springboot poi导出Excel

什么是poi？

poi是阿帕奇组件开源的poi项目，以基于Office Open XML标准（OOXML）和Microsoft的OLE 2复合文档格式（OLE2）来处理各种文件格式。Apache POI api的主要用途是用于文本提取应用程序，例如网络蜘蛛，索引构建器和内容管理系统。下面我们就来从mysql中导出一个Excel。

第一步：创建数据库和表并且插入数据

第二步:导入maven依赖

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

        <!--mysql-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.21</version>
        </dependency>

因为Excle有03版和07版，也就是xls和xlsx这两个版本所以我们分别导入各自的poi依赖。

第三步:把需要导出到Excel的表返回List集合

总体结构

pojo

package com.example.demo.pojo;

public class Student {

    private int id;

    private String name;

    private int age;

    private String phone;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String getPhone() {
        return phone;
    }

    public void setPhone(String phone) {
        this.phone = phone;
    }
}

dao

package com.example.demo.dao;

import com.example.demo.pojo.Student;
import org.apache.ibatis.annotations.Mapper;
import java.util.List;
@Mapper
public interface StudentMapper {

    List<Student> findAll();
}

*.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.example.demo.dao.StudentMapper">
    <select id="findAll" resultType="com.example.demo.pojo.Student">
        SELECT * FROM student
    </select>
</mapper>

service

package com.example.demo.service;

import com.example.demo.pojo.Student;

        import java.util.List;

public interface StudentService {
    List<Student> findAll();
}

Impl

package com.example.demo.service.Impl;

import com.example.demo.dao.StudentMapper;
import com.example.demo.pojo.Student;
import com.example.demo.service.StudentService;
import org.springframework.stereotype.Service;
import javax.annotation.Resource;
import java.util.List;

@Service
public class StudentServiceImpl implements StudentService{

    @Resource
    private StudentMapper studentMapper;

    @Override
    public List<Student> findAll() {
        return studentMapper.findAll();
    }
}

util

package com.example.demo.util;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.*;

public class ExcelUtil {
    public static void createFile(HttpServletResponse response, HSSFWorkbook workbook) {

        //设置文件名
        String fileName = "学生信息";

        try {
            //捕获内存缓冲区的数据，装换成字符数组
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            workbook.write(out);
            // 获取内存缓冲中的数据
            byte[] content = out.toByteArray();
            // 将字节数组转化为输入流
            InputStream in = new ByteArrayInputStream(content);
            //通过调用reset（）方法可以重新定位。
            response.reset();
            // 如果文件名是英文名不需要加编码格式，如果是中文名需要添加"iso-8859-1"防止乱码
            response.setHeader("Content-Disposition", "attachment; filename=" + new String((fileName + ".xls").getBytes(), "iso-8859-1"));
            response.addHeader("Content-Length", "" + content.length);
            response.setContentType("application/vnd.ms-excel;charset=UTF-8");
            ServletOutputStream outputStream = response.getOutputStream();
            BufferedInputStream bis = new BufferedInputStream(in);
            BufferedOutputStream bos = new BufferedOutputStream(outputStream);
            byte[] buff = new byte[8192];
            int bytesRead;
            while (-1 != (bytesRead = bis.read(buff, 0, buff.length))) {
                bos.write(buff, 0, bytesRead);
            }
            bis.close();
            bos.close();
            outputStream.flush();
            outputStream.close();
        } catch (IOException e) {
            e.printStackTrace();
        }

    }
}

controller

package com.example.demo.controller;

import com.example.demo.pojo.Student;
import com.example.demo.service.StudentService;
import com.example.demo.util.ExcelUtil;
import org.apache.poi.hssf.usermodel.*;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.util.List;

@Controller
public class StudentController {

    @Resource
    private StudentService studentService;
    
    @RequestMapping("/exportExcle")
    public void exportExcle(HttpServletRequest request, HttpServletResponse response){
        List<Student> list=studentService.findAll();
        //创建工作薄
        HSSFWorkbook workbook=new HSSFWorkbook();
        //创建表
        HSSFSheet sheet=workbook.createSheet("学生信息");
        //创建行
        HSSFRow row=sheet.createRow(0);
        //创建单元格式
        HSSFCellStyle cellStyle=workbook.createCellStyle();
        //表头
        String[] head={"序号","姓名","年龄","手机号码"};
        HSSFCell cell;
        //设置表头
        for(int iHead=0;iHead<head.length;iHead++){
             cell=row.createCell(iHead);
             cell.setCellValue(head[iHead]);
             cell.setCellStyle(cellStyle);
        }

        //设置表格内容
        for (int iBody=0;iBody<list.size();iBody++){
            row=sheet.createRow(iBody+1);
            Student student=list.get(iBody);
            String[] studentArray =new String[4];
            studentArray[0]= String.valueOf(student.getId());
            studentArray[1]=student.getName()+ "";
            studentArray[2]=student.getAge() + "";
            studentArray[3]=student.getPhone()+ "";
            for(int iArray=0; iArray<studentArray.length; iArray++) {
                row.createCell(iArray).setCellValue(studentArray[iArray]);
            }

        }
        // 生成Excel文件
        ExcelUtil.createFile(response, workbook);
    }
}

导出Excel效果图

启动项目之后，在浏览器输入http://localhost:8080/exportExcel就可以进入，帮你导出Excel

然后打开Excel查看

这样就完成了Excel的导出，需要深入了解可以前往官网地址