pom.xml 添加Apache POL依赖

<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi</artifactId>
<version>3.14</version>
</dependency>

导出excel

导出excel比较重要的api有以下几个，其他的并无难点

• 创建一个excel文件工作薄；（HSSFWorkbook workbook = new HSSFWorkbook()）
• 创建一张表；HSSFSheet sheet = workbook.createSheet("统计表")
• 创建一行；HSSFRow row = sheet.createRow(0)
• 填充一列数据; row.createCell(0).setCellValue("数据")
• 设置一个单元格样式；cell.setCellStyle(style)
  package com.spring.jianyue.api.controller;

import com.spring.jianyue.api.entity.User;
import com.spring.jianyue.api.entity.vo.ArticleVO;
import com.spring.jianyue.api.service.ArticleService;
import com.spring.jianyue.api.service.UserService;
import org.apache.poi.hssf.usermodel.*;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import javax.servlet.http.HttpServletResponse;
import java.io.FileOutputStream;
import java.io.OutputStream;
import java.net.URLEncoder;
import java.util.List;

@RestController
@RequestMapping(value = "/api/excel")
public class ExcelController {

@Autowired
private ArticleService articleService;

//创建表头
private void createTitle(HSSFWorkbook workbook, HSSFSheet sheet){
    HSSFRow row = sheet.createRow(0);
    //设置列宽，setColumnWidth的第二个参数要乘以256，这个参数的单位是1/256个字符宽度
    sheet.setColumnWidth(1,12*256);
    sheet.setColumnWidth(3,17*256);

    //设置为居中加粗
    HSSFCellStyle style = workbook.createCellStyle();
    HSSFFont font = workbook.createFont();
    font.setBold(true);
    style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
    style.setFont(font);

    HSSFCell cell;
    cell = row.createCell(0);
    cell.setCellValue("ID");
    cell.setCellStyle(style);


    cell = row.createCell(1);
    cell.setCellValue("显示名");
    cell.setCellStyle(style);

    cell = row.createCell(2);
    cell.setCellValue("用户名");
    cell.setCellStyle(style);

    cell = row.createCell(3);
    cell.setCellValue("创建时间");
    cell.setCellStyle(style);
}

//生成Article表excel
@GetMapping(value = "/getart")
public String getArticle(HttpServletResponse response) throws Exception{
    HSSFWorkbook workbook = new HSSFWorkbook();
    HSSFSheet sheet = workbook.createSheet("统计表");
    createTitle(workbook,sheet);
    List<ArticleVO> rows = articleService.selectAll();

    //设置日期格式
    HSSFCellStyle style = workbook.createCellStyle();
    style.setDataFormat(HSSFDataFormat.getBuiltinFormat("m/d/yy h:mm"));

    //新增数据行，并且设置单元格数据
    int rowNum=1;
    for(ArticleVO articleVO:rows){
        HSSFRow row = sheet.createRow(rowNum);
        row.createCell(0).setCellValue(articleVO.getId());
        row.createCell(1).setCellValue(articleVO.getuId());
        row.createCell(2).setCellValue(articleVO.getTitle());
        row.createCell(3).setCellValue(articleVO.getContent());
        row.createCell(4).setCellValue(articleVO.getNickname());
      //  row.createCell(5).setCellValue(articleVO.getAvatar());
        HSSFCell cell = row.createCell(3);
        cell.setCellValue(articleVO.getCreateTime());
        cell.setCellStyle(style);
        rowNum++;
    }

    String fileName = "导出excel例子.xls";

    //生成excel文件
    buildExcelFile(fileName, workbook);

    //浏览器下载excel
    buildExcelDocument(fileName,workbook,response);

    return "download excel";
}

//生成excel文件
protected void buildExcelFile(String filename,HSSFWorkbook workbook) throws Exception{
    FileOutputStream fos = new FileOutputStream(filename);
    workbook.write(fos);
    fos.flush();
    fos.close();
}

//浏览器下载excel
protected void buildExcelDocument(String filename,HSSFWorkbook workbook,HttpServletResponse response) throws Exception{
    response.setContentType("application/vnd.ms-excel");
    response.setHeader("Content-Disposition", "attachment;filename="+ URLEncoder.encode(filename, "utf-8"));
    OutputStream outputStream = response.getOutputStream();
    workbook.write(outputStream);
    outputStream.flush();
    outputStream.close();
}

}