使用EasyExcel导出Excel文件

最简单的写

实体类

import com.alibaba.excel.annotation.ExcelProperty;
import com.alibaba.excel.annotation.write.style.ColumnWidth;
import com.alibaba.excel.annotation.write.style.ContentRowHeight;
import com.alibaba.excel.annotation.write.style.HeadRowHeight;
import com.alibaba.excel.metadata.BaseRowModel;
import lombok.AllArgsConstructor;
import lombok.Builder;
import lombok.Data;
import lombok.NoArgsConstructor;

import java.io.Serializable;

@Data
@NoArgsConstructor
@AllArgsConstructor
@Builder
@ContentRowHeight(15) //设定每一行的高度,不包含表头
@HeadRowHeight(30)  //设置 表头 高度
public class ExcelData extends BaseRowModel implements Serializable
{
    @ColumnWidth(15)  //列宽
    @ExcelProperty("姓名")
    private String userName;
    
    @ColumnWidth(15)
    @ExcelProperty("出生日期")
    @DateTimeFormat("yyyy-MM-dd") // "yyyy/MM/dd" "yyyy年MM月dd日HH时mm分ss秒" 等等格式都可以
    private String birth;

    @ColumnWidth(15)
    @ExcelProperty("工资")
    @NumberFormat(".##")  //#代表任意数字, 注意这里的日期格式和数字格式都必须是字符串类型的
    private String salary;
}

指定写入的列

@Data
public class IndexData {
    @ExcelProperty(value = "字符串标题", index = 0)
    private String string;
    @ExcelProperty(value = "日期标题", index = 1)
    private Date date;
    /**
     * 这里设置3 会导致第二列空的
     */
    @ExcelProperty(value = "数字标题", index = 3)
    private Double doubleData;
}

复杂头写入

@Data
public class ComplexHeadData {
    @ExcelProperty({"主标题", "字符串标题"})
    private String string;
    @ExcelProperty({"主标题", "日期标题"})
    private Date date;
    @ExcelProperty({"主标题", "数字标题"})
    private Double doubleData;
}

EasyExcelUtil

import com.alibaba.excel.EasyExcel;
import com.alibaba.excel.support.ExcelTypeEnum;
import com.alibaba.excel.write.metadata.style.WriteCellStyle;
import com.alibaba.excel.write.metadata.style.WriteFont;
import com.alibaba.excel.write.style.HorizontalCellStyleStrategy;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.springframework.stereotype.Component;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.List;

/**
 版本2.1.7 工具类(仅导出)中可自定义样式格式等
 **/
@Component
public class EasyExcelUtil {

    /**
     * 导出 Excel ：一个 sheet，带表头.
     *
     * @param response  HttpServletResponse
     * @param data      数据 list，每个元素为一个 BaseRowModel
     * @param fileName  导出的文件名
     * @param sheetName 导入文件的 sheet 名
     * @param model     映射实体类，Excel 模型
     * @throws Exception 异常
     */
    public void writeExcel(HttpServletResponse response, List<? extends Object> data, String fileName, String sheetName, Class model) throws Exception {

        // 头的策略
        WriteCellStyle headWriteCellStyle = new WriteCellStyle();
        //设置表头居中对齐
        headWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);
        // 颜色
        headWriteCellStyle.setFillForegroundColor(IndexedColors.PALE_BLUE.getIndex());
        WriteFont headWriteFont = new WriteFont();
        headWriteFont.setFontHeightInPoints((short) 10);
        // 字体
        headWriteCellStyle.setWriteFont(headWriteFont);
        headWriteCellStyle.setWrapped(true);
        // 内容的策略
        WriteCellStyle contentWriteCellStyle = new WriteCellStyle();
        //设置内容靠中对齐
        contentWriteCellStyle.setHorizontalAlignment(HorizontalAlignment.CENTER);
        // 这个策略是 头是头的样式 内容是内容的样式 其他的策略可以自己实现
        HorizontalCellStyleStrategy horizontalCellStyleStrategy = new HorizontalCellStyleStrategy(headWriteCellStyle, contentWriteCellStyle);
        // 这里 需要指定写用哪个class去写，然后写到第一个sheet，名字为模板 然后文件流会自动关闭
        EasyExcel.write(getOutputStream(fileName, response), model).excelType(ExcelTypeEnum.XLSX).sheet(sheetName).registerWriteHandler(horizontalCellStyleStrategy)
                //最大长度自适应 目前没有对应算法优化 建议注释掉不用 会出bug
//                .registerWriteHandler(new LongestMatchColumnWidthStyleStrategy())
                .doWrite(data);

    }

    /**
     * 导出文件时为Writer生成OutputStream.
     *
     * @param fileName 文件名
     * @param response response
     * @return ""
     */
    private OutputStream getOutputStream(String fileName, HttpServletResponse response) throws Exception {
        try {
            fileName = URLEncoder.encode(fileName, "UTF-8");
            response.setContentType("application/vnd.ms-excel");
            response.setCharacterEncoding("utf8");
            response.setHeader("Content-Disposition", "attachment; filename=" + fileName + ".xls");
            response.setHeader("Pragma", "public");
            response.setHeader("Cache-Control", "no-store");
            response.addHeader("Cache-Control", "max-age=0");
            return response.getOutputStream();
        } catch (IOException e) {
            throw new Exception("导出excel表格失败!", e);
        }
    }

}

控制层

import com.alibaba.excel.util.CollectionUtils;
import com.github.pagehelper.PageHelper;
import io.swagger.annotations.Api;
import io.swagger.annotations.ApiOperation;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import javax.servlet.http.HttpServletResponse;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

@Api(tags = "数据导出--Excel")
@Controller
@RequestMapping("/export")
public class ExportController
{
    @Autowired
    private UserMapper userMapper;

    @Autowired
    private EasyExcelUtil excelUtil;

    @ApiOperation("数据导出")
    @GetMapping("/exportExcel")
    public void exportSysSystemExcel(HttpServletResponse response) throws Exception {
        try {
            // 查询总数并封装相关变量
            Integer totalRowCount = (int) userMapper.selectNormalUserCount();
            Integer pageSize = ExcelConstant.PER_WRITE_ROW_COUNT;
            Integer writeCount = totalRowCount % pageSize == 0 ? (totalRowCount / pageSize) : (totalRowCount / pageSize + 1);

            // 写数据
            for (int i = 0; i < writeCount; i++) {
                List<List<String>> dataList = new ArrayList<>();
                //查询并封装数据
                PageHelper.startPage(i + 1, pageSize);

                List<User> userList = userMapper.selectNormalUser();
                if (!CollectionUtils.isEmpty(userList)) {
                    userList.forEach(item -> {
                        dataList.add(Arrays.asList(
                                user.getBirthday() == null? "无" : user.getBirthday(),
                                user.getBirthday() == null? "无" : user.getBirthday(),
                                user.getSalary() == null? "无" : user.getSalary()
                        ));
                    });
                }
                excelUtil.writeExcel(response, dataList, "文件名称", "sheet1", ExcelData.class);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}