poi3.7可以使用HSSFWorkbook导出xls格式，经查数据量只能在65536；
poi3.7可以使用XSSFWorkbook导出xlsx格式，数据量可达到100w，经过跟踪代码发现构建数据起始特别快但当数据量到达5w左右时突然变的很慢，最后报出OutOfMemoryError：java heap space jvm内存溢出错误，调整jvm内存参数无效；
网上搜索得知poi3.8使用SXSSFWorkbook大大优化了大数量的导出，经更换jar包后成功导出！
POI中SXSSFWorkbook专门处理大数据方法：
OutputStream os = null;
try {
HttpServletResponse response = super.getResponse();
response.setContentType("application/force-download"); // 设置下载类型
String filename ="risk_event.xlsx";
response.setHeader("Content-Disposition","attachment;filename=" + filename); // 设置文件的名称
os = response.getOutputStream(); // 输出流
SXSSFWorkbook wb = new SXSSFWorkbook(1000);//内存中保留 1000 条数据，以免内存溢出，其余写入 硬盘
//获得该工作区的第一个sheet
Sheet sheet1 = wb.createSheet("sheet1");
int excelRow = 0;
//标题行
Row titleRow = (Row) sheet1.createRow(excelRow++);
for (int i = 0; i < columnList.size(); i++) {
Cell cell = titleRow.createCell(i);
cell.setCellValue(columnList.get(i));
}
for (int m = 0; m < cycleCount; m++) {
List<List<String>> eventStrList = this.convertPageModelStrList();
if (eventStrList!= null && eventStrList.size() > 0) {
for (int i = 0; i < eventStrList.size(); i++) {
//明细行
Row contentRow = (Row) sheet1.createRow(excelRow++);
List<String> reParam = (List<String>) eventStrList.get(i);
for (int j = 0; j < reParam.size(); j++) {
Cell cell = contentRow.createCell(j);
cell.setCellValue(reParam.get(j));
}
}
}
}
wb.write(os);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (os != null) {
os.close();
}
} catch (IOException e) {
e.printStackTrace();
} // 关闭输出流
}
下面是我在网上查询的关于SXSSFWorkbook构造方法api说明
SXSSFWorkbook构造方法API说明
public SXSSFWorkbook(int rowAccessWindowSize)
* Construct an empty workbook and specify the window for row access.
构造一个空的工作簿并指定对行访问的窗口
* <p>
* When a new node is created via createRow() and the total number
当一个新的节点通过createRow()方法生成,并且未被清除的总的记录数目
* of unflushed records would exceed the specified value, then the
将会超过给定的值时,那么
* row with the lowest index value is flushed and cannot be accessed
索引值最小的那一行将被清除并且再也不能通过getRow()方法访问到了
* via getRow() anymore.
* </p>
* <p>
* A value of -1 indicates unlimited access. In this case all
-1值表示不限制的访问. 在这种情形下,
* records that have not been flushed by a call to flush() are available
所有的未被清除的记录都可以通过调用flush方法来随机访问
* for random access.
* <p>
* <p></p>
* A value of 0 is not allowed because it would flush any newly created row
0值是不允许的,因为它会在还没有指定单元格的情况下清除任何新建的行
* without having a chance to specify any cells.
* </p>