POI 導出大批量數據的Excel

POI作為操作Excel的三方庫應用廣泛，本文着重討論導出大批量數據的Excel的處理，版本為4.1.0：

        <dependency>
            <groupId>org.apache.poi</groupId>
            <artifactId>poi</artifactId>
            <version>4.1.0</version>
        </dependency>

使用HSSFWorkbook進行導出，示例代碼如下，代碼中導出5萬行20列的數據，相應時間見打印的情況：

package com.test.poi;

import java.io.FileOutputStream;
import java.io.IOException;

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;

public class Demo {

    public static void main(String[] args) throws IOException {
        testHSSFWorkbook();
    }

    static void testHSSFWorkbook() throws IOException {
        long start = System.currentTimeMillis();
        HSSFWorkbook workbook = new HSSFWorkbook();
        HSSFSheet sheet = workbook.createSheet();
        HSSFRow row = sheet.createRow(0);
        for (int i = 0; i < 20; i++) {
            HSSFCell cell = row.createCell(i);
            cell.setCellValue("列" + i);
        }
        System.out.println("准備完表頭時間：" + (System.currentTimeMillis() - start));
        for (int i = 0; i < 50000; i++) {
            HSSFRow rowInfo = sheet.createRow(i + 1);
            for (int j = 0; j < 20; j++) {
                HSSFCell cellInfo = rowInfo.createCell(j);
                cellInfo.setCellValue("列內容為" + j);
            }
        }
        System.out.println("准備完表內容時間：" + (System.currentTimeMillis() - start));
        FileOutputStream out = new FileOutputStream("D:\\test.xlsx");
        workbook.write(out);
        out.close();
        System.out.println("輸入完成時間：" + (System.currentTimeMillis() - start));
        System.out.println("finish");
    }

}

輸出結果為：

准備完表頭時間：220
准備完表內容時間：1730
輸入完成時間：4471
finish