转：POI操作Excel导出

package com.rd.lh.util.excel;

import java.beans.PropertyDescriptor;
import java.io.FileOutputStream;
import java.io.IOException;
import java.math.BigDecimal;
import java.net.URLEncoder;
import java.sql.Timestamp;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.beanutils.PropertyUtilsBean;
import org.apache.poi.ss.usermodel.BorderStyle;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Font;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
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.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFRichTextString;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.rd.ifaes.common.util.BigDecimalUtils;
import com.rd.ifaes.common.util.DateUtils;
import com.rd.ifaes.common.util.StringUtils;

/**
 * excel 导出工具类
 * @author lh
 * @version 3.0
 * @since 2016-11-8
 *
 */
public class ExportUtil {

    private static final Logger LOGGER = LoggerFactory.getLogger(ExportUtil.class);

    private static final int sheetMaxCount = 1000000;//单个sheet最多写入行数

    public static <T> void exportExcel(String title, String[] headers, String[] fields, int startRow, Workbook wb, List<T> data) throws IOException {

        Sheet sheet = null;
        startRow = startRow>0?startRow+2:startRow;
        int index = startRow, pageRowNo = startRow, columnCount = headers.length; // 行号、页码、列数

        for (T obj : data) {
            int sheetIndex = index/sheetMaxCount;
            if (index % sheetMaxCount == 0) {
                sheet = wb.createSheet(title + "_" + (sheetIndex + 1));
                sheet = wb.getSheetAt(sheetIndex);
                sheet.setDisplayGridlines(false);// 设置表标题是否有表格边框
                pageRowNo = 2;
                createHeader(sheet, title, headers);
            }else{
                sheet = wb.getSheetAt(sheetIndex);
            }
            index++;
            @SuppressWarnings("unchecked")
            Map<String, Object> map = obj instanceof Map ? (Map<String, Object>) obj : beanToMap(obj);
            Row nRow = sheet.createRow(pageRowNo++); // 新建行对象
            for (int j = 0; j < columnCount; j++) {
                Cell cell = nRow.createCell(j);
                setCellValue(sheet, cell, map.get(fields[j]));
            }
        }

    }

    /**
     * write Workbook
     * @param wb
     * @param filePath
     * @throws IOException
     */
    public static void writeWorkbook(Workbook wb, String filePath)throws IOException{
        FileOutputStream fos = new FileOutputStream(filePath + "/workbook.xlsx");
        wb.write(fos);
        fos.flush();
        fos.close();
        wb.close();
    }

    /**
     * responseWorkbook
     * @param title
     * @param wb
     * @param request
     * @param response
     * @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");
        wb.write(response.getOutputStream());
    }
    /**
     * 设置单元格的值
     * @param cell
     * @param cellVal
     */
    public static void setCellValue(Sheet sheet, Cell cell, Object cellVal){
        if(cellVal == null || String.class.equals(cellVal.getClass())){
            cell.setCellValue(StringUtils.isNull(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(BigDecimalUtils.round(cellVal.toString()).doubleValue());
        }else if(Date.class.equals(cellVal.getClass())){
            cell.setCellValue(DateUtils.formatDateTime((Date)cellVal));
        }else if(Timestamp.class.equals(cellVal.getClass())){
            cell.setCellValue(DateUtils.formatDateTime((Timestamp)cellVal));
        }else{
            cell.setCellValue(StringUtils.isNull(cellVal));
        }
        cell.setCellStyle(sheet.getWorkbook().getCellStyleAt(3));
    }

    /**
     * JavaBean转Map
     *
     * @param obj
     * @return
     */
    public static Map<String, Object> beanToMap(Object obj) {
        Map<String, Object> 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) {
            LOGGER.error("URLDecoder fail :", e);
        }
        return params;
    }

    /**
     * 创建表头
     * @param sheet
     * @param headers
     */
    private static void createHeader(Sheet sheet, String title, String[] headers){

        //设置标题
        Row tRow = sheet.createRow(0);
        Cell hc = tRow.createCell(0);
        hc.setCellValue(new XSSFRichTextString(title));
        sheet.addMergedRegion(new CellRangeAddress(0, 0, 0, headers.length - 1));// 合并标题行：起始行号，终止行号， 起始列号，终止列号
        hc.setCellStyle(sheet.getWorkbook().getCellStyleAt(1));

        //设置表头
        Row nRow = sheet.createRow(1);
        for (int i = 0; i < headers.length; i++) {
            Cell cell =    nRow.createCell(i);
            cell.setCellValue(headers[i]);
            cell.setCellStyle(sheet.getWorkbook().getCellStyleAt(2));
        }
    }

    /**
     * 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");
        hfont.setFontHeightInPoints((short) 16);// 设置字体大小
        hfont.setBold(true);// 加粗
        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");
        tfont.setFontHeightInPoints((short) 12);// 设置字体大小
        tfont.setBold(true);// 加粗
        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");
        font.setFontHeightInPoints((short) 12);// 设置字体大小

        return wb;
    }

}

转自：http://hbxflihua.iteye.com/blog/2336173