Java使用pio读取/生成 xlsx文件

<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi</artifactId>
    <version>4.1.2</version>
</dependency>
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>4.1.2</version>
</dependency>

package com.example.mydemo.MyUtils.ExcelUtil;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import java.io.FileOutputStream;
import java.util.ArrayList;
import java.util.List;
public class PioUtil {
    //将文件保存在项目的resources/excel目录下
    public  static String PATH = System.getProperty("user.dir") + "\\src\\main\\resources\\excel\\";
    public static void main(String[] args) throws Exception {
        int type=2;
        //测试生成文件
        if(type==1){
            List<List<String>> list=new ArrayList<>();
            for (int i = 0; i < 10; i++) {
                List<String> data=new ArrayList<>();
                for (int j = 0; j < 10; j++) {
                    data.add("第"+i+"行--第"+j+"列");
                }
                list.add(data);
            }
            WriteExcel(list,"统计表");
        }

        //测试读取文件
        if(type==2){
            List<List<String>> list=ReadExcel("统计表");
            for (int i = 0; i < list.size(); i++) {
                List<String> data=list.get(i);
                for (int j = 0; j < data.size(); j++) {
                    System.out.println(data.get(j));
                }
            }
        }

    }

    public static List<List<String>> ReadExcel(String name){
        List<List<String>> list=new ArrayList<>();
        try {
            //1、获取工作簿
            XSSFWorkbook workbook = new XSSFWorkbook(PATH+name+".xlsx");
            //2、获取工作表 默认第一张表
            XSSFSheet sheet = workbook.getSheetAt(0);
            //3、获取行
            for (Row row : sheet) {
                List<String> data=new ArrayList<>();
                //4、获取单元格
                for (Cell cell : row) {
                    //5、获取单元格中的内容
                    String value = cell.getStringCellValue();
                    data.add(value);
                }
                list.add(data);
            }
            //释放资源
            workbook.close();
            System.out.println("文件读取成功");
        }catch (Exception e){
            System.out.println("文件读取失败");
        }
        return list;

    }

    public static void WriteExcel(List<List<String>> list,String name){
        try {
            //1.创建一个工作簿
            Workbook workbook = new XSSFWorkbook();
            //2.创建一个工作表
            Sheet sheet = workbook.createSheet("Sheet1");
            //3.创建一行
            for (int i = 0; i < list.size(); i++) {
                List<String> re=list.get(i);
                Row row = sheet.createRow(i);
                for (int j = 0; j < re.size(); j++) {
                    row.createCell(j).setCellValue(re.get(j));
                }
            }
            //生成一张xlsx表
            FileOutputStream fos = new FileOutputStream(PATH +name+ ".xlsx");
            //输出
            workbook.write(fos);
            //关闭流
            fos.close();
            System.out.println("文件生成完毕");
        }catch (Exception e){
            e.printStackTrace();
            System.out.println("文件生成失败");
        }
    }
}