1. 依赖
我的项目是基于Spring Boot的，这里只贴出POI框架需要依赖的两个包，其他的都无所谓，只要能提供Controller让浏览器访问即可。在pom.xml配置文件中增加如下两个包：
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>4.1.2</version>
</dependency>
<!-- https://mvnrepository.com/artifact/org.apache.poi/poi-ooxml -->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>4.1.2</version>
</dependency>
2. 代码实现
package com.eg.wiener.controller;
import com.eg.wiener.dto.User;
import com.eg.wiener.utils.ExcelUtils;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.collections4.CollectionUtils;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.BorderStyle;
import org.apache.poi.ss.usermodel.Font;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.lang.reflect.Field;
import java.util.ArrayList;
import java.util.List;
import java.util.Objects;
import java.util.stream.Stream;
/**
* @author Wiener
* @date 2020/9/5
*/
@Slf4j
@RestController
@RequestMapping("/excel")
public class ExcelExportController {
private static HSSFWorkbook workbook = null;
// 代表一行记录
private static HSSFCell cell = null;
private static HSSFRow row = null;
@RequestMapping(value = "/exportExcel")
public Object exportExcel(HttpServletRequest request, HttpServletResponse response) throws Exception {
String fileSuffix = ".xls";
String fileName = "导出数据至Excel示例"+ "_" + (int) (Math.random() * 9000 + 1000) + ".xls";
//【1】创建excel
workbook = new HSSFWorkbook();
// 设置表头的类型
HSSFCellStyle style = setCellStyle(workbook);
// 创建一个sheet
HSSFSheet sheet = workbook.createSheet("sheet1");
try {
List<User> dataList = getUsers();
if (CollectionUtils.isNotEmpty(dataList)) {
//【2】 设置表头：对Excel每列命名
String[] tableHeader = Stream.of("编号", "姓名", "年龄").toArray(String[]::new);
// 设置Excel表头
row = ExcelUtils.getExcelRow(workbook, sheet, tableHeader);
//通过反射，获取POJO对象。由于同一个dataList中，POJO相同，故定义在for循环外部，提高遍历性能
Class cl = dataList.get(0).getClass();
//获取类的所有字段
Field[] fields = cl.getDeclaredFields();
//写入每一行的记录
for (int i = 0; i < dataList.size(); i++) {
//创建新的一行，递增
row = sheet.createRow(i + 1);
// 设置行高
row.setHeight((short) 400);
for (int j = 0; j < fields.length; j++) {
//设置字段可见，否则会报错，禁止访问
fields[j].setAccessible(true);
//创建单元格
cell = row.createCell(j);
cell.setCellValue(Objects.toString(fields[j].get(dataList.get(i)), ""));
cell.setCellStyle(style);
}
}
} else {
// 没有查到数据提示行
row = ExcelUtils.getNotResultInfoRow(workbook, sheet, "记录为空");
}
} catch (Exception e) {
log.error("导出数据失败：", e);
// 写入Excel失败原因
row = ExcelUtils.getNotResultInfoRow(workbook, sheet, "导出数据失败");
fileName = "导出数据失败";
}
fileName = fileName + "_" + (int) (Math.random() * 9000 + 1000) + fileSuffix;
//下载文件
ExcelUtils.outputExcelStream(request, response, workbook, fileName);
return "导出成功";
}
private List<User> getUsers() {
List<User> list = new ArrayList<>();
User aUser = new User();
aUser.setAge(18);
aUser.setId(1);
aUser.setName("Tony");
list.add(aUser);
aUser = new User();
aUser.setAge(21);
aUser.setId(2);
aUser.setName("Tom");
list.add(aUser);
aUser = new User();
aUser.setAge(20);
aUser.setId(3);
aUser.setName("店小二");
list.add(aUser);
return list;
}
private HSSFCellStyle setCellStyle(HSSFWorkbook myWorkbook) {
HSSFCellStyle style = myWorkbook.createCellStyle();
//设置自动换行
style.setWrapText(true);
style.setAlignment(HorizontalAlignment.CENTER);
//设置边框样式
style.setBorderTop(BorderStyle.THIN);
style.setBorderBottom(BorderStyle.THIN);
style.setBorderLeft(BorderStyle.THIN);
style.setBorderRight(BorderStyle.THIN);
//设置边框颜色
style.setTopBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
style.setBottomBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
style.setLeftBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
style.setRightBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
HSSFDataFormat format = workbook.createDataFormat();
// 设置文本格式
style.setDataFormat(format.getFormat("@"));
// 设置字体
HSSFFont font = workbook.createFont();
font.setColor(Font.COLOR_RED);
font.setFontName("宋体");
