关于poi导出excel方式HSSFWorkbook(xls).XSSFWorkbook(xlsx).SXSSFWorkbook.csv的总结

1.HSSFWorkbook(xls)

import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

/*读取xls文件*/
    public static List<PageData> readExcelByFileForXls(File file, int startrow, int startcol, int sheetnum) {
        List<PageData> varList = new ArrayList<PageData>();
        
        try {
            //File target = new File(filepath, filename);
            //File target = new File(file);
            FileInputStream fi = new FileInputStream(file);
            HSSFWorkbook wb = new HSSFWorkbook(fi);//xslx
            HSSFSheet sheet= wb.getSheetAt(sheetnum); //sheet 从0开始

            int rowNum = sheet.getLastRowNum() + 1;                     //取得最后一行的行号
            
            for (int i = startrow; i < rowNum; i++) {                    //行循环开始
                
                PageData varpd = new PageData();
                HSSFRow row = sheet.getRow(i);                             //行
                int cellNum = row.getLastCellNum();                     //每行的最后一个单元格位置
                
                for (int j = startcol; j < cellNum; j++) {                //列循环开始
                    
                    HSSFCell cell = row.getCell(Short.parseShort(j + ""));
                    String cellValue = null;
                    if (null != cell) {
                        switch (cell.getCellType()) {                     // 判断excel单元格内容的格式，并对其进行转换，以便插入数据库
                        case 0:
                            cellValue = String.valueOf((int) cell.getNumericCellValue());
                            break;
                        case 1:
                            cellValue = cell.getStringCellValue();
                            break;
                        case 2:
                            cellValue = cell.getNumericCellValue() + "";
                            // cellValue = String.valueOf(cell.getDateCellValue());
                            break;
                        case 3:
                            cellValue = "";
                            break;
                        case 4:
                            cellValue = String.valueOf(cell.getBooleanCellValue());
                            break;
                        case 5:
                            cellValue = String.valueOf(cell.getErrorCellValue());
                            break;
                        }
                    } else {
                        cellValue = "";
                    }
                    
                    varpd.put("var"+j, cellValue);
                    
                }
                varList.add(varpd);
            }
            
        } catch (Exception e) {
            System.out.println(e);
        }
        
        return varList;
    }

2.XSSFWorkbook(xlsx)

/*读取xlsx文件*/
    public static List<PageData> readExcelByFileForXlsx(File file, int startrow, int startcol, int sheetnum) {
        List<PageData> varList = new ArrayList<PageData>();        
        try {
            //File target = new File(filepath, filename);
            //File target = new File(file);
            FileInputStream fi = new FileInputStream(file);
            XSSFWorkbook wb = new XSSFWorkbook(fi);//xslx
            XSSFSheet sheet= wb.getSheetAt(sheetnum); //sheet 从0开始
            int rowNum = sheet.getLastRowNum() + 1;                     //取得最后一行的行号
            
            for (int i = startrow; i < rowNum; i++) {                    //行循环开始
                
                PageData varpd = new PageData();
                XSSFRow row = sheet.getRow(i);                             //行
                int cellNum = row.getLastCellNum();                     //每行的最后一个单元格位置
                
                for (int j = startcol; j < cellNum; j++) {                //列循环开始
                    
                    XSSFCell cell = row.getCell(Short.parseShort(j + ""));
                    String cellValue = null;
                    if (null != cell) {
                        switch (cell.getCellType()) {                     // 判断excel单元格内容的格式，并对其进行转换，以便插入数据库
                        case 0:
                            cellValue = String.valueOf((int) cell.getNumericCellValue());
                            break;
                        case 1:
                            cellValue = cell.getStringCellValue();
                            break;
                        case 2:
                            cellValue = cell.getNumericCellValue() + "";
                            // cellValue = String.valueOf(cell.getDateCellValue());
                            break;
                        case 3:
                            cellValue = "";
                            break;
                        case 4:
                            cellValue = String.valueOf(cell.getBooleanCellValue());
                            break;
                        case 5:
                            cellValue = String.valueOf(cell.getErrorCellValue());
                            break;
                        }
                    } else {
                        cellValue = "";
                    }
                    
                    varpd.put("var"+j, cellValue);
                    
