java 写入excel或者在excel中追加数据

一、创建springboot项目，导入依赖

		<dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>easyexcel</artifactId>
            <version>2.1.6</version>
        </dependency>

二、创建实体类（如果有必要）

public class student(){
	private String id;
	private String name;
}

三、创建需要写入的数据

List<Student> stuList(){
	Student student1 = new Student("10000","小明");
	Student student2 = new Student("10001","李华");
	List<Student> list = new ArrayList<>();
	list.add(student1);
	list.add(student2);
	return list;
}

四、写入数据

	String filename = "C:\\Users\\admin\\Desktop\\student.xlsx";//写在哪里的文件
	EasyExcel.write(filename,Student.class).sheet("sheet1").doWrite(stuList());
	//使用这个方法写入，新的数据会把旧的数据覆盖

五、追加数据

import org.apache.poi.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;


	String filename = "C:\\Users\\admin\\Desktop\\port.xlsx";
	FileInputStream fileInputStream = new FileInputStream(filename);
    XSSFWorkbook xssfWorkbook = new XSSFWorkbook(fileInputStream);
    XSSFSheet sheet = xssfWorkbook.getSheetAt(0);
    FileOutputStream fileOutputStream = new FileOutputStream(filename);
    
    for(Studnet value : stuList()){
    	XSSFRow row = sheet.createRow(sheet.getLastRowNum() + 1);//新增一行
        XSSFCell cell1 = row.createCell(0);//行中的第“0+1”列
        cell1.setCellValue(port.getId());//列中放的值
        XSSFCell cell2 = row.createCell(1);
        cell2.setCellValue(port.getName());
    }
    
fileOutputStream.flush();
        xssfWorkbook.write(fileOutputStream);
        fileOutputStream.close();