poi 灵活导出excel（有这一篇即可~~~~）
大家在开发项目的时候，但凡涉及数据多而杂的时候或多或少需要导出excel，用什么的工具类这时候就很烦恼了，接下来的工具类傻瓜式一键生成大家需要的excel。
1.依赖
Apache POI是Apache软件基金会的开放源码函式库，POI提供API给Java程序对Microsoft Office格式档案读和写的功能。
HSSF 是Horrible SpreadSheet Format的缩写，通过HSSF，你可以用纯Java代码来读取、写入、修改Excel文件。
HSSF 为读取操作提供了两类API：usermodel和eventusermodel，即“用户模型”和“事件-用户模型”
这里采用poi依赖
org.apache.poi
poi-ooxml
3.17
2.工具类
构建头部
public class ReflectUtil {
public static List[] getHeadAndFields(Class clazz){
List[] list = new List[2];
List headerList = Lists.newArrayList();
List fieldList = Lists.newArrayList();
List fields = Arrays.stream(clazz.getDeclaredFields()).
filter(a -> a.getAnnotation(com.xwcx.culture_city.util.Export.class) != null)
.sorted((field1,field2) -> {
com.xwcx.culture_city.util.Export export1 = field1.getAnnotation(com.xwcx.culture_city.util.Export.class);
com.xwcx.culture_city.util.Export export2 = field1.getAnnotation(com.xwcx.culture_city.util.Export.class);
return export1.sort() - export2.sort();
})
.collect(Collectors.toList());
if(fields.size() == 0){
return list;
}
for(int i = 0 ; i < fields.size() ;i ++){
Field field = fields.get(i);
com.xwcx.culture_city.util.Export export = field.getAnnotation(com.xwcx.culture_city.util.Export.class);
if(export != null){
headerList.add(i,export.name());
fieldList.add(i,field.getName());
}
}
list[0] = headerList;
list[1] = fieldList;
return list;
}
public static void main(String[] args) {
}
} 循环表格，渲染数据
package com.xwcx.culture_city.util;
import org.apache.commons.beanutils.PropertyUtilsBean;
import org.apache.commons.lang3.StringUtils;
import org.apache.poi.hssf.util.HSSFColor;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.beans.PropertyDescriptor;
import java.io.FileOutputStream;
import java.io.IOException;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
/**
* @Description
* @Author cheng
* @Date2020-01-16 11:08
* @Version V1.0
**/
public class ExcelUtil {
//单个sheet最多写入行数
private static final int SHEET_MAX_COUNT = 1000000;
/**
* 创建Workbook
* @return
*/
public static Workbook createWorkbook(){
Workbook wb = new SXSSFWorkbook(100);
CellStyle hcs = wb.createCellStyle();
hcs.setBorderBottom(BorderStyle.THIN);
hcs.setBorderLeft(BorderStyle.THIN);
hcs.setBorderRight(BorderStyle.THIN);
hcs.setBorderTop(BorderStyle.THIN);
hcs.setAlignment(HorizontalAlignment.CENTER);
Font hfont = wb.createFont();
hfont.setFontName("宋体");
// 设置字体大小
hfont.setFontHeightInPoints((short) 16);
// 加粗
hfont.setBold(true);
hcs.setFont(hfont);
CellStyle tcs = wb.createCellStyle();
tcs.setBorderBottom(BorderStyle.THIN);
tcs.setBorderLeft(BorderStyle.THIN);
tcs.setBorderRight(BorderStyle.THIN);
tcs.setBorderTop(BorderStyle.THIN);
Font tfont = wb.createFont();
tfont.setFontName("宋体");
// 设置字体大小
tfont.setFontHeightInPoints((short) 12);
// 加粗
tfont.setBold(true);
tcs.setFont(tfont);
CellStyle cs = wb.createCellStyle();
cs.setBorderBottom(BorderStyle.THIN);
cs.setBorderLeft(BorderStyle.THIN);
cs.setBorderRight(BorderStyle.THIN);
cs.setBorderTop(BorderStyle.THIN);
Font font = wb.createFont();
font.setFontName("宋体");
// 设置字体大小
font.setFontHeightInPoints((short) 12);
