目录
一、POI导入导出
CREATE TABLE `test_student` (
`id` int NOT NULL AUTO_INCREMENT PRIMARY KEY,
`name` varchar(255) DEFAULT NULL,
`age` int DEFAULT NULL
);<dependency>
<groupId>org.apache.poi</groupId>
<artifactId>poi-ooxml</artifactId>
<version>4.1.2</version>
</dependency>1.数据库导出为Excel文件
@Test
void f1() {
// 数据库导出为Excel文件
List<TestStudent> list = testStudentService.list();
// 导出的位置
String path = "D:\\save\\stu1.xlsx";
// 工作薄 workbook(Excel本身)->sheet页签工作表 -> 行->单元格
try (XSSFWorkbook workbook = new XSSFWorkbook()) {
// 新建 工作薄对象
// 新建sheet对象
XSSFSheet sheet = workbook.createSheet("test_stu");
//创建行
XSSFRow row0 = sheet.createRow(0);
// 创建单元格
row0.createCell(0).setCellValue("学生ID");
row0.createCell(1).setCellValue("学生姓名");
row0.createCell(2).setCellValue("学生年龄");
for (int i = 0; i < list.size(); i++) {
// 略过首行
XSSFRow row = sheet.createRow(i + 1);
TestStudent testStudent = list.get(i);
row.createCell(0).setCellValue(testStudent.getId());
row.createCell(1).setCellValue(testStudent.getName());
row.createCell(2).setCellValue(testStudent.getAge());
}
//内容写出去
workbook.write(new FileOutputStream(path));
} catch (IOException e) {
throw new RuntimeException(e);
}
}2.将Excel文件导入到数据库中
@Test
void f2() throws IOException {
// 将Excel文件导入到数据库中
ArrayList<TestStudent> stuList = new ArrayList<>();
// 导入的源文件
String path = "D:\\save\\stu1.xlsx";
// 工作薄对象
Workbook workbook = WorkbookFactory.create(new FileInputStream(path));
// 工作表 sheet
Sheet sheet = workbook.getSheetAt(0);
// 行
int rows = sheet.getPhysicalNumberOfRows();
// 行的头信息，第一行，可以不处理
for (int i = 1; i < rows; i++) {
Row row = sheet.getRow(i);
TestStudent student = new TestStudent();
// 第一个单元格,因为是主键,可以不要
// 第二个单元格
student.setName(row.getCell(1).getStringCellValue());
// 第三个单元格
student.setAge((int) row.getCell(2).getNumericCellValue());
// 把组装好的 student对象,存入集合
stuList.add(student);
// 不能循环调用数据库
// testStudentService.save(student);
}
// 存数据到 数据库
// 批量调用
testStudentService.saveBatch(stuList);
}
二、Hutool导入导出
Hutool官网：https://hutool.cn/
<dependency>
<groupId>cn.hutool</groupId>
<artifactId>hutool-all</artifactId>
<version>5.8.16</version>
</dependency>1.数据库导出为Excel文件——属性名是列名
@Test
void f1() {
List<TestStudent> list = testStudentService.list();
String path = "D:\\save\\stu2.xlsx";
// 属性名就是Excel的列名
ExcelWriter writer = ExcelUtil.getWriter(path);
writer.write(list);
writer.close();
}2.数据库导出为Excel文件——列名起别名
@Test
void f2() {
List<TestStudent> list = testStudentService.list();
String path = "D:\\save\\stu3.xlsx";
ExcelWriter writer = ExcelUtil.getWriter(path);
writer.addHeaderAlias("id", "学生ID");
writer.addHeaderAlias("name", "学生姓名");
writer.addHeaderAlias("age", "学生年龄");
writer.write(list);
writer.close();
}3.从Excel文件导入数据到数据库——属性名是列名
@Test
void f3() {
String path = "D:\\save\\stu2.xlsx";
ExcelReader reader = ExcelUtil.getReader(path);
List<TestStudent> list = reader.readAll(TestStudent.class);
testStudentService.saveBatch(list);
}4.从Excel文件导入数据到数据库——列名改为属性名
@Test
void f4() {
String path = "D:\\save\\stu3.xlsx";
ExcelReader reader = ExcelUtil.getReader(path);
// Excel列名信息与 属性不一致时，使用别名的方式读取
reader.addHeaderAlias("学生ID", "id");
reader.addHeaderAlias("学生姓名", "name");
reader.addHeaderAlias("学生年龄", "age");
List<TestStudent> list = reader.readAll(TestStudent.class);
testStudentService.saveBatch(list);