                }
                varList.add(varpd);
            }
            
        } catch (Exception e) {
            System.out.println(e);
        }
        
        return varList;
    }

poi导出excel最常用的是第一种方式HSSFWorkbook，不过这种方式数据量大的话会产生内存溢出问题，SXSSFWorkbook是一种大数据量导出格式，csv是另一种excel导出的一种轻快的实现。

先介绍一下这三种格式的特点

1 HSSFWorkbook  excel文件底层是txt实现，我们经常见到的excel都是这种实现的。

2 SXSSFWorkbook  excel文件底层是xml实现，同样的数据量，大约是第一种的1/6-1/4之间

3 csv 这个比较新潮，数据量应该更小，可以百度。

一 HSSFWorkbook 实现

Map<String, Object> dataMap = service.AssignMiddleExcel(page);
ObjectExcelView erv = new ObjectExcelView("逾期客户表");             //执行excel操作
mv = new ModelAndView(erv,dataMap);
dataMap 是个map ,包含两个键值对  一个是标题列 
Map<String,Object> dataMap = new HashMap<String,Object>();
      List<String> titles = new ArrayList<String>();
      
      titles.add("借款人姓名");        //1
      titles.add("身份证号");         //2
      titles.add("借款人手机号");
   dataMap.put("titles", titles);
  这是标题列
vpd是个map
vpd.put("var1", userList.get(i).getString("realName"));     //1
vpd.put("var2", userList.get(i).getString("contIdCard"));   //2
vpd.put("var3", userList.get(i).getString("telephone"));    //3
List<PageData> varList = new ArrayList<PageData>();
PageData就是个HashMap
varList.add(vpd);
dataMap.put("varList", varList);
这就是dataMap的由来

public class ObjectExcelView extends AbstractExcelView{
   
   private String fileName;
   
   public ObjectExcelView(){
      
   }
   public ObjectExcelView(String fileName){
      
      this.fileName = fileName;
   }
   
   @Override
   protected void buildExcelDocument(Map<String, Object> model,
         HSSFWorkbook workbook, HttpServletRequest request,
         HttpServletResponse response) throws Exception {
      // TODO Auto-generated method stub
      //String fileName = "逾期客户表-待催收";
      HSSFSheet sheet;
      HSSFCell cell;
      response.setContentType("application/x-download");//下面三行是关键代码，处理乱码问题  
      response.setCharacterEncoding("utf-8");  
      response.setHeader("Content-Disposition", "attachment;filename="+new String(fileName.getBytes("gbk"), "iso8859-1")+".xls");  
      sheet = workbook.createSheet("sheet1");

      List<String> titles = (List<String>) model.get("titles");
      int len = titles.size();
      HSSFCellStyle headerStyle = workbook.createCellStyle(); //标题样式
      headerStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);
      headerStyle.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);
      HSSFFont headerFont = workbook.createFont();   //标题字体
      headerFont.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
      headerFont.setFontHeightInPoints((short)11);
      headerStyle.setFont(headerFont);
      short width = 20,height=25*20;
      sheet.setDefaultColumnWidth(width);
      for(int i=0; i<len; i++){ //设置标题
         String title = titles.get(i);
         cell = getCell(sheet, 0, i);
         cell.setCellStyle(headerStyle);
         setText(cell,title);
      }
      sheet.getRow(0).setHeight(height);

      HSSFCellStyle contentStyle = workbook.createCellStyle(); //内容样式
      contentStyle.setAlignment(HSSFCellStyle.ALIGN_CENTER);
      List<PageData> varList = (List<PageData>) model.get("varList");
      int varCount = varList.size();
      for(int i=0; i<varCount; i++){
         PageData vpd = varList.get(i);
         for(int j=0;j<len;j++){
            String varstr = vpd.getString("var"+(j+1)) != null ? vpd.getString("var"+(j+1)) : "";
            cell = getCell(sheet, i+1, j);
            cell.setCellStyle(contentStyle);
            setText(cell,varstr);
         }

      }

   }

}

二 SXSSFWorkbook  
@RequestMapping("/excel111")
public Object  exportExcel(Page page,HttpServletRequest request,HttpServletResponse response){
    PageData pd = new PageData();
    pd = this.getPageData();
    try{
        //检索条件===========
        PageData pageData = service.setPdWithTrim(this.getPageData());
        page.setPd(pageData);
        //检索条件===========
        Map<String, Object> dataMap = service.AssignMiddleExcel(page);
        OutputStream outputStream = response.getOutputStream();
        String sheetName = "逾期客户表";
        List<String> list = (List<String>)dataMap.get("titles");
        String[] headers = new  String[list.size()];
        for(int i = 0;i<list.size();i++){
            headers[i]=list.get(i);
        }
        List<Object[]> dataList = new ArrayList<>();
        List<PageData> varList = new ArrayList<PageData>();
        varList =  (List<PageData>)dataMap.get("varList");

        varList.forEach(e ->{
            List<Object> ObjectList =  new ArrayList<>();
            for(int i=0;i<headers.length;i++){
                ObjectList.add(e.get("var"+(i+1))==null?null:e.getString("var"+(i+1)));
            }
           /* for (Object v : e.values()) {
                ObjectList.add(v);
            }*/
            Object[] objarr = new  Object[ObjectList.size()];
            for(int i = 0;i<ObjectList.size();i++){
                objarr[i] = ObjectList.get(i);
            }
            dataList.add(objarr);
        });
        ExportUtil exportUtil = new ExportUtil(sheetName,headers,dataList);
        //SXSSFWorkbook 大批量数据导出
        SXSSFWorkbook workBook =  exportUtil.export();
        // 如果文件名有中文，必须URL编码
        String  fileName1 = URLEncoder.encode(sheetName, "UTF-8");
        // response.reset();
        // response.setContentType("application/force-download");
        response.setContentType("application/vnd.ms-excel");
        response.setHeader("Content-Disposition", "attachment; filename=" + fileName1+".xls");
        workBook.write(outputStream);
        workBook.close();
        outputStream.flush();
        outputStream.close();

        //ObjectExcelView erv = new ObjectExcelView("逾期客户表");           //执行excel操作
        //mv = new ModelAndView(erv,dataMap);
    } catch(Exception e){
        logger.error(e.toString(), e);
    }
    return new Object();
}


package com.fh.controller.assign_out;
import java.util.ArrayList;
import java.util.List;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFFont;
import org.apache.poi.hssf.usermodel.HSSFRichTextString;
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.Font;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.util.CellRangeAddress;
import org.apache.poi.xssf.streaming.SXSSFCell;
import org.apache.poi.xssf.streaming.SXSSFRow;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFCellStyle;
import org.apache.poi.xssf.usermodel.XSSFFont;
import org.springframework.util.StringUtils;
/**
 * Created by dell、 on 2017/10/12.
 */
public class ExportUtil {
    private SXSSFWorkbook wb = null;//大数据导出格式

    private Sheet sheet = null;

    private String sheetName;

    private String[] headers;//表头字段

    private List<Object[]> dataList = new ArrayList<Object[]>();//表内容数据
    //构造
    public ExportUtil(SXSSFWorkbook wb, Sheet sheet) {
        this.wb = wb;
        this.sheet = sheet;
    }
    //构造
    public ExportUtil(String sheetName, String[] headers, List<Object[]> dataList) {
        this.dataList = dataList;
        this.headers = headers;
        this.sheetName = sheetName;
    }
    //不知道做什么
    public void setRegionStyle(CellRangeAddress region, XSSFCellStyle cs) {
        int toprowNum = region.getFirstRow();
        for (int i = toprowNum; i <= region.getLastRow(); i++) {
            SXSSFRow row = (SXSSFRow) sheet.getRow(i);

            for (int j = region.getFirstColumn(); j <= region.getLastColumn(); j++) {
                SXSSFCell cell = (SXSSFCell) row.getCell(j);
                cell.setCellStyle(cs);
            }
        }
    }

    // 设置表头的单元格样式
    public CellStyle getHeadStyle() {
        // 创建单元格样式
        CellStyle cellStyle = wb.createCellStyle();
        // 设置单元格的背景颜色为淡蓝色
        cellStyle.setFillForegroundColor(HSSFColor.PALE_BLUE.index);
        // 设置填充字体的样式
        cellStyle.setFillPattern(XSSFCellStyle.SOLID_FOREGROUND);

        // 设置单元格居中对齐
        cellStyle.setAlignment(XSSFCellStyle.ALIGN_CENTER);

        // 设置单元格垂直居中对齐
        cellStyle.setVerticalAlignment(XSSFCellStyle.VERTICAL_CENTER);

        // 创建单元格内容显示不下时自动换行
        cellStyle.setWrapText(false);

        // 设置单元格字体样式
        XSSFFont font = (XSSFFont) wb.createFont();
        // font.setBoldweight(XSSFFont.BOLDWEIGHT_BOLD);// 这是字体加粗
        font.setFontName("宋体");// 设置字体的样式
        font.setFontHeight(14);// 设置字体的大小
        cellStyle.setFont(font);// 将字体填充到表格中去

        // 设置单元格边框为细线条（上下左右）
        cellStyle.setBorderLeft(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderBottom(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderRight(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderTop(XSSFCellStyle.BORDER_THIN);

        return cellStyle;

    }

    // 设置表体的单元格样式
    public CellStyle getBodyStyle() {
        // 创建单元格样式
        CellStyle cellStyle = wb.createCellStyle();
        // 设置单元格居中对齐
        cellStyle.setAlignment(XSSFCellStyle.ALIGN_CENTER);
        // 设置单元格居中对齐
        cellStyle.setVerticalAlignment(XSSFCellStyle.VERTICAL_CENTER);
        // 创建单元格内容不显示自动换行
        cellStyle.setWrapText(false);
        // 设置单元格字体样式
        XSSFFont font = (XSSFFont) wb.createFont();
        font.setBoldweight(XSSFFont.BOLDWEIGHT_BOLD);// 这是字体加粗
        font.setFontName("宋体");// 设置字体
        font.setFontHeight(12);// 设置字体的大小
        cellStyle.setFont(font);// 将字体添加到表格中去

        // 设置单元格边框为细线条
        cellStyle.setBorderLeft(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderBottom(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderRight(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderTop(XSSFCellStyle.BORDER_THIN);

        return cellStyle;

    }
    //似乎没用到
    public Cell setHeadStyle(String[] titles) {
        Cell cell = null;

        CellStyle headStyle = getHeadStyle();

        Row headRow = sheet.createRow(0);
        // 构建表头
        for (int i = 0; i < titles.length; i++) {
            cell = headRow.createCell(i);
            cell.setCellStyle(headStyle);
            cell.setCellValue(titles[i]);
        }
        return cell;
    }

    /*
    * 导出数据
    */
    public SXSSFWorkbook export() throws Exception {
        // String nsheetName = new String(sheetName.getBytes("UTF-8"));
            /*
            * response.setCharacterEncoding("utf-8");
            * response.setContentType("application/x-msdownload");
            * response.setHeader("Content-disposition", "attachment; filename=" +
            * sheetName + ".xlsx");// 组装附件名称和格式
            */
        Integer rowaccess = 1000;// 内存中缓存记录行数，以免内存溢出

        SXSSFWorkbook workbook = new SXSSFWorkbook(rowaccess);
        try {

            Sheet sheet = workbook.createSheet(sheetName);

            // 产生表格标题行
            Row titleRow = sheet.createRow(0);
            Cell cellTiltle = titleRow.createCell(0);
            CellStyle columnTopStyle = this.getColumnTopStyle(workbook);// 获取列头样式对象
            sheet.setDefaultColumnWidth(100);
            sheet.addMergedRegion(new CellRangeAddress(0, 1, 0, (headers.length - 1)));
            cellTiltle.setCellStyle(columnTopStyle);
            cellTiltle.setCellValue(sheetName);

            Cell cell = null;

            CellStyle headStyle = this.getHeadStyle(workbook);

            // 定义所需列数
            int columnNum = headers.length;
            Row headRow = sheet.createRow(2); // 在索引2的位置创建行(最顶端的行开始的第二行)

            //表头
            for (int n = 0; n < columnNum; n++) {
                Cell cellRowName = headRow.createCell(n); // 创建列头对应个数的单元格
                cellRowName.setCellType(HSSFCell.CELL_TYPE_STRING); // 设置列头单元格的数据类型
                HSSFRichTextString text = new HSSFRichTextString(headers[n]);
                cellRowName.setCellValue(headers[n]); // 设置列头单元格的值
                cellRowName.setCellStyle(headStyle); // 设置列头单元格样式
                sheet.setColumnWidth(n,256*20);
            }

            CellStyle bodyStyle = this.getBodyStyle(workbook);