// font.setColor(HSSFColor.RED.index);
cs.setFont(font);
CellStyle cs1 = wb.createCellStyle();
cs1.setBorderBottom(BorderStyle.THIN);
cs1.setBorderLeft(BorderStyle.THIN);
cs1.setBorderRight(BorderStyle.THIN);
cs1.setBorderTop(BorderStyle.THIN);
Font font1 = wb.createFont();
font1.setFontName("宋体");
// 设置字体大小
font1.setFontHeightInPoints((short) 12);
font1.setColor(HSSFColor.HSSFColorPredefined.RED.getIndex());
cs1.setFont(font1);
return wb;
}
public static void exportExcel(String title, List headers, List fields, int startRow, Workbook wb, List data) throws IOException {
Sheet sheet = null;
startRow = startRow > 0 ? startRow + 2 : startRow;
// 行号、页码、列数
int index = startRow, pageRowNo = startRow, columnCount = headers.size();
for (T obj : data) {
int sheetIndex = index/SHEET_MAX_COUNT;
if (index % SHEET_MAX_COUNT == 0) {
sheet = wb.createSheet(title + "_" + (sheetIndex + 1));
sheet = wb.getSheetAt(sheetIndex);
// 设置表标题是否有表格边框
sheet.setDisplayGridlines(false);
// pageRowNo = 2;
pageRowNo = 1;
createHeader(sheet, title, headers);
}else{
sheet = wb.getSheetAt(sheetIndex);
}
index++;
Map map = obj instanceof Map ? (Map) obj : beanToMap(obj);
// 新建行对象
Row nRow = sheet.createRow(pageRowNo++);
int k = 0;
for (int j = 0; j < columnCount; j++) {
boolean flag = true;
Cell cell = nRow.createCell(j);
sheet.setColumnWidth(j, 20 * 256);
if ("问卷列表".equals(title)) {
String[] answer = {"A", "O", "A", "D", "A", "A", "A", "A", "A", "C", "A", "A", "A", "A", "A", "A", "C", "A"};
if(j >= 11 && j < 29 ){
if((!answer[k].equals(map.get(fields.get(j)))) && k!=1){
flag = false;
}
k++;
}
}
setCellValue(sheet, cell, map.get(fields.get(j)),flag);
}
}
}
/**
* write Workbook
* @param wb
* @param filePath
* @throws IOException
*/
public static void writeWorkbook(Workbook wb, String filePath, String fileName)throws IOException{
FileOutputStream fos = new FileOutputStream(filePath + fileName);
wb.write(fos);
fos.flush();
fos.close();
wb.close();
}
/**
* responseWorkbook
* @param title 标题
* @param wb 流
* @param request http请求
* @param response http返回
* @throws IOException
*/
public static void responseWorkbook(String title, Workbook wb, HttpServletRequest request, HttpServletResponse response)throws IOException{
String sFileName = title + ".xlsx";
// 火狐浏览器导出excel乱码
String agent = request.getHeader("User-Agent");
// 判断是否火狐浏览器
boolean isFirefox = agent != null && agent.contains("Firefox");
if (isFirefox) {
sFileName = new String(sFileName.getBytes("UTF-8"), "ISO-8859-1");
} else {
sFileName = URLEncoder.encode(sFileName, "UTF8");
}
// response.setHeader("Content-Disposition", "attachment; filename=".concat(sFileName));
// response.setHeader("Connection", "close");
// response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
response.setContentType("application/vnd.ms-excel;chartset=utf-8");
response.setCharacterEncoding("UTF-8");
response.setHeader("Content-Disposition","attachment; filename=" + sFileName);
wb.write(response.getOutputStream());
}
/**
* 设置单元格的值
* @param cell 单元格
* @param cellVal 单元格的值
*/
public static void setCellValue(Sheet sheet, Cell cell, Object cellVal,boolean flag){
