package com.mi.entity;import java.util.Date;public class Student {    private int id;    private String name;    private int age;    private Date birth;        public Student(int id, String name, int age, Date birth) {        super();        this.id = id;        this.name = name;        this.age = age;        this.birth = birth;    }}

package com.mi.util;import java.io.File;import java.io.FileOutputStream;import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.List;import org.apache.poi.hssf.usermodel.HSSFCell;import org.apache.poi.hssf.usermodel.HSSFCellStyle;import org.apache.poi.hssf.usermodel.HSSFRow;import org.apache.poi.hssf.usermodel.HSSFSheet;import org.apache.poi.hssf.usermodel.HSSFWorkbook;import com.mi.entity.Student;public class CreateSimpleExcelToDisk {    /**     * 手工创建一个包含student的list     * @return     * @throws Exception     */    private static List<Student> getStudent() throws Exception {        List<Student> list = new ArrayList<>();        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-mm-dd");        Student user1 = new Student(1, "张三", 16, sdf.parse("1997-03-12"));        Student user2 = new Student(2, "李四", 17, sdf.parse("1996-08-12"));        Student user3 = new Student(3, "王五", 26, sdf.parse("1985-11-12"));        list.add(user1);        list.add(user2);        list.add(user3);                return list;    }    public static void main(String[] args) throws Exception {        //第一步,创建一个webbook文件,对应一个excel文件        HSSFWorkbook wb = new HSSFWorkbook();        //第二部,在excel中添加一个sheet工作簿,参数为该工作簿名字,不写为默认;        HSSFSheet sheet = wb.createSheet("学生表1");        //第三部,做sheet中添加表头第0行,注意老版本poi对excel的行数列数有限制short        HSSFRow row = sheet.createRow((int)0);        //第四部,创建单元格表头 设置表头居中        HSSFCellStyle style = wb.createCellStyle();        style.setAlignment(HSSFCellStyle.ALIGN_CENTER);//创建一个居中格式                //创建具体盛放数据的单元格,可以考虑把cell抽成共通对象去使用        HSSFCell cell = row.createCell((int) 0);        cell.setCellValue("学号");        cell = row.createCell((int) 1);        cell.setCellValue("姓名");        cell = row.createCell((int) 2);        cell.setCellValue("年龄");        cell = row.createCell((int) 3);        cell.setCellValue("生日");                //第五部,写入实体数据 实际应用中这些数据应该是从数据库中得到        List<Student> list = CreateSimpleExcelToDisk.getStudent();        for(int i=0;i<list.size();i++){            //每次新建一行然后在新行中插入list中的数据对象,有点繁琐,也许有更好的封装方法,留待后看            row = sheet.createRow((int)i+1);            row.createCell((int)0).setCellValue(list.get(i).getId());            row.createCell((int)1).setCellValue(list.get(i).getName());            row.createCell((int)2).setCellValue(list.get(i).getAge());            row.createCell((int)3).setCellValue(new SimpleDateFormat("yyyy-mm-dd").format(list.get(i).getBirth()));                    }                //第六部,将文件保存到指定位置        FileOutputStream fout = new FileOutputStream("D:/student.xls");        wb.write(fout);        fout.close();    }}