本篇内容介绍了“怎么使用Java+element实现excel导入和导出”的有关知识，在实际案例的操作过程中，不少人都会遇到这样的困境，接下来就让小编带领大家学习一下如何处理这些情况吧！希望大家仔细阅读，能够学有所成！
本项目是前端vue3，后端springboot开发 需求为：前端导入表格，后端处理表格存储数据，点击按钮可以导出表格。
上传效果：前端点击上传按钮，会跳出选择文件框，选择文件，点击上传。
导出效果：前端点击导出按钮，会跳出下载框，选择位置自动下载。
上传效果图：
下载效果图：
一、上传excel前端代码
<el-upload ref="file" class="upload-demo" :limit="1" accept=".xlsx, .xls" action="http://localhost:8081/admin/perform/importexcel" auto-upload="false" > <template #trigger> <el-button type="primary">选择文件</el-button> </template> <el-button class="ml-3" type="success" @click="submitUpload" > 上传文件 </el-button> 仅允许导入xls、xlsx格式文件。 </el-upload>
import { ref, reactive, computed } from "vue"
import { ElMessage, UploadInstance } from "element-plus"
const file = ref<UploadInstance>()
const submitUpload = () => {
file.value!.submit()
ElMessage({
message: "上传成功",
type: "success",
})
window.location.reload()
}效果图
二、上传excel后端代码
Controller层
@PostMapping("/importexcel")
public Result importData(MultipartFile file) throws Exception {
return performService.importData(file.getInputStream());
}Service层
@Override
public Result importData(InputStream inputStream) throws IOException {
// Perform根据自己表格的表头创建的实体，要意义对应
List<Perform> res = new ArrayList<>();
try {
ins = (FileInputStream) inputStream;
//true xls文件，false xlsx文件
Workbook workbook = null;
// XSSFWorkbook instance of HSSFWorkbook 所以通用
workbook = new XSSFWorkbook(ins);
//获取工作表
Sheet sheet = workbook.getSheetAt(0);
//获取表头
Row rowHead = sheet.getRow(0);
//判断表头是否正确
if (rowHead.getPhysicalNumberOfCells() < 1) {
return Result.error("表头错误");
}
//获取数据
for (int i = 1; i <= sheet.getLastRowNum(); i++) {
//获取第一行的用户信息
Row row = sheet.getRow(i);
String tId;
if (row.getCell(0) == null) {
tId = "";
row.createCell(0).setCellValue(tId);
} else {
//先设置为字符串再作为数字读出来
row.getCell(0).setCellType(CellType.STRING);
tId = row.getCell(0).getStringCellValue();
}
String tName;
if (row.getCell(1) == null) {
tName = "";
row.createCell(1).setCellValue(tName);
} else {
tName = row.getCell(1).getStringCellValue();
}
String tDept;
if (row.getCell(2) == null) {
tDept = "";
row.createCell(2).setCellValue(tDept);
} else {
tDept = row.getCell(2).getStringCellValue();
}
....................
Perorm perform=new Perform()
xxxset创建实体
System.out.println(perform);
res.add(perform);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (ins != null) {
try {
ins.close();
} catch (IOException e) {
e.printStackTrace();
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
new Thread(() -> {
//批处理比较快
batchInsert(res);
}).start();
return Result.success(res);
}
/**
* 批量插入更快
*
* @param performList
*/
private void batchInsert(List<Perform> performList) {
SqlSession sqlSession = sqlSessionFactory.openSession(ExecutorType.BATCH, false);
performList.stream().forEach(perform -> {
performMapper.insert(perform);
});
sqlSession.commit();
sqlSession.clearCache();
}三、下载excel前端代码
<el-button type="warning" @click="exportInfo()" > <a href="https://www.maopiaopiao.com">
const exportInfo = () => {
ElMessage({
message: "请稍等",
type: "warning",
})
}四、下载excel后端代码
Controller层
/**
* 导出表格
*
* @return
*/
@GetMapping("/exportexcel")
public void exportExcel(HttpServletResponse response) throws Exception {
performService.exportExcel(response);
}Service层
@Override
public void exportExcel(HttpServletResponse response) throws IOException {
System.out.println("导出表格");
List<Perform> list = performMapper.selectList(new QueryWrapper<>());
String sheetName = "教师业绩表";
Map<String, String> titleMap = new LinkedHashMap<>();
titleMap.put("tId", "教师工号");
titleMap.put("tName", "教师姓名");
.....根据自己的表头来
ExportExcel.excelExport(response, list, titleMap, sheetName);
}ExportExcel类：
package com.performance.back.common.utils;
import com.baomidou.mybatisplus.core.toolkit.ObjectUtils;
import com.performance.back.admin.dao.entity.Perform;
import org.apache.poi.hssf.usermodel.*;
import org.apache.poi.ss.usermodel.*;
import org.apache.poi.ss.util.CellRangeAddress;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import java.util.Map;
/**
* @ClassName ExportExcel
* @Descriotion TODO
* @Author nitaotao
* @Date 2022/11/14 11:55
* @Version 1.0
**/
public class ExportExcel {
private ExportExcel() {
}
/***
* 工作簿
*/
private static HSSFWorkbook workbook;
/***
* sheet
*/
private static HSSFSheet sheet;
/***
* 标题行开始位置
*/
private static final int TITLE_START_POSITION = 0;
/***
* 时间行开始位置
*/
private static final int DATEHEAD_START_POSITION = 1;
/***
* 表头行开始位置
*/
private static final int HEAD_START_POSITION = 0;
/***
* 文本行开始位置
*/
private static final int CONTENT_START_POSITION = 1;
/***
*
* @param sheetName
* sheetName
*/
private static void initHSSFWorkbook(String sheetName) {
workbook = new HSSFWorkbook();
sheet = workbook.createSheet(sheetName);
sheet.setDefaultColumnWidth(15);
}
/**
* 生成标题（第零行创建）
*
* @param titleMap 对象属性名称->表头显示名称
* @param sheetName sheet名称
*/
private static void createTitleRow(Map<String, String> titleMap, String sheetName) {
CellRangeAddress titleRange = new CellRangeAddress(0, 0, 0, titleMap.size() - 1);
sheet.addMergedRegion(titleRange);
HSSFRow titleRow = sheet.createRow(TITLE_START_POSITION);
HSSFCell titleCell = titleRow.createCell(0);
titleCell.setCellValue(sheetName);
}
/**
* 创建时间行（第一行创建）
*
* @param titleMap 对象属性名称->表头显示名称
*/
private static void createDateHeadRow(Map<String, String> titleMap) {
CellRangeAddress dateRange = new CellRangeAddress(1, 1, 0, titleMap.size() - 1);
sheet.addMergedRegion(dateRange);
HSSFRow dateRow = sheet.createRow(DATEHEAD_START_POSITION);
HSSFCell dateCell = dateRow.createCell(0);
dateCell.setCellValue(new SimpleDateFormat("yyyy年MM月dd日").format(new Date()));
}
/**
* 创建表头行（第二行创建）
*
* @param titleMap 对象属性名称->表头显示名称
*/
private static void createHeadRow(Map<String, String> titleMap) {
// 第1行创建
HSSFRow headRow = sheet.createRow(HEAD_START_POSITION);
headRow.setHeight((short) 900);
int i = 0;
for (String entry : titleMap.keySet()) {
// 生成一个样式
HSSFCellStyle style = workbook.createCellStyle();
// 设置这些样式
