POI操作Excel时最大行、列数的问题及写大量数据时Java heap space内存溢出解决

如果你从开始菜单中启动excel2007，默认是：
1048576
如果你保存或者打开类型为excel工作簿（.xlsx):
1048576

如果你保存或者打开类型为97-2003工作簿（.xls):
65536

public class MaxRowsTest {public static void main(String[] args) {SXSSFWorkbook wb = new SXSSFWorkbook();Sheet sheet = wb.createSheet();for (int i = 0; i < 1048577; i++) {Row row = sheet.createRow(i);Cell cell = row.createCell(0);cell.setCellValue("我是第:" + i + " 条数据");}File file = new File("C:\\Users\\Administrator\\Desktop" + File.separator + "MaxRows.xlsx");OutputStream os;try {os = new FileOutputStream(file);wb.write(os);} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}

当写入的数据超过最大限制时:

Exception in thread "main" java.lang.IllegalArgumentException: Invalid row number (1048576) outside allowable range (0..1048575)at org.apache.poi.xssf.streaming.SXSSFSheet.createRow(SXSSFSheet.java:92)at com.energyfuture.poitest.MaxRowsTest.main(MaxRowsTest.java:34)

写大量数据时,发生 Java heap space 内存溢出时的解决办法:

是用最新版的poi ，这个问题已经解决了，利用缓存的cell,不创建更多的对象实例，导致heap 回收不了。SXSSFWorkbook关键是这个类的使用Java代码  FileOutputStream out = new FileOutputStream(new File("D://result.xlsx"));            Workbook writeWB = new SXSSFWorkbook(500);          Sheet writeSheet = writeWB.createSheet();            for (int rr = 0; rr < 400000; rr++) {              Row writeRow = writeSheet.createRow(rr);              for (int cc = 0; cc < 10; cc++) {                  writeRow.createCell(cc).setCellValue("测试" + rr + "," + cc);              }          }          writeWB.write(out);