExcelTypeEnum;
import lombok.extern.slf4j.Slf4j;
import org.apache.poi.util.IOUtils;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
import java.util.List;

/**
 * Excel工具类
 */
@Slf4j
public class ExcelUtils {

    /**
     * 导出Excel(07版.xlsx)到指定路径下
     *
     * @param path      路径
     * @param excelName Excel名称
     * @param sheetName sheet页名称
     * @param clazz     Excel要转换的类型
     * @param data      要导出的数据
     */
    public static void export2File(String path, String excelName, String sheetName, Class clazz, List data) {
        String fileName = path.concat(excelName).concat(ExcelTypeEnum.XLSX.getValue());
        EasyExcel.write(fileName, clazz).sheet(sheetName).doWrite(data);
    }

    /**
     * 导出Excel(07版.xlsx)到web
     *
     * @param response  响应
     * @param excelName Excel名称
     * @param sheetName sheet页名称
     * @param clazz     Excel要转换的类型
     * @param data      要导出的数据
     * @throws Exception
     */
    public static void export2Web(HttpServletResponse response, String excelName, String sheetName, Class clazz, List data) throws Exception {
        response.setContentType("application/vnd.ms-excel");
        response.setCharacterEncoding("utf-8");
        // 这里URLEncoder.encode可以防止中文乱码
        excelName = URLEncoder.encode(excelName, "UTF-8");
        response.setHeader("Content-disposition", "attachment;filename=" + excelName + ExcelTypeEnum.XLSX.getValue());
        EasyExcel.write(response.getOutputStream(), clazz).sheet(sheetName).doWrite(data);
    }

    /**
     * 将指定位置指定名称的Excel导出到web
     *
     * @param response  响应
     * @param path      文件路径
     * @param excelName 文件名称
     * @return
     * @throws UnsupportedEncodingException
     */
    public static String export2Web4File(HttpServletResponse response, String path, String excelName) throws UnsupportedEncodingException {
        File file = new File(path.concat(excelName).concat(ExcelTypeEnum.XLSX.getValue()));
        if (!file.exists()) {
            return "文件不存在！";
        }

        response.setContentType("application/vnd.ms-excel");
        response.setCharacterEncoding("utf-8");
        // 这里URLEncoder.encode可以防止中文乱码
        excelName = URLEncoder.encode(excelName, "UTF-8");
        response.setHeader("Content-disposition", "attachment;filename=" + excelName + ExcelTypeEnum.XLSX.getValue());

        try (
                FileInputStream in = new FileInputStream(file);
                ServletOutputStream out = response.getOutputStream();
        ) {
            IOUtils.copy(in, out);
            return "导出成功！";
        } catch (Exception e) {
            log.error("导出文件异常：", e);
        }

        return "导出失败！";
    }

}

// easyexcel导出Excel到指定位置
@GetMapping("/export2File")
@ResponseBody
public String export2File() {
    ExcelUtils.export2File(path, "用户表", "用户信息", User.class, userService.getAll());
    return "导出成功";
}

// easyexcel导出Excel到web
@GetMapping("/export2Web")
public void export2Web(HttpServletResponse response) {
    try {
        ExcelUtils.export2Web(response, "用户表", "用户信息", User.class, userService.getAll());
    } catch (Exception e) {
        log.error("报表导出异常:", e);
    }
}

// 将指定位置指定名称的Excel导出到web
@GetMapping("/export2Web4File/{excelName}")
@ResponseBody
public String export2Web4File(HttpServletResponse response, @PathVariable String excelName) {
    try {
        return ExcelUtils.export2Web4File(response, path, excelName);
    } catch (Exception e) {
        log.error("文件导出异常：", e);
    }

    return "文件导出失败";
}

// easyexcel读取文件
@GetMapping("/read4File")
@ResponseBody
public String read4File() {
    String fileName = path + "用户表导入.xlsx";
    EasyExcel.read(fileName, User.class, new UserDataListener(userService)).sheet().doRead();
    return "读取成功";
}

// easyexcel上传文件
@PostMapping("/upload")
@ResponseBody
public String upload(MultipartFile file) throws IOException {
    EasyExcel.read(file.getInputStream(), User.class, new UserDataListener(userService)).sheet().doRead();
    return "上传成功";
}

非本人著作

EasyExcelUtils含调用