手把手教你springboot中導出數據到excel中
問題來源：
前一段時間公司的項目有個導出數據的需求，要求能夠實現全部導出也可以多選批量導出（雖然不是我負責的，我自己研究了研究），我們的項目是xboot前后端分離系統，后端的核心為SpringBoot 2.2.6.RELEASE，因此今天我主要講述后端的操作實現，為了簡化需求，我將需要導出的十幾個字段簡化為5個字段，導出的樣式模板如下：
實現步驟：
打開一個你平時練習使用的springboot的demo，開始按照以下步驟加入代碼進行操作。
1.添加maven依賴
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<!--Excel-->
<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>
3.11
</version>
</dependency>
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poi-ooxml是一個excel表格的操作工具包，處理的單頁數據量也是百萬級別的，因此我們選擇的是poi-ooxml.
2.編寫excel工具類
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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 {
/**
* 用戶信息導出類
* @param response 響應
* @param fileName 文件名
* @param columnList 每列的標題名
* @param dataList 導出的數據
*/
public
static
void
uploadExcelAboutUser(HttpServletResponse response,String fileName,List<String> columnList,<br>List<List<String>> dataList){
//聲明輸出流
OutputStream os =
null
;
//設置響應頭
setResponseHeader(response,fileName);
try
{
//獲取輸出流
os = response.getOutputStream();
//內存中保留1000條數據，以免內存溢出，其余寫入硬盤
SXSSFWorkbook wb =
new
SXSSFWorkbook(
1000
);
//獲取該工作區的第一個sheet
Sheet sheet1 = wb.createSheet(
"sheet1"
);
int
excelRow =
0
;
//創建標題行
Row titleRow = sheet1.createRow(excelRow++);
for
(
int
i =
0
;i<columnList.size();i++){
//創建該行下的每一列，並寫入標題數據
Cell cell = titleRow.createCell(i);
cell.setCellValue(columnList.get(i));
}
//設置內容行
if
(dataList!=
null
&& dataList.size()>
0
){
//序號是從1開始的
int
count =
1
;
//外層for循環創建行
for
(
int
i =
0
;i<dataList.size();i++){
Row dataRow = sheet1.createRow(excelRow++);
//內層for循環創建每行對應的列，並賦值
for
(
int
j = -
1
;j<dataList.get(
0
).size();j++){
//由於多了一列序號列所以內層循環從-1開始
Cell cell = dataRow.createCell(j+
1
);
if
(j==-
1
){
//第一列是序號列，不是在數據庫中讀取的數據，因此手動遞增賦值
cell.setCellValue(count++);
}
else
{
//其余列是數據列，將數據庫中讀取到的數據依次賦值
cell.setCellValue(dataList.get(i).get(j));
}
}
}
}
//將整理好的excel數據寫入流中
wb.write(os);
}
catch
(IOException e) {
e.printStackTrace();
}
finally
{
try
{
// 關閉輸出流
if
(os !=
null
) {
os.close();
}
}
catch
(IOException e) {
e.printStackTrace();
}
}
}
/*
設置瀏覽器下載響應頭
*/
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();
}
}
}
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網上的excel的工具類有很多，但很多並不是你復制過來就能直接使用的，因此需要我們深究其原理，這樣可以應對不同的場景寫出屬於我們自己的合適的代碼，這里就不一一解釋了，代碼中注釋加的很清楚，有不懂的可以留言評論。
3.編寫controller，service，serviceImpl，dao，entity
3.1 entity
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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 =
"唯一標識"
)
private
String id = String.valueOf(SnowFlakeUtil.getFlowIdInstance().nextId());
@ApiModelProperty
(value =
"創建者"
)
@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 =
"創建時間"
)
private
Date createTime;
@ApiModelProperty
(value =
"項目編號"
)
private
String itemNo;
@ApiModelProperty
(value =
"項目名稱"
)
private
String itemName;
@ApiModelProperty
(value =
"刪除標志 默認0"
)
private
Integer delFlag =
0
;
}
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3.2 dao
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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);
}
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3.3 service
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import
javax.servlet.http.HttpServletResponse;
import
java.util.List;
public
interface
TestService {
void
exportExcel(List<String> idList, HttpServletResponse response);
}
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3.4 serviceImpl
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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(
"序號"
,
"項目編碼"
,
"項目名稱"
,
"創建時間"
,
"創建人"
);
ExcelUtil.uploadExcelAboutUser(response,
"apply.xlsx"
,titleList,dataList);
}
}
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3.5 controller
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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 =
"導出excel"
,produces=
"application/octet-stream"
)
public
void
exportCorpLoanDemand(
@RequestBody
Map<String,List<String>> map, HttpServletResponse response){ ;
log.info(
"測試:{}"
,map);
testService.exportExcel(map.get(
"list"
),response);
}
}
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4.測試
測試的話可以使用swagger或者postman，甚至你前端技術足夠ok的話也可以寫個簡單的頁面進行測試，我是用的是swaager進行的測試，下面就是我測試的結果了：
原文鏈接：https://www.cnblogs.com/zaevn00001/p/13353744.html?utm_source=tuicool