            // 表体数据
            for (int i = 0; i < dataList.size(); i++) {

                Object[] obj = dataList.get(i);
                Row row = sheet.createRow(i + 3);// 创建所需的行数

                for (int j = 0; j < obj.length; j++) {

                    cell = row.createCell(j);
                    String str = String.valueOf(StringUtils.isEmpty(obj[j]) ? "" : obj[j]);
                    cell.setCellValue(str); // 单元格的值
                    cell.setCellStyle(bodyStyle); // 单元格的样式
                }
            }


        } catch (Exception e) {
            e.printStackTrace();
        }

        return workbook;
    }

    // 设置表头的单元格样式
    public CellStyle getHeadStyle(SXSSFWorkbook workbook) {
        // 创建单元格样式
        CellStyle cellStyle = workbook.createCellStyle();

        // 设置单元格的背景颜色为淡蓝色
        cellStyle.setFillForegroundColor(HSSFColor.PALE_BLUE.index);
        // 设置填充字体的样式
        cellStyle.setFillPattern(XSSFCellStyle.SOLID_FOREGROUND);

        // 设置单元格居中对齐
        cellStyle.setAlignment(XSSFCellStyle.ALIGN_CENTER);

        // 设置单元格垂直居中对齐
        cellStyle.setVerticalAlignment(XSSFCellStyle.VERTICAL_CENTER);
        // cellStyle.setShrinkToFit(true);
        // 创建单元格内容显示不下时自动换行
        //cellStyle.setWrapText(true);

        // 设置单元格字体样式
        XSSFFont font = (XSSFFont) workbook.createFont();
        //  font.setBoldweight(XSSFFont.BOLDWEIGHT_BOLD);// 这是字体加粗
        font.setFontName("宋体");// 设置字体的样式
        font.setFontHeight(12);// 设置字体的大小
        cellStyle.setFont(font);// 将字体填充到表格中去

        // 设置单元格边框为细线条（上下左右）
        cellStyle.setBorderLeft(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderBottom(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderRight(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderTop(XSSFCellStyle.BORDER_THIN);

        return cellStyle;

    }

    // 设置表体的单元格样式
    public CellStyle getBodyStyle(SXSSFWorkbook workbook) {
        // 创建单元格样式
        CellStyle cellStyle = workbook.createCellStyle();
        // 设置单元格居中对齐
        cellStyle.setAlignment(XSSFCellStyle.ALIGN_CENTER);
        // 设置单元格居中对齐
        cellStyle.setVerticalAlignment(XSSFCellStyle.VERTICAL_CENTER);
        // 创建单元格内容不显示自动换行
        //cellStyle.setWrapText(true);
        // 设置单元格字体样式
        XSSFFont font = (XSSFFont) workbook.createFont();
        //   font.setBoldweight(XSSFFont.BOLDWEIGHT_BOLD);// 这是字体加粗
        font.setFontName("宋体");// 设置字体
        font.setFontHeight(10);// 设置字体的大小
        cellStyle.setFont(font);// 将字体添加到表格中去

        // 设置单元格边框为细线条
        cellStyle.setBorderLeft(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderBottom(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderRight(XSSFCellStyle.BORDER_THIN);
        cellStyle.setBorderTop(XSSFCellStyle.BORDER_THIN);

        return cellStyle;

    }

    public Cell setHeadStyle(String[] titles, SXSSFWorkbook workbook) {
        Cell cell = null;

        CellStyle headStyle = getHeadStyle(workbook);

        Row headRow = sheet.createRow(0);
        // 构建表头
        for (int i = 0; i < titles.length; i++) {
            cell = headRow.createCell(i);
            cell.setCellStyle(headStyle);
            cell.setCellValue(titles[i]);
        }
        return cell;
    }

    /*
    * 列头单元格样式
    */
    public CellStyle getColumnTopStyle(SXSSFWorkbook workbook) {

        // 设置字体
        Font font = workbook.createFont();
        // 设置字体大小
        font.setFontHeightInPoints((short) 18);
        // 字体加粗
        font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
        // 设置字体名字
        font.setFontName("Courier New");
        // 设置样式;
        CellStyle style = workbook.createCellStyle();
        // 设置底边框;
        style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
        // 设置底边框颜色;
        style.setBottomBorderColor(HSSFColor.BLACK.index);
        // 设置左边框;
        style.setBorderLeft(HSSFCellStyle.BORDER_THIN);
        // 设置左边框颜色;
        style.setLeftBorderColor(HSSFColor.BLACK.index);
        // 设置右边框;
        style.setBorderRight(HSSFCellStyle.BORDER_THIN);
        // 设置右边框颜色;
        style.setRightBorderColor(HSSFColor.BLACK.index);
        // 设置顶边框;
        style.setBorderTop(HSSFCellStyle.BORDER_THIN);
        // 设置顶边框颜色;
        style.setTopBorderColor(HSSFColor.BLACK.index);
        // 在样式用应用设置的字体;
        style.setFont(font);
        // 设置自动换行;
        style.setWrapText(false);
        // 设置水平对齐的样式为居中对齐;
        style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
        // 设置垂直对齐的样式为居中对齐;
        style.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);

        return style;

