关于poi导出excel三种方式HSSFWorkbook

关于poi导出excel三种方式HSSFWorkbook，SXSSFWorkbook，csv的总结 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 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 dataMap = new HashMap();
List titles = new ArrayList();

  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mapvpd.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”)); //3List varList = new ArrayList();PageData就是个HashMapvarList.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 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 titles = (List) 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 varList = (List) model.get("varList");
  int varCount = varList.size();
  for(int i=0; i

}

}

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 dataMap = service.AssignMiddleExcel(page);
OutputStream outputStream = response.getOutputStream();
String sheetName = “逾期客户表”;
List list = (List)dataMap.get(“titles”);
String[] headers = new String[list.size()];
for(int i = 0;i headers[i]=list.get(i);
}
List dataList = new ArrayList<>();
List varList = new ArrayList();
varList = (List)dataMap.get(“varList”);

    varList.forEach(e ->{
        List