POI导出简单案例

代码如下：

本文参考自：https://blog.csdn.net/m0_37681532/article/details/75252236

package kklazy.api.controller;

import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.OutputStream;
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.HSSFFont;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFSheet;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;

import kklazy.security.model.User;


public class Excel {
    
    public static void main(String[] args) {
        exportExcel();
    }
    
    public static void   exportExcel(){
        FileOutputStream fos=null;
        try {
            //若文件地址在C盘：抛出异常：java.io.FileNotFoundException: C:bb.xls (拒绝访问。)————>可能原因:C盘权限问题
            fos = new FileOutputStream("D:\bbb.xls");
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
        HSSFWorkbook wb = new HSSFWorkbook();
        HSSFSheet  sheet = wb.createSheet();
        wb.setSheetName(0, "我的工作簿1");//设置名字
        HSSFRow row  = sheet.createRow(0);//创建第一行
        //设置样式
        HSSFCellStyle style = wb.createCellStyle();
        style.setAlignment(HSSFCellStyle.ALIGN_CENTER);//对齐方式
        //设置上下左右边框;
        style.setBorderTop(HSSFCellStyle.BORDER_THIN);
        style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
        style.setBorderLeft(HSSFCellStyle.BORDER_THIN);
        style.setBorderRight(HSSFCellStyle.BORDER_THIN);
        //设置字体样式
        HSSFFont font = wb.createFont();
        font.setFontName("宋体");//设置字体名字
        font.setFontHeightInPoints((short)10);//设置字体大小
        font.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);////设置字体加粗-正常（不加粗）HSSFFont.BOLDWEIGHT_BOLD:加粗
        style.setFont(font);
        //创建单元格,设置样式并赋值
        HSSFCell cell = row.createCell(0);
        cell.setCellStyle(style);
        cell.setCellValue("用户名");
        
        cell = row.createCell(1);
        cell.setCellStyle(style);
        cell.setCellValue("密码");
        List<User> list = new Excel().getUsers();//得到查询数据（模拟数据库查询）
        for(int i=1;i<=list.size();i++){
            row = sheet.createRow(i);
            User user = list.get(i-1);
            cell = row.createCell(0);//创建单元格  先设置样式、编码，然后再置值。
            cell.setCellValue(user.getUsername());

            cell = row.createCell(1);
            cell.setCellValue(user.getPassword());

        }
        
        try {
            wb.write(fos);
            fos.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
        
        
    }
    
    public List<User> getUsers(){
        List<User> users = new ArrayList<User>();
        User u = new User();
        u.setUsername("whh");
        u.setPassword("123456");
        User u1 = new User();
        u1.setUsername("lily");
        u1.setPassword("1234");
        users.add(u);
        users.add(u1);
        return users;
        }
    
    //若要在页面下载,输出流必须通过response获取，并传送到前台下载：
    /*
     * response.setContentType("application/octet-stream;charset=UTF-8");
     * response.setHeader("Content-Disposition",
            "attachment; filename=" + java.net.URLEncoder.encode(reportName+ ".xls", "UTF-8"));
     * OutputStream out = response.getOutputStream();
     * wb.write(out);//写出文件
     * out.flush();
     * out.close();
     * */
}

备注：若要在页面下载,输出流必须通过response获取，并传送到前台下载：

response.setContentType("application/octet-stream;charset=UTF-8");
response.setHeader("Content-Disposition",
 "attachment; filename=" + java.net.URLEncoder.encode(reportName+ ".xls", "UTF-8"));
 OutputStream out = response.getOutputStream();
 wb.write(out);//写出文件
out.flush();
out.close();