Excel export large data case, poi export case

Reference address: https://www.cnblogs.com/silenceshining/p/11681924.html

maven:

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

Code:

package com.poi;

import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.VerticalAlignment;

import java.io.FileOutputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * @describe:
 * @date: 2020/9/25
 * @TIME: 23:24
 */
public class ExcelTest {
    public static void main(String[] args) throws IOException {
        testHSSFWorkbook();
    }

    public static void testHSSFWorkbook() throws IOException {
        long start = System.currentTimeMillis();

        HSSFWorkbook workbook = new HSSFWorkbook();//创建excel文件(workbook)
        //创建一个工作表sheet ”测试工作表1“是这个工作表的名称，也可以不写
        HSSFSheet sheet = workbook.createSheet("测试工作表1");
        HSSFRow row = sheet.createRow(0);//创建行 从0开始

        HSSFCellStyle style = workbook.createCellStyle();//设置单元格样式
        //TODO 由于版本问题，新的版本剧中是使用HorizontalAlignment.CENTER水平居中 VerticalAlignment.CENTER垂直居中
        //style.setAlignment(HSSFCellStyle.ALIGN_CENTER);//水平居中
        //style.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);
        style.setAlignment(HorizontalAlignment.CENTER);//水平居中
        style.setVerticalAlignment(VerticalAlignment.CENTER);//垂直居中
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        sheet.setDefaultColumnWidth(40);
        row.setHeightInPoints(25);
        //30个表头
        String[] top = new String[30];

        //设置表头
        for (int i = 0; i < top.length; i++) {
            //sheet.setColumnWidth(i,20*256);//第一列设置为20个字符宽度
            HSSFCell cell = row.createCell(i);//创建行的单元格，从0开始
            cell.setCellValue("表头" + i);//设置单元格内容
            cell.setCellStyle(style);
        }
        System.out.println("准备完表头时间：" + (System.currentTimeMillis() - start));
        for (int i = 0; i < 50000; i++) {
            HSSFRow rowInfo = sheet.createRow(i + 1);
            rowInfo.setHeightInPoints(30);
            for (int j = 0; j < 30; j++) {
                HSSFCell cellInfo = rowInfo.createCell(j);
                cellInfo.setCellValue("列内容为" + j +"----"+format.format(new Date()));
                cellInfo.setCellStyle(style);

            }
        }
        System.out.println("准备完表内容时间：" + (System.currentTimeMillis() - start));
        FileOutputStream out = new FileOutputStream("D:\\test.xlsx");
        workbook.write(out);
        out.close();
        System.out.println("输入完成时间：" + (System.currentTimeMillis() - start));
        System.out.println("finish");
    }
}

Realize the effect: