大量数据导出

问题

如果数据量较大，那么使用 Apache POI 导出数据可能会导致OOM或者到处时间较长。

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解决方案

使用多线程同时导出多个excel，缩短接口响应时间

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代码示例

public void test () {List<Test> tests = testMapper.selectAll(); // 查询数据// 每个excel 5w 条数据int num = 50000;int size = tests.size();int yushu = size % num;int zhengshu = size / num;if (yushu != 0) {zhengshu++;}// 创建线程池ThreadPoolExecutor threadPool = new ThreadPoolExecutor(5,5,10,TimeUnit.SECONDS,new LinkedBlockingQueue<>(zhengshu),new ThreadPoolExecutor.AbortPolicy());CountDownLatch latch = new CountDownLatch(zhengshu);// 向线程池提交任务for (int i = 0; i < zhengshu; i++) {int finalSheetnum = i;threadPool.execute(() -> {try {// 导出XSSFWorkbook wb = new XSSFWorkbook();XSSFSheet sheet = wb.createSheet("数据：" + finalSheetnum);for (int j = 0; j < num; j++) {XSSFRow row = sheet.createRow(j);int index = finalSheetnum * num + j;if (index < size) {// 填充数据Test test = tests.get(index);XSSFCell cell0 = row.createCell(0);cell0.setCellValue(test.getId());XSSFCell cell1 = row.createCell(1);cell1.setCellValue(test.getName());XSSFCell cell2 = row.createCell(2);cell2.setCellValue(test.getEmail());XSSFCell cell3 = row.createCell(3);cell3.setCellValue(test.getPhone());XSSFCell cell4 = row.createCell(4);cell4.setCellValue(test.getGender());XSSFCell cell5 = row.createCell(5);cell5.setCellValue(test.getPassword());XSSFCell cell6 = row.createCell(6);cell6.setCellValue(test.getAge());XSSFCell cell7 = row.createCell(7);cell7.setCellValue(test.getCreateTime());XSSFCell cell8 = row.createCell(8);cell8.setCellValue(test.getUpdateTime());}}FileOutputStream fileOutputStream = new FileOutputStream("D:/桌面/测试/test" + finalSheetnum + ".xlsx");wb.write(fileOutputStream);fileOutputStream.close();wb.close();System.out.println("File test" + finalSheetnum + ".xlsx has been created.");latch.countDown();} catch (Exception e) {e.printStackTrace();}});}try {latch.await();} catch (InterruptedException e) {e.printStackTrace();}threadPool.shutdown();System.out.println("All threadPool have been closed.");
}

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测试结果