    }
}

三 csv
/*
* 导出委外催收中EXCEL 大数据量csv导出
* @return
*/
@RequestMapping("/excel")
public  Object  exportExcel111(Page page, HttpServletResponse response ) {
    PageData pd = new PageData();
    pd = this.getPageData();
    try {
        //检索条件===========
        PageData pageData = service.setPdWithTrim(this.getPageData());
        page.setPd(pageData);
        //检索条件===========
        Map<String, Object> dataMap = service.AssignMiddleExcel(page);
        String sheetName = "逾期客户表";
        List<Object> headlist = (List<Object>)dataMap.get("titles");
        List<List<Object>> dataList = new ArrayList<>();
        List<PageData> varList = new ArrayList<PageData>();
        varList =  (List<PageData>)dataMap.get("varList");

        varList.forEach(e ->{
            List<Object> ObjectList =  new ArrayList<>();
            for(int i=0;i<headlist.size();i++){
                ObjectList.add(e.get("var"+(i+1))==null?null:e.getString("var"+(i+1)));
            }
            dataList.add(ObjectList);
        });
        File csvFile =CSVUtils.createCSVFile(headlist,dataList,sheetName);
        BufferedInputStream bis = null;
        BufferedOutputStream bos = null;

        response.setHeader("Content-disposition", "attachment; filename=" + URLEncoder.encode(csvFile.getName(), "UTF-8"));

        response.setHeader("Content-Length", String.valueOf(csvFile.length()));

        bis = new BufferedInputStream(new FileInputStream(csvFile));
        bos = new BufferedOutputStream(response.getOutputStream());
        byte[] buff = new byte[2048];
        while (true) {
            int bytesRead;
            if (-1 == (bytesRead = bis.read(buff, 0, buff.length))) break;
            bos.write(buff, 0, bytesRead);
        }
        bis.close();
        bos.close();
        csvFile.delete();
    }catch (Exception e){
        e.printStackTrace();
    }
    return new Object();
}
package com.fh.controller.assign_out;

import javax.servlet.http.HttpServletRequest;
import java.io.*;
import java.util.*;

/**
 * Created by dell、 on 2017/10/12.
 */
public class CSVUtils {
    /**
     * CSV文件生成方法
     * @param head
     * @param dataList
     * @param filename
     * @return
     */
    public static File createCSVFile(List<Object> head, List<List<Object>> dataList,
                                      String filename) {

        File csvFile = null;
        BufferedWriter csvWtriter = null;
        try {
            csvFile = new File( "temp123/"+ File.separator + filename + ".csv");
            File parent = csvFile.getParentFile();
            if (parent != null && !parent.exists()) {
                parent.mkdirs();
            }
            csvFile.createNewFile();

            // GB2312使正确读取分隔符","
            csvWtriter = new BufferedWriter(new OutputStreamWriter(new FileOutputStream(
                    csvFile), "GB2312"), 1024);
            // 写入文件头部
            writeRow(head, csvWtriter);

            // 写入文件内容
            for (List<Object> row : dataList) {
                writeRow(row, csvWtriter);
            }
            csvWtriter.flush();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                csvWtriter.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return csvFile;
    }

