导出的时候如果对Excel版本要求为xls版本时，大数据量时会比较慢，甚至出现内存溢出，这里没有去研究怎么实现xls实现大数据量导出，甚至轮子中连达到一定数量就新建sheet的操作都没有，因为没有必要，大数据我会选择SXSSF导出。
当导出为xlsx时，我没有选择用XSSF，而是选择的SXSSF，这样能减少内存消耗，降低了内存溢出的风险。
导出Excel轮子
package me.cf81.onestep.util;
import me.cf81.onestep.epc.Exceptions;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.usermodel.HSSFPalette;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.net.URLEncoder;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
/**
* @Author: yh
* @Description: excel导出轮子
* @Date: Created in 14:29 2018/11/27.
*/
public class ExcelExport {
private static final Logger logger = LoggerFactory.getLogger(ExcelExport.class);
HttpServletResponse response;
// 文件名
private String fileName;
//文件保存路径
private String fileDir;
//sheet名
private String sheetName;
//表头字体
private String titleFontType = "Arial Unicode MS";
//表头背景色
private String titleBackColor = "C1FBEE";
//表头字号
private short titleFontSize = 12;
//添加自动筛选的列 如 A:M
private String address = "";
//正文字体
private String contentFontType = "Arial Unicode MS";
//正文字号
private short contentFontSize = 12;
//Float类型数据小数位
private String floatDecimal = "0.00";
//Double类型数据小数位
private String doubleDecimal = "0.00";
//设置列的公式
private String colFormula[] = null;
DecimalFormat floatDecimalFormat = new DecimalFormat(floatDecimal);
DecimalFormat doubleDecimalFormat = new DecimalFormat(doubleDecimal);
private HSSFWorkbook workbook = null;
public ExcelExport() {
}
public ExcelExport(String fileDir, String sheetName) {
this.fileDir = fileDir;
this.sheetName = sheetName;
workbook = new HSSFWorkbook();
}
public ExcelExport(HttpServletResponse response, String fileName, String sheetName) {
this.fileName = fileName;
this.response = response;
this.sheetName = sheetName;
workbook = new HSSFWorkbook();
}
/**
* 设置表头字体.
*
* @param titleFontType
*/
public void setTitleFontType(String titleFontType) {
this.titleFontType = titleFontType;
}
/**
* 设置表头背景色.
*
* @param titleBackColor 十六进制
*/
public void setTitleBackColor(String titleBackColor) {
this.titleBackColor = titleBackColor;
}
/**
* 设置表头字体大小.
*
* @param titleFontSize
*/
public void setTitleFontSize(short titleFontSize) {
this.titleFontSize = titleFontSize;
}
/**
* 设置表头自动筛选栏位,如A:AC.
*
* @param address
*/
public void setAddress(String address) {
this.address = address;
}
/**
* 设置正文字体.
*
* @param contentFontType
*/
public void setContentFontType(String contentFontType) {
this.contentFontType = contentFontType;
}
/**
* 设置正文字号.
*
* @param contentFontSize
*/
public void setContentFontSize(short contentFontSize) {
this.contentFontSize = contentFontSize;
}
/**
* 设置float类型数据小数位 默认.00
*
* @param doubleDecimal 如 ".00"
*/
public void setDoubleDecimal(String doubleDecimal) {
this.doubleDecimal = doubleDecimal;
}
/**
* 设置doubel类型数据小数位 默认.00
*
* @param floatDecimalFormat 如 ".00
*/
public void setFloatDecimalFormat(DecimalFormat floatDecimalFormat) {
this.floatDecimalFormat = floatDecimalFormat;
}
/**
* 设置列的公式
*
* @param colFormula 存储i-1列的公式 涉及到的行号使用@替换 如A@+B@
*/
public void setColFormula(String[] colFormula) {
this.colFormula = colFormula;
}
/**
* 写excel.