font.setFontHeightInPoints((short) 12);// 12号字体
style.setFont(font);
return style;
}
}
通过反射获取POJO对象，故传入不同类型的POJO对象的dataList就可以了。下面是依赖的一个工具类：
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.BorderStyle;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.net.URLEncoder;
/**
* 导出Excel工具类
*
* @author Wiener
* @date 2020/9/5
*/
@Slf4j
public class ExcelUtils {
/**
* 设置Excel表头
*
* @param workbook
* @param sheet
* @param tableHeader
* @return
*/
public static HSSFRow getExcelRow(HSSFWorkbook workbook, HSSFSheet sheet, String[] tableHeader) {
short cellNumber = (short) tableHeader.length;
// Excel的第一行表头
HSSFRow row = sheet.createRow(0);
// 设置行高
row.setHeight((short) 560);
// Excel的列
HSSFCell cell = null;
HSSFFont font = workbook.createFont();
// 粗体显示
font.setBold(Boolean.TRUE);
font.setFontHeightInPoints((short) 15);
// 设置单元格字体的颜色
font.setColor(HSSFFont.COLOR_NORMAL);
// 样式
HSSFCellStyle style = workbook.createCellStyle();
style.setAlignment(HorizontalAlignment.CENTER);
//设置边框样式
style.setBorderTop(BorderStyle.DOTTED);
style.setBorderBottom(BorderStyle.DOTTED);
style.setBorderLeft(BorderStyle.DOTTED);
style.setBorderRight(BorderStyle.DOTTED);
//设置边框颜色
style.setTopBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
style.setBottomBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
style.setLeftBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
style.setRightBorderColor(HSSFColor.HSSFColorPredefined.BLACK.getIndex());
for (int k = 0; k < cellNumber; k++) {
int i = 0;
i += k;
short b = 6000;
cell = row.createCell(i); // 创建第0行第k列
cell.setCellValue(tableHeader[k]); // 设置第0行第k列的值
sheet.setColumnWidth(i, b); // 设置列的宽度
style.setFont(font); // 设置字体风格
cell.setCellStyle(style);
}
return row;
}
/**
* 设置Excel未获取数据提示行
*
* @param workbook
* @param sheet
* @return
*/
public static HSSFRow getNotResultInfoRow(HSSFWorkbook workbook, HSSFSheet sheet, String message) {
// Excel的第一行表头
HSSFRow row = sheet.createRow(0);
// Excel的列
HSSFCell cell = null;
// 设置表头的类型
HSSFCellStyle style = workbook.createCellStyle();
//设置自动换行
style.setWrapText(true);
style.setAlignment(HorizontalAlignment.CENTER);
// 没有查到数据
row = sheet.createRow((short) (0)); // 创建第j+1行
row.setHeight((short) 1000); // 设置行高
sheet.setColumnWidth(0, 10000);
cell = row.createCell(0); // 创建第i+1行第1列
cell.setCellValue(message);//
cell.setCellStyle(style); // 设置风格
return row;
}
/**
* 下载EXCEL,对不同浏览器做中文名称兼容<br/>
* 如果不对文件名进行编码处理，那么有些浏览器无法识别下载文件
*
* @param request
* @param response
* @param workbook
* @param fileName
*/
public static void outputExcelStream(HttpServletRequest request, HttpServletResponse response, HSSFWorkbook workbook, String fileName) {
OutputStream out = null;
try {
String excelFileName = fileName + "_" + (int) (Math.random() * 9000 + 1000) + ".xls";
if (isMsBrowser(request)) {
// ie,edge 浏览器
excelFileName = URLEncoder.encode(excelFileName, "UTF-8");
} else {
//其他的浏览器
excelFileName = new String(excelFileName.getBytes("UTF-8"), "iso-8859-1");
}
//输出流对象
out = response.getOutputStream();
// 设置文件头编码方式和文件名
response.setHeader("Content-Disposition", "attachment;filename=" + excelFileName);
// 设置类型
response.setContentType("application/msexcel;charset=UTF-8");
response.setHeader("Pragma", "No-cache");
response.setHeader("Cache-Control", "no-cache");
response.setDateHeader("Expires", 0);
workbook.write(out);
out.flush();
workbook.write(out);
} catch (IOException e) {
log.error("下载EXCEL失败，", e);
} finally {
try {
if (out != null) {
out.close();
}
} catch (IOException e) {
log.error("下载EXCEL关闭文件流失败，", e);
}
}
}
//判断是否是IE浏览器
private static boolean isMsBrowser(HttpServletRequest request) {
String userAgent = request.getHeader("User-Agent");
if (StringUtils.isBlank(userAgent)) {
return false;
}
String[] IEBrowserSignals = {"msie", "trident", "edge"};
for (String signal : IEBrowserSignals) {
if (userAgent.toLowerCase().contains(signal)) {
return true;
}
}
return false;
}
}
在使用的时候，仅仅需要传入不同的表头集合、实体类集合，就能实现需求，这就是封装的魅力所在。