style.setAlignment(HorizontalAlignment.CENTER);//水平居中
style.setVerticalAlignment(VerticalAlignment.CENTER);//垂直居中
// 设置边框
style.setBorderBottom(BorderStyle.THIN);
style.setBorderLeft(BorderStyle.THIN);
style.setBorderRight(BorderStyle.THIN);
style.setBorderTop(BorderStyle.THIN);
// 自动换行
style.setWrapText(true);
// 生成一个字体
HSSFFont font = workbook.createFont();
font.setFontHeightInPoints((short) 10);
font.setColor(IndexedColors.WHITE.index);
font.setBold(false);
font.setFontName("宋体");
// 把字体 应用到当前样式
style.setFont(font);
//style设置好后，为cell设置样式
HSSFCell headCell = headRow.createCell(i);
headCell.setCellValue(titleMap.get(entry));
if (i > 14) {
// 背景色
style.setFillForegroundColor(IndexedColors.BLUE.index);
style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
style.setFillBackgroundColor(IndexedColors.BLUE.index);
} else if (i > 10) {
style.setFillForegroundColor(IndexedColors.BLACK.index);
style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
style.setFillBackgroundColor(IndexedColors.BLACK.index);
} else if (i > 7) {
style.setFillForegroundColor(IndexedColors.BLUE.index);
style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
style.setFillBackgroundColor(IndexedColors.BLUE.index);
} else if (i >4) {
style.setFillForegroundColor(IndexedColors.RED.index);
style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
style.setFillBackgroundColor(IndexedColors.RED.index);
} else {
style.setFillForegroundColor(IndexedColors.GREEN.index);
style.setFillPattern(FillPatternType.SOLID_FOREGROUND);
style.setFillBackgroundColor(IndexedColors.GREEN.index);
}
headCell.setCellStyle(style);
i++;
}
}
/**
* @param dataList 对象数据集合
* @param titleMap 表头 信息
*/
private static void createContentRow(List<?> dataList, Map<String, String> titleMap) {
try {
int i = 0;
// 生成一个样式
HSSFCellStyle style = workbook.createCellStyle();
// 设置这些样式
style.setAlignment(HorizontalAlignment.CENTER);//水平居中
style.setVerticalAlignment(VerticalAlignment.CENTER);//垂直居中
// 设置边框
style.setBorderBottom(BorderStyle.THIN);
style.setBorderLeft(BorderStyle.THIN);
style.setBorderRight(BorderStyle.THIN);
style.setBorderTop(BorderStyle.THIN);
// 自动换行
style.setWrapText(true);
// 生成一个字体
HSSFFont font = workbook.createFont();
font.setFontHeightInPoints((short) 10);
font.setColor(IndexedColors.BLACK.index);
font.setBold(false);
font.setFontName("宋体");
// 把字体 应用到当前样式
style.setFont(font);
//style设置好后，为cell设置样式
for (Object obj : dataList) {
HSSFRow textRow = sheet.createRow(CONTENT_START_POSITION + i);
int j = 0;
for (String entry : titleMap.keySet()) {
//属性名驼峰式
String method = "get" + entry.substring(0, 1).toUpperCase() + entry.substring(1);
// System.out.println("调用" + method + "方法");
//反射调用
Method m = obj.getClass().getMethod(method, null);
Object value = m.invoke(obj, null);
HSSFCell textcell = textRow.createCell(j);
if (ObjectUtils.isNotEmpty(value)) {
textcell.setCellValue(value.toString());
} else {
textcell.setCellValue("");
}
textcell.setCellStyle(style);
j++;
}
i++;
}
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* 自动伸缩列（如非必要，请勿打开此方法，耗内存）
*
* @param size 列数
*/
private static void autoSizeColumn(Integer size) {
for (int j = 0; j < size; j++) {
sheet.autoSizeColumn(j);
}
}
public static void excelExport( HttpServletResponse response, List<Perform> list, Map<String, String> titleMap, String sheetName) throws IOException {
//生成表格的不可重复名
Date date = new Date();
// 初始化workbook
initHSSFWorkbook(sheetName);
// 表头行
createHeadRow(titleMap);
// 文本行
createContentRow(list, titleMap);
//输出Excel文件
OutputStream output=response.getOutputStream();
response.reset();
//设置响应头，
response.setHeader("Content-disposition", "attachment; filename=teacher.xls");
response.setContentType("application/msexcel");
workbook.write(output);
output.close();
}
}