* xls方式
*
* @param titleColumn 对应bean的属性名
* @param titleName excel要导出的列名
* @param titleSize 列宽
* @param dataList 数据
*/
public void writeExcel(String titleColumn[], String titleName[], int titleSize[], List<?> dataList) {
//添加Worksheet（不添加sheet时生成的xls文件打开时会报错)
Sheet sheet = workbook.createSheet(this.sheetName);
//新建文件
OutputStream out = null;
try {
if (fileDir != null) {
//有文件路径
out = new FileOutputStream(fileDir);
} else {
//否则，直接写到输出流中
out = response.getOutputStream();
fileName = fileName + ".xls";
response.setContentType("application/msexcel;charset=UTF-8");
response.setHeader("Content-Disposition", "attachment; filename="
+ URLEncoder.encode(fileName, "UTF-8"));
}
//写入excel的表头
Row titleNameRow = workbook.getSheet(sheetName).createRow(0);
//设置样式
CellStyle titleStyle = workbook.createCellStyle();
titleStyle = (HSSFCellStyle) setFontAndBorder(titleStyle, titleFontType, (short) titleFontSize);
titleStyle = (HSSFCellStyle) setColor(titleStyle, titleBackColor, (short) 10);
for (int i = 0; i < titleName.length; i++) {
sheet.setColumnWidth(i, titleSize[i] * 256); //设置宽度
Cell cell = titleNameRow.createCell(i);
cell.setCellStyle(titleStyle);
cell.setCellValue(titleName[i].toString());
}
//为表头添加自动筛选
if (!"".equals(address)) {
CellRangeAddress c = (CellRangeAddress) CellRangeAddress.valueOf(address);
sheet.setAutoFilter(c);
}
//通过反射获取数据并写入到excel中
if (dataList != null && dataList.size() > 0) {
//设置样式
HSSFCellStyle dataStyle = workbook.createCellStyle();
titleStyle = (HSSFCellStyle) setFontAndBorder(titleStyle, contentFontType, (short) contentFontSize);
if (titleColumn.length > 0) {
for (int rowIndex = 1; rowIndex <= dataList.size(); rowIndex++) {
Object obj = dataList.get(rowIndex - 1); //获得该对象
Class clsss = obj.getClass(); //获得该对对象的class实例
Row dataRow = workbook.getSheet(sheetName).createRow(rowIndex);
for (int columnIndex = 0; columnIndex < titleColumn.length; columnIndex++) {
String title = titleColumn[columnIndex].toString().trim();
if (!"".equals(title)) { //字段不为空
//使首字母大写
String UTitle = Character.toUpperCase(title.charAt(0)) + title.substring(1, title.length()); // 使其首字母大写;
String methodName = "get" + UTitle;
// 设置要执行的方法
Method method = clsss.getDeclaredMethod(methodName);
//获取返回类型
String returnType = method.getReturnType().getName();
Object object = method.invoke(obj);
String data = method.invoke(obj) == null ? "" : object.toString();
Cell cell = dataRow.createCell(columnIndex);
if (data != null && !"".equals(data)) {
if ("int".equals(returnType)) {
cell.setCellValue(Integer.parseInt(data));
} else if ("long".equals(returnType)) {
cell.setCellValue(Long.parseLong(data));
} else if ("float".equals(returnType)) {
cell.setCellValue(floatDecimalFormat.format(Float.parseFloat(data)));
} else if ("double".equals(returnType)) {
cell.setCellValue(doubleDecimalFormat.format(Double.parseDouble(data)));
} else if (Date.class.getName().equals(returnType)) {
cell.setCellValue(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(object));
} else {
cell.setCellValue(data);
}
}
} else { //字段为空 检查该列是否是公式
if (colFormula != null) {
String sixBuf = colFormula[columnIndex].replace("@", (rowIndex + 1) + "");
Cell cell = dataRow.createCell(columnIndex);
cell.setCellFormula(sixBuf);
}
}
}
}
}
}
workbook.write(out);
} catch (Exception e) {
e.printStackTrace();
throw Exceptions.ERROR.buildException();
} finally {
if (out != null) {
try {
out.close();
} catch (IOException e) {
logger.debug("导出写Excel异常");
}
}
}
}
/**
* xlsx方式
*
* @param response
* @param fileName
* @param titleColumn
* @param titleName
* @param titleSize
* @param dataList
*/
public void writeBigExcel(HttpServletResponse response, String fileName, String titleColumn[],
String titleName[], int titleSize[], List<?> dataList) {
try {
SXSSFWorkbook workbook = new SXSSFWorkbook(100);
OutputStream out = response.getOutputStream();
String lastFileName = fileName + ".xlsx";
response.setContentType("application/msexcel;charset=UTF-8");
response.setHeader("Content-Disposition", "attachment; filename="
+ URLEncoder.encode(lastFileName, "UTF-8"));
int k = 0;
int rowIndex;
Sheet sheet = workbook.createSheet(fileName + (k + 1));
//写入excel的表头
Row titleNameRow = workbook.getSheet(fileName + (k + 1)).createRow(0);
for (int i = 0; i < titleName.length; i++) {
sheet.setColumnWidth(i, titleSize[i] * 256); //设置宽度
Cell cell = titleNameRow.createCell(i);
cell.setCellValue(titleName[i]);
}
//写入到excel中
if (dataList != null && dataList.size() > 0) {