if(cellVal == null){
cell.setCellValue("");
}else if (String.class.equals(cellVal.getClass())){
cell.setCellValue((String)cellVal);
}else if(Integer.class.equals(cellVal.getClass()) || int.class.equals(cellVal.getClass())){
cell.setCellValue(Integer.valueOf(cellVal.toString()));
}else if(Long.class.equals(cellVal.getClass()) || long.class.equals(cellVal.getClass())){
cell.setCellValue(Integer.valueOf(cellVal.toString()));
}else if(Double.class.equals(cellVal.getClass()) || double.class.equals(cellVal.getClass())){
cell.setCellValue(Double.valueOf(cellVal.toString()));
}else if(Float.class.equals(cellVal.getClass()) || float.class.equals(cellVal.getClass())){
cell.setCellValue(Float.valueOf(cellVal.toString()));
}else if(BigDecimal.class.equals(cellVal.getClass())){
cell.setCellValue(new BigDecimal(cellVal.toString()).doubleValue());
}else if(Date.class.equals(cellVal.getClass())){
cell.setCellValue(DateUtils.format((Date)cellVal,DateUtils.DATE_TIME_PATTERN));
}else{
cell.setCellValue(cellVal.toString());
}
if(flag == true){
cell.setCellStyle(sheet.getWorkbook().getCellStyleAt(3));
}else{
cell.setCellStyle(sheet.getWorkbook().getCellStyleAt(4));
}
System.out.println("");
}
/**
* JavaBean转Map
*
* @param obj 实体转换对象
* @return
*/
public static Map beanToMap(Object obj) {
Map params = new HashMap<>(0);
try {
PropertyUtilsBean propertyUtilsBean = new PropertyUtilsBean();
PropertyDescriptor[] descriptors = propertyUtilsBean.getPropertyDescriptors(obj);
for (int i = 0; i < descriptors.length; i++) {
String name = descriptors[i].getName();
if (!StringUtils.equals(name, "class")) {
params.put(name, propertyUtilsBean.getNestedProperty(obj, name));
}
}
} catch (Exception e) {
}
return params;
}
/**
* 创建表头
* @param sheet sheet页
* @param headers 头部信息
*/
private static void createHeader(Sheet sheet, String title, List headers){
//设置标题
// Row tRow = sheet.createRow(0);
// Cell hc = tRow.createCell(0);
// hc.setCellValue(new XSSFRichTextString(title));
// // 合并标题行：起始行号，终止行号， 起始列号，终止列号
// sheet.addMergedRegion(new CellRangeAddress(0, 0, 0, headers.size() - 1));
// hc.setCellStyle(sheet.getWorkbook().getCellStyleAt(1));
//设置表头
Row nRow = sheet.createRow(0);
for (int i = 0; i < headers.size(); i++) {
Cell cell = nRow.createCell(i);
cell.setCellValue(headers.get(i));
cell.setCellStyle(sheet.getWorkbook().getCellStyleAt(2));
}
}
}
由于方法工具类调用的是 SXSSFWorkbook！所以导出的文件类型是.xlsx结尾，顾名思义是excel2003版本以后的，如若需要.xls结尾需要自行修改。
3.调用
String title = "用户管理";
//UserListVo 实体类对象需要额外添加一个注解
List[] headAndFields = ReflectUtil.getHeadAndFields(UserListVo.class);
List headers = headAndFields[0];
List fields = headAndFields[1];
Workbook workbook = ExcelUtil.createWorkbook();
//该集合就是自己搜索出来的vo或者do集合
List listVoList = null;
int startRow = 0;
ExcelUtil.exportExcel(title, headers, fields, startRow, workbook, listVoList);
ExcelUtil.responseWorkbook(title, workbook, request, response);
workbook.close(); 仅仅是实体类对象是不够的，我们需要针对需要导出的excel表头去确定导出字段。
@Export(name = "用户名",sort =1)
@Export(name = "用户名",sort =1)
private String name;这个注解可以根据我们业务需要的表头确定需要的字段，表头顺序根据注解对应字段的顺序。
以上！就是针对导出excel需要的工具类，调用方法。很简单，如有问题，欢迎大家评论区讨论！