工具类

导出工具类

package com.epoch.boot.customproject.demand.util;

import org.apache.poi.hssf.usermodel.*;

import javax.servlet.http.HttpServletResponse;
import java.util.List;
import java.util.Map;

public class CustomExcelUtils {

    public static void exportExcel(HttpServletResponse response, String fileName, List<Map> dataList, String[] titleName, String[] titleCode) throws Exception {
        if (CustomUtils.isEmpty(dataList)) {
            response.addHeader("Content-Type", "application/json;charset=UTF-8");
            response.getWriter().print("没有可导出数据！");
            return;
        }
        int fileSize = 65535;
        double sheetNum = Math.ceil(dataList.size() / new Integer(fileSize).doubleValue());
        HSSFWorkbook wb = new HSSFWorkbook();
        try {
            for (int i = 0; i < sheetNum; i++) {
                HSSFSheet sheet = wb.createSheet(fileName + (i + 1));
                if (sheetNum == 1) {
                    fillSheet(sheet, dataList, titleName, titleCode);
                } else {
                    int subSize = i + 1 == sheetNum ? dataList.size() : fileSize;
                    List<Map> subList = dataList.subList(i * fileSize, subSize);
                    fillSheet(sheet, subList, titleName, titleCode);
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        response.setContentType("application/octet-stream;charset=utf-8");
        response.setHeader("Content-disposition", "attachment; filename=" + new String(fileName.getBytes(), "iso-8859-1") + ".xls");
        response.flushBuffer();
        wb.write(response.getOutputStream());
    }

    public static void fillSheet(HSSFSheet sheet, List<Map> dataList, String[] titleName, String[] titleCode) {
        //标题行
        HSSFRow titleRow = sheet.createRow(0);

        //添加标题行数据
        for (int i = 0; i < titleName.length; i++) {
            titleRow.createCell(i).setCellValue(new HSSFRichTextString(titleName[i]));
        }

        //插入数据
        for (int i = 0; i < dataList.size(); i++) {
            Map data = dataList.get(i);
            HSSFRow row = sheet.createRow(i + 1);
            for (int j = 0; j < titleCode.length; j++) {
                if (CustomUtils.isNotEmpty(data.get(titleCode[j]))) {
                    row.createCell(j).setCellValue(data.get(titleCode[j]).toString());
                }
            }
        }
    }

}

判空工具类

package com.epoch.boot.customproject.demand.util;

import org.springframework.lang.Nullable;

import java.util.Collection;
import java.util.Map;

public class CustomUtils {

    public static boolean isEmpty(Object obj) {
        return (obj == null || "".equals(obj) || "null".equals(obj));
    }

    public static boolean isNotEmpty(Object obj) {
        return !isEmpty(obj);
    }

    public static boolean isEmpty(@Nullable Map<?, ?> map) {
        return (map == null || map.isEmpty());
    }

    public static boolean isNotEmpty(@Nullable Map<?, ?> map) {
        return !isEmpty(map);
    }

    public static boolean isEmpty(@Nullable Collection<?> collection) {
        return (collection == null || collection.isEmpty());
    }

    public static boolean isNotEmpty(@Nullable Collection<?> collection) {
        return !isEmpty(collection);
    }
}