spring boot 导出数据到excel的操作步骤(demo)

2024-04-02 19:04:59 621人浏览独家记忆

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摘要

目录问题来源：实现步骤：1.添加Maven依赖2.编写excel工具类3.编写controller，service，serviceImpl，dao，entity3.1entity3.

问题来源：

前一段时间公司的项目有个导出数据的需求，要求能够实现全部导出也可以多选批量导出（虽然不是我负责的，我自己研究了研究），我们的项目是xboot前后端分离系统，后端的核心为SpringBoot 2.2.6.RELEASE，因此今天我主要讲述后端的操作实现，为了简化需求，我将需要导出的十几个字段简化为5个字段，导出的样式模板如下：

实现步骤：

打开一个你平时练习使用的springboot的demo，开始按照以下步骤加入代码进行操作。

1.添加maven依赖

<!--Excel-->
<dependency>
    <groupId>org.apache.poi</groupId>
    <artifactId>poi-ooxml</artifactId>
    <version>3.11</version>
</dependency>

poi-ooxml是一个excel表格的操作工具包，处理的单页数据量也是百万级别的，因此我们选择的是poi-ooxml.

2.编写excel工具类

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import javax.servlet.Http.httpservletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.List;
 
public class ExcelUtil {
    
    public static void uploadExcelAboutUser(HttpServletResponse response,String fileName,List<String> columnList,<br>List<List<String>> dataList){
        //声明输出流
        OutputStream os = null;
        //设置响应头
        setResponseHeader(response,fileName);
        try {
            //获取输出流
            os = response.getOutputStream();
            //内存中保留1000条数据，以免内存溢出，其余写入硬盘
            SXSSFWorkbook wb = new SXSSFWorkbook(1000);
            //获取该工作区的第一个sheet
            Sheet sheet1 = wb.createSheet("sheet1");
            int excelRow = 0;
            //创建标题行
            Row titleRow = sheet1.createRow(excelRow++);
            for(int i = 0;i<columnList.size();i++){
                //创建该行下的每一列，并写入标题数据
                Cell cell = titleRow.createCell(i);
                cell.setCellValue(columnList.get(i));
            }
            //设置内容行
            if(dataList!=null && dataList.size()>0){
                //序号是从1开始的
                int count = 1;
                //外层for循环创建行
                for(int i = 0;i<dataList.size();i++){
                    Row dataRow = sheet1.createRow(excelRow++);
                    //内层for循环创建每行对应的列，并赋值
                    for(int j = -1;j<dataList.get(0).size();j++){//由于多了一列序号列所以内层循环从-1开始
                        Cell cell = dataRow.createCell(j+1);
                        if(j==-1){//第一列是序号列，不是在数据库中读取的数据，因此手动递增赋值
                            cell.setCellValue(count++);
                        }else{//其余列是数据列，将数据库中读取到的数据依次赋值
                            cell.setCellValue(dataList.get(i).get(j));
                        }
                    }
                }
            }
            //将整理好的excel数据写入流中
            wb.write(os);
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                // 关闭输出流
                if (os != null) {
                    os.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
 
    
    private static void setResponseHeader(HttpServletResponse response, String fileName) {
        try {
            try {
                fileName = new String(fileName.getBytes(),"ISO8859-1");
            } catch (UnsupportedEncodingException e) {
                e.printStackTrace();
            }
            response.setContentType("application/octet-stream;charset=UTF-8");
            response.setHeader("Content-Disposition", "attachment;filename="+ fileName);
            response.addHeader("Pargam", "no-cache");
            response.addHeader("Cache-Control", "no-cache");
        } catch (Exception ex) {
            ex.printStackTrace();
        }
    }
}

网上的excel的工具类有很多，但很多并不是你复制过来就能直接使用的，因此需要我们深究其原理，这样可以应对不同的场景写出属于我们自己的合适的代码，这里就不一一解释了，代码中注释加的很清楚，有不懂的可以留言评论。

3.编写controller，service，serviceImpl，dao，entity

3.1 entity

import io.swagger.annotations.apiModelProperty;
import lombok.Data;
import org.hibernate.annotations.Where;
import javax.persistence.*;
import java.math.BigDecimal;
 
@Data
@Entity
@Where(clause = "del_flag = 0")
@Table(name = "t_scf_item_data")
public class ItemData{
    private static final long serialVersionUID = 1L;
    @Id
    @TableId
    @ApiModelProperty(value = "唯一标识")
    private String id = String.valueOf(SnowFlakeUtil.getFlowIdInstance().nextId());
    @ApiModelProperty(value = "创建者")
    @CreatedBy
    private String createBy;
    @CreatedDate
    @JSONFORMat(timezone = "GMT+8", pattern = "yyyy-MM-dd HH:mm:ss")
    @DateTimeFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    @ApiModelProperty(value = "创建时间")
    private Date createTime;
    
    @ApiModelProperty(value = "项目编号")
    private String itemNo;
    @ApiModelProperty(value = "项目名称")
    private String itemName;
     
    @ApiModelProperty(value = "删除标志 默认0")
    private Integer delFlag = 0;   
}

3.2 dao

import cn.exrick.xboot.modules.item.entity.ItemData;
import org.springframework.data.jpa.repository.Query;
import org.springframework.stereotype.Repository;
import java.util.List;
 
@Repository
public interface ItemDataDao{
　　@Query(value = "select a.item_no,a.item_name,concat(a.create_time),a.create_by from t_scf_item_data a where a.del_flag = 0 limit 5",nativeQuery = true)
    List<List<String>> findAllObject();
    @Query(value = "select a.item_no,a.item_name,concat(a.create_time),a.create_by  from t_scf_item_data a where a.del_flag = 0 and a.id in ?1 limit 5",nativeQuery = true)
    List<List<String>> findByIds(List<String> idList);
}

3.3 service

import javax.servlet.http.HttpServletResponse;
import java.util.List;
 
public interface TestService {
    void exportExcel(List<String> idList, HttpServletResponse response);
}

3.4 serviceImpl

import cn.exrick.xboot.common.utils.ExcelUtil;
import cn.exrick.xboot.modules.item.dao.ItemDataDao;
import cn.exrick.xboot.modules.item.service.TestService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;
import javax.servlet.http.HttpServletResponse;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
 
@Transactional
@Service
public class TestServiceImpl implements TestService {
 
    @Autowired
    private ItemDataDao itemDataDao;
    @Override
    public void exportExcel(List<String> idList, HttpServletResponse response) {
        List<List<String>> dataList = new ArrayList<>();
        if(idList == null || idList.size() == 0){
              dataList = itemDataDao.findAllObject();
        }else{
              dataList = itemDataDao.findByIds(idList);
        }
        List<String> titleList = Arrays.asList("序号","项目编码", "项目名称", "创建时间", "创建人");
        ExcelUtil.uploadExcelAboutUser(response,"apply.xlsx",titleList,dataList);
    }
}

3.5 controller

import cn.exrick.xboot.modules.item.service.TestService;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.WEB.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;
 
import javax.servlet.http.HttpServletResponse;
import java.util.List;
import java.util.Map;
@Slf4j
@RestController
@RequestMapping("/test")
public class TestController {
 
    @Autowired
    private TestService testService;
 
    @RequestMapping(value = "/exportExcel", method = RequestMethod.POST)
    @ApiOperation(value = "导出excel",produces="application/octet-stream")
    public void exportCorpLoanDemand(@RequestBody Map<String,List<String>> map, HttpServletResponse response){ ;
        log.info("测试:{}",map);
        testService.exportExcel(map.get("list"),response);
    }
}