添加maven依赖：

<!-- poi -->
<dependency><groupId>org.apache.poi</groupId><artifactId>poi-ooxml</artifactId><version>3.17-beta1</version>
</dependency><!-- fast json -->
<dependency> <groupId>com.alibaba</groupId><artifactId>fastjson</artifactId><version>1.2.31</version>
</dependency>

主要代码：

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.liyang.entity.UserEntity;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.DataFormat;
import org.apache.poi.ss.usermodel.Font;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;import javax.servlet.http.HttpServletResponse;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.List;/**
 * 导出excel工具
 *
 * @author 李阳
 * @mail ly_triangle@126.com
 * 15002992382
 * 2017-07-24
 */
public class ExcelUtil {/**
     * 根据给定的数据在前端页面导出excel
     *
     * @param fileName 文件名
 * @param wb 工作簿
     * @param response
     * @throws IOException
     */
    public static void exportDatasExcel(String fileName, Workbook wb, HttpServletResponse response) throws IOException {        //清空前端缓存
        response.reset();         //指定前端文件mime类型  response.setContentType("application/vnd.ms-excel;charset=utf-8");response.setHeader("Content-Disposition", "attachment;fileName="+ new String(replaceSpecialChars（fileName）.getBytes(), "iso8859-1")+ ".xlsx");//字节数组输出流
        ByteArrayOutputStream out = new ByteArrayOutputStream();//将工作簿写进字节数组输出流中
        wb.write(out);//创建字节数组输入流，将输出流中的数据写进该输入流中，最后创建输入流的缓冲流，便于读取数据
        BufferedInputStream bufferIn = new BufferedInputStream(new ByteArrayInputStream(out.toByteArray()));//获得response输出流，并获得输出流的缓冲流，便于写入数据
        BufferedOutputStream bufferOut = new BufferedOutputStream(response.getOutputStream());//每次输出文件1000字节长度数据到输出流
        byte[] buffer = new byte[1000];int bytesRead;//读取输入缓冲流中的数据，经过缓冲输出流发送给前端下载
        while (-1 != (bytesRead = bufferIn.read(buffer))) {bufferOut.write(buffer, 0, bytesRead);}bufferOut.flush();bufferIn.close();bufferOut.close();}/**
     * 创建excel表格(记录性结果)
     *
     * @param titles  标题集合
     * @param keys    key值集合，用于读取json对象中的数据
     * @param objects 数据对象集合
     * @return
     */
    private static Workbook buildWorkbook(List<String> titles, List<String> keys, List<Object> objects, String fileName) {//创建工作簿
        Workbook wb = new XSSFWorkbook();  //or new HSSFWorkbook();

        //创建表格
        Sheet sheet = wb.createSheet(replaceSpecialChars(fileName));//第一行
        Row row = sheet.createRow(0);//第二行
        Row row1 = sheet.createRow(1);//创建数据单元格样式       CellStyle style = creatStyle(wb);//创建标题单元格样式CellStyle titleStyle = creatTitleStyle(wb);Cell cell;Cell cell1;//遍历标题，标题占两行
        for (int t = 0; t < titles.size(); t++) {//创建标题单元格并设置标题单元格的值
            cell = row.createCell(t);cell.setCellValue(titles.get(t));//创建第二行单元格
            cell1 = row1.createCell(t);//合并上下单元格（标题占两行）
            sheet.addMergedRegion(new CellRangeAddress(0, 1, t, t));//对单元格使用样式
            cell.setCellStyle(titleStyle );cell1.setCellStyle(titleStyle );}//将对象集合转换成json对象数组
        JSONArray array = JSON.parseArray(JSON.toJSONString(objects));//遍历json对象数组，将数据写进excel中
        for (int r = 2; r < array.size() + 2; r++) {JSONObject o = array.getJSONObject(r - 2);//创建行
            row = sheet.createRow(r);//创建行单元格，并赋值
            for (int c = 0; c < keys.size(); c++) {String value = o.get(keys.get(c)) == null ? "" : o.get(keys.get(c)).toString();cell = row.createCell(c);cell.setCellValue(value);cell.setCellStyle(style);}}// 最后一列宽自适应sheet.autoSizeColumn(titles.size()-1);//获得工作簿
        return wb;}

创建复杂excel表格（非记录性数据，需要一定模板）：

/**
 * 动态生成复杂excel
 *
 * @param rowSize    行数
 * @param columnSize 列数
 * @param models     单元格实例集合（每一个单元格（包括合并的单元格）起止行列四个索引和单元格的值）
 * @param fileName   文件名
 * @return
 */
public static Workbook buildWorkbook2(Integer rowSize, Integer columnSize, List<CellModel> models, String fileName) {Workbook wb = new XSSFWorkbook();Sheet sheet = wb.createSheet(replaceSpecialChars（fileName）);CellStyle style = creatStyle(wb);CellStyle titleStyle = creatTitleStyle(wb);Row row;Cell cell;//创建空表格
    for (int r = 0; r < rowSize; r++) {row = sheet.createRow(r);for (int c = 0; c < columnSize; c++) {cell = row.createCell(c);if (0 == r || 1 == r) {cell.setCellStyle(titleStyle);} else {cell.setCellStyle(style);}}}//单元格赋值并合并单元格
    models.forEach(c -> {Integer rowBegin = c.getRowBegin();Integer rowEnd = c.getRowEnd();Integer columnBegin = c.getColumnBegin();Integer columnEnd = c.getColumnEnd();sheet.getRow(rowBegin).getCell(columnBegin).setCellValue(c.getValue().toString());if (rowBegin.intValue() != rowEnd.intValue() || columnBegin.intValue() != columnEnd.intValue())sheet.addMergedRegion(new CellRangeAddress(rowBegin, rowEnd, columnBegin, columnEnd));});short height = sheet.getDefaultRowHeight();sheet.setDefaultRowHeight((short) (height * 1.7));sheet.setDefaultColumnWidth(15);return wb;
}