if (titleColumn.length > 0) {
for (int index = 0; index < dataList.size(); index++) {
//每个sheet3W条数据
if (index != 0 && (index) % 30000 == 0) {
k = k + 1;
sheet = workbook.createSheet(fileName + (k + 1));
//写入excel的表头
titleNameRow = workbook.getSheet(fileName + (k + 1)).createRow(0);
for (int i = 0; i < titleName.length; i++) {
sheet.setColumnWidth(i, titleSize[i] * 256); //设置宽度
Cell cell = titleNameRow.createCell(i);
cell.setCellValue(titleName[i]);
}
}
if (index < 30000) {
rowIndex = index + 1;
} else {
rowIndex = index - 30000 * ((index) / 30000) + 1;
}
Object obj = dataList.get(index);
Class clazz = obj.getClass();
Row dataRow = workbook.getSheet(fileName + (k + 1)).createRow(rowIndex);
for (int columnIndex = 0; columnIndex < titleColumn.length; columnIndex++) {
String title = titleColumn[columnIndex].trim();
if (!"".equals(title)) {
// 获取返回类型
String UTitle = Character.toUpperCase(title.charAt(0)) + title.substring(1, title.length()); // 使其首字母大写;
String methodName = "get" + UTitle;
Method method = clazz.getDeclaredMethod(methodName);
String returnType = method.getReturnType().getName();
Object object = method.invoke(obj);
String data = method.invoke(obj) == null ? "" : object.toString();
Cell cell = dataRow.createCell(columnIndex);
if (data != null && !"".equals(data)) {
if ("int".equals(returnType)) {
cell.setCellValue(Integer.parseInt(data));
} else if ("long".equals(returnType)) {
cell.setCellValue(Long.parseLong(data));
} else if ("float".equals(returnType)) {
cell.setCellValue(new DecimalFormat("0.00").format(Float.parseFloat(data)));
} else if ("double".equals(returnType)) {
cell.setCellValue(new DecimalFormat("0.00").format(Double.parseDouble(data)));
} else if (Date.class.getName().equals(returnType)) {
cell.setCellValue(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(object));
} else {
cell.setCellValue(data);
}
} else { //字段为空 检查该列是否是公式
if (colFormula != null) {
String sixBuf = colFormula[columnIndex].replace("@", (rowIndex + 1) + "");
cell = dataRow.createCell(columnIndex);
cell.setCellFormula(sixBuf);
}
}
}
}
}
}
}
workbook.write(out);
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 将16进制的颜色代码写入样式中来设置颜色
*
* @param style 保证style统一
* @param color 颜色：66FFDD
* @param index 索引 8-64 使用时不可重复
* @return
*/
public CellStyle setColor(CellStyle style, String color, short index) {
if ("".equals(color)) {
//转为RGB码
int r = Integer.parseInt((color.substring(0, 2)), 16); //转为16进制
int g = Integer.parseInt((color.substring(2, 4)), 16);
int b = Integer.parseInt((color.substring(4, 6)), 16);
//自定义cell颜色
HSSFPalette palette = workbook.getCustomPalette();
palette.setColorAtIndex((short) index, (byte) r, (byte) g, (byte) b);
style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
style.setFillForegroundColor(index);
}
return style;
}
/**
* 设置字体并加外边框
*
* @param style 样式
* @param style 字体名
* @param style 大小
* @return
*/
public CellStyle setFontAndBorder(CellStyle style, String fontName, short size) {
HSSFFont font = workbook.createFont();
font.setFontHeightInPoints(size);
font.setFontName(fontName);
font.setBold(true);
style.setFont(font);
style.setBorderBottom(BorderStyle.THIN); //下边框
style.setBorderLeft(BorderStyle.THIN);//左边框
style.setBorderTop(BorderStyle.THIN);//上边框
style.setBorderRight(BorderStyle.THIN);//右边框
return style;
}
}
调用的例子
/**
* 保有量-导出Excel
*
* @param response
*/
@Override
public void exportInventoryResult(HttpServletResponse response, Map map, Long companyId) {
List<InventoryDto> inventoryDtoList = inventoryMapper.selectExportInventoryResult(map, companyId);
try {
ExcelExport excelExport = new ExcelExport();
excelExport.writeBigExcel(response, "保有量导出数据", new String[]{"materialCode", "materialName", "number", "countryArea"}
, new String[]{"物料号", "物料名称", "数量", "国家大区"}
, new int[]{30, 30, 30, 30}, inventoryDtoList);
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 导出Excel所有
*
* @param response
*/
@Override
public void exportExcel(HttpServletResponse response, Long companyId) {
List<EpcSystemDictionary> epcSystemDictionaryList = epcSystemDictionaryMapper.getAll(companyId);
ExcelExport excelExport = new ExcelExport(response, "数据字典总数据", "sheet1");
excelExport.writeExcel(new String[]{"code", "name", "enName", "level", "sort"}
, new String[]{"编号", "名称", "英文名称", "层级", "排序"}
, new int[]{30, 30, 30, 30, 30}, epcSystemDictionaryList);
}
其实代码没有很复杂，也是比较简单的。我遇到的难点就是分sheet的时候，就这么简单的东西，算了接近两个小时，数学太差了。这一点似乎也没有救了。