    /**
     * 写一行数据方法
     * @param row
     * @param csvWriter
     * @throws IOException
     */
    private static void writeRow(List<Object> row, BufferedWriter csvWriter) throws IOException {
        // 写入文件头部
        for (Object data : row) {
            StringBuffer sb = new StringBuffer();
            String rowStr = sb.append(""").append(data).append("",").toString();
            csvWriter.write(rowStr);
        }
        csvWriter.newLine();
    }
    public static File createCSVFile(HttpServletRequest request){
        List< Map<String,Object>> list = new ArrayList<>();
        for(int i =0;i<10;i++){
           Map<String,Object> mao = new HashMap<>();
           mao.put("cutomerName","zhangsan"+i);
           mao.put("cutomerNam1","zhangsan"+i);
           mao.put("cutomerNam2","zhangsan"+i);
           mao.put("cutomerNam3","zhangsan"+i);
           mao.put("cutomerNam4","zhangsan"+i);
           mao.put("cutomerNam5","zhangsan"+i);
           mao.put("cutomerNam6","zhangsan"+i);
           mao.put("cutomerNam7","zhangsan"+i);
           mao.put("cutomerNam8","zhangsan"+i);
           mao.put("cutomerNam9", "2017-10-17 22:33:33 12.00");
           mao.put("cutomerNam10",555555556);
         /*  mao.put("cutomerNam11","zhangsan"+i);
           mao.put("cutomerNam12","zhangsan"+i);
           mao.put("cutomerNam13","zhangsan"+i);
           mao.put("cutomerNam14","zhangsan"+i);
           mao.put("cutomerNam15","zhangsan"+i);
           mao.put("cutomerNam16","zhangsan"+i);
           mao.put("cutomerNam17","zhangsan"+i);
           mao.put("cutomerNam18","zhangsan"+i);
           mao.put("cutomerNam19","zhangsan"+i);
           mao.put("cutomerNam20","zhangsan"+i);
           mao.put("cutomerNam21","zhangsan"+i);
           mao.put("cutomerNam22","zhangsan"+i);
           mao.put("cutomerNam23","zhangsan"+i);
           mao.put("cutomerNam24","zhangsan"+i);
           mao.put("cutomerNam25","zhangsan"+i);
           mao.put("cutomerNam26","zhangsan"+i);
           mao.put("cutomerNam27","zhangsan"+i);
           mao.put("cutomerNam28","zhangsan"+i);
           mao.put("cutomerNam29","zhangsan"+i);
           mao.put("cutomerNam30","zhangsan"+i);
           mao.put("cutomerNam31","zhangsan"+i);
           mao.put("cutomerNam32","zhangsan"+i);
           mao.put("cutomerNam33","zhangsan"+i);
           mao.put("cutomerNam34","zhangsan"+i);
           mao.put("cutomerNam35","zhangsan"+i);
           mao.put("cutomerNam36","zhangsan"+i);
           mao.put("cutomerNam37","zhangsan"+i);
           mao.put("cutomerNam38","zhangsan"+i);
           mao.put("cutomerNam39","zhangsan"+i);
           mao.put("cutomerNam40","zhangsan"+i);
           mao.put("cutomerNam41","zhangsan"+i);
           mao.put("cutomerNam42","zhangsan"+i);
           mao.put("cutomerNam43","zhangsan"+i);
           mao.put("cutomerNam44","zhangsan"+i);
           mao.put("cutomerNam45","zhangsan"+i);*/
            list.add(mao);
       }


        // 设置表格头
        Object[] head = {"客户姓名", "证件类型", "证件号码", "银行账号", "理财账号", "客户类型", "风险等级", "归属状况", "归属机构", "客户经理", "营销比例(%)" };
        List<Object> headList = Arrays.asList(head);
        // 设置数据
        List<List<Object>> dataList = new ArrayList<List<Object>>();
        List<Object> rowList = null;
        for (int i = 0; i < list.size(); i++) {
            rowList = new ArrayList<Object>();
            Map<String,Object>  maovo = list.get(i);
            rowList.add(maovo.get("cutomerName"));
            rowList.add(maovo.get("cutomerNam1"));
            rowList.add(maovo.get("cutomerNam2"));
            rowList.add(maovo.get("cutomerNam3"));
            rowList.add(maovo.get("cutomerNam4"));
            rowList.add(maovo.get("cutomerNam5"));
            rowList.add(maovo.get("cutomerNam6"));
            rowList.add(maovo.get("cutomerNam7"));
            rowList.add(maovo.get("cutomerNam8"));
            rowList.add(maovo.get("cutomerNam9"));
            rowList.add(maovo.get("cutomerNam10"));
            dataList.add(rowList);
        }
        // 导出文件路径
      //  String downloadFilePath = request.getContextPath();
        // 导出文件名称
        String fileName = "客户列表_";
        // 导出CSV文件
        File csvFile = CSVUtils.createCSVFile(headList, dataList, fileName);
        return csvFile;
    }
}