单元格对象：

public class CellModel {private Object value = ""; //单元格值
    private Integer rowBegin; //开始行索引
    private Integer rowEnd;  //结束行索引
    private Integer columnBegin;  //开始列索引
    private Integer columnEnd;  //结束列索引.....略

创建标题样式：

/**
 * create title style
 * @param wb
 * @return
 */
private static CellStyle creatTitleStyle(Workbook wb) {Font font = wb.createFont();font.setFontHeightInPoints((short) 12);font.setFontName("黑体");font.setBold(true);CellStyle titleStyle = wb.createCellStyle();titleStyle.setAlignment(HorizontalAlignment.CENTER);titleStyle.setVerticalAlignment(VerticalAlignment.CENTER);titleStyle.setBorderTop(BorderStyle.THIN);titleStyle.setBorderBottom(BorderStyle.THIN);titleStyle.setBorderLeft(BorderStyle.THIN);titleStyle.setBorderRight(BorderStyle.THIN);//背景色titleStyle.setFillForegroundColor(HSSFColor.HSSFColorPredefined.SEA_GREEN.getIndex());titleStyle.setFillPattern(FillPatternType.SOLID_FOREGROUND);titleStyle.setFont(font);return titleStyle;
}

创建数据样式：

private static CellStyle creatStyle(Workbook wb) {Font font = wb.createFont();//字号font.setFontHeightInPoints((short) 12);//字体font.setFontName("宋体");   //斜体//font.setItalic(true);//加粗//font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);//创建样式CellStyle style = wb.createCellStyle();// 给样式指定字体style.setFont(font);//纵横向居中style.setAlignment(HorizontalAlignment.CENTER);style.setVerticalAlignment(VerticalAlignment.CENTER);//四周边框style.setBorderTop(BorderStyle.THIN);style.setBorderBottom(BorderStyle.THIN);style.setBorderLeft(BorderStyle.THIN);style.setBorderRight(BorderStyle.THIN);return style;
}

文件名特殊字符处理（特殊字符统一用空格替换）

private static String replaceSpecialChars(String fileName) {return fileName.replaceAll("：", " ").replaceAll(":", " ").replaceAll("？", " ").replaceAll("\\?", " ").replaceAll("\\*", " ").replaceAll("]", " ").replaceAll("\\[", " ").replaceAll("“", " ").replaceAll("”", " ").replaceAll("\"", " ").replaceAll("\\|", " ").replaceAll(">", " ").replaceAll("<", " ").replaceAll("\\\\", " ").replaceAll("/", " ");
}

测试1（记录性结果）：

/*** test
     */
    public static void main(String[] args) throws IOException {//构造数据对象集合
        List list = Arrays.asList(new UserEntity("kevin", "lee", 5),new UserEntity("david", "lee", null),new UserEntity("kavin", "", 6),new UserEntity("kavein", "lee", 65));//构造标题和key值列表，生成工作簿
        Workbook wb = buildWorkbook(Arrays.asList("姓名", "全名", "年龄"),Arrays.asList("stageName", "fullName", "sex"), list);//生成服务器本地文件，如需输出到前端，只需要调用exportDatasExcel方法即可
        FileOutputStream fileOut = new FileOutputStream("dataExcel.xlsx");wb.write(fileOut);fileOut.close();wb.close();}

测试2（复杂结果）：

public static void main(String[] args) throws IOException {//构造数据对象集合
    List list = new ArrayList();list.add(new CellModel("标题", 0, 1, 0, 3));
    list.add(new CellModel("购买渠道", 2, 26, 0, 0));list.add(new CellModel("微信", 2, 13, 1, 1));list.add(new CellModel("网站", 14, 26, 1, 1));
    list.add(new CellModel("微信平台名称", 2, 3, 2, 3));list.add(new CellModel("大秦帝国", 4, 13, 2, 3));list.add(new CellModel("网站平台名称", 14, 15, 2, 3));list.add(new CellModel("饿狼传说", 16, 26, 2, 3));//构造标题和key值列表，生成工作簿
    Workbook wb = buildWorkbook2(27, 5, list, "domo");//生成服务器本地文件，如需输出到前端，只需要调用exportDatasExcel方法即可
    FileOutputStream fileOut = new FileOutputStream("domo.xlsx");wb.write(fileOut);fileOut.close();wb.close();
}

测试结果：

记录性结果excel：

复杂excel结果：