}
三、EasyExcel
官网：https://easyexcel.opensource.alibaba.com/
<dependency>
<groupId>com.alibaba</groupId>
<artifactId>easyexcel</artifactId>
<version>3.2.1</version>
</dependency>@Data
@AllArgsConstructor
@NoArgsConstructor
public class TestStudent extends Model<TestStudent> {
@TableId(type = IdType.AUTO)
@ExcelProperty("学生ID")
private Integer id;
@ExcelProperty("学生姓名")
private String name;
@ExcelProperty("年龄")
private Integer age;
}
1.数据库导出数据到一个sheet中
@Test
void f1() {
// 数据库导出为Excel文件
String path = "D:\\save\\stu4.xlsx";
List<TestStudent> list = testStudentService.list();
EasyExcel.write(path, TestStudent.class).sheet(0, "学生信息").doWrite(list);
}2.数据库导出数据到多个sheet中
@Test
void f2() {
// 数据库导出为Excel文件
String path = "D:\\save\\stu5.xlsx";
try (ExcelWriter excelWriter = EasyExcel.write(path, TestStudent.class).build()) {
long count = testStudentService.count();
long num = count % 100 == 0 ? count / 100 : count / 100 + 1;
for (int i = 0; i < num; i++) {
WriteSheet writeSheet = EasyExcel.writerSheet(i, "学生信息" + i).build();
List<TestStudent> pageList = testStudentService.pageList(i + 1, 100);
excelWriter.write(pageList, writeSheet);
}
} catch (Exception e) {
throw new RuntimeException(e);
}
}3.从Excel文件导入数据到数据库
@Test
void f3() {
String path = "D:\\save\\stu4.xlsx";
EasyExcel.read(path,TestStudent.class,new PageReadListener<TestStudent>(list->{
// 自带的分页读取，每次 只读取100条数据，防止数据量过大导致内存溢出
testStudentService.saveBatch(list);
})).sheet().doRead();
}4.读取大数据量Excel文件到数据库中
@Test
void f4() {
String path = "D:\\save\\stu10.xlsx";
EasyExcel.read(path, TestStudent.class, new ReadListener<TestStudent>() {
private static final int saveSize = 10000;
private List<TestStudent> saveList = ListUtils.newArrayListWithCapacity(saveSize);
// 每次读取一条，执行一次invoke方法
@Override
public void invoke(TestStudent testStudent, AnalysisContext analysisContext) {
saveList.add(testStudent);
if (saveList.size() >= saveSize) {
// 保存数据
saveData();
// 清空集合，重置集合
saveList = ListUtils.newArrayListWithCapacity(saveSize);
}
}
// 当所有的数据都读取完成时，会执行invoke方法，但是此时数据还未保存到数据库，所以需要执行doAfterAllAnalysed方法
@Override
public void doAfterAllAnalysed(AnalysisContext analysisContext) {
// 执行完了所有的方法，还有一些没凑够saveSize的数据，所以需要执行saveData方法进行存储
saveData();
}
private void saveData() {
testStudentService.saveBatch(saveList);
}
}).sheet().doRead();
}5.从页面上传Excel写入数据库
后端接口：
@RestController
@RequestMapping("/upload")
public class UploadController {
@Resource
TestStudentService testStudentService;
@PostMapping("/test1")
public R upload1(MultipartFile file) throws IOException {
// 该方法每次自动存100条数据到数据库
EasyExcel.read(
file.getInputStream(),
TestStudent.class,
new PageReadListener<TestStudent>(list -> {
testStudentService.saveBatch(list);
})).sheet().doRead();
return R.ok("上传成功");
}
}前端页面：Student.vue
<template>
<div class="common-layout">
<el-container>
<el-header>
<Top/>
</el-header>
<el-container>
<el-aside>
<Menu/>
</el-aside>
<el-main>
<el-row>
<el-col>
<el-upload ref="uploadRef" class="upload-demo"
action="http://localhost:8081/upload/test1"
:auto-upload="false"
:with-credentials="true"
:on-success="ups">
<template #trigger> <!--#trigger用于自定义触发上传、弹出对话框或其他交互操作的按钮或元素-->
<el-button type="primary">选择文件</el-button>
</template>
<el-button class="ml-4" type="success" @click="submitUpload">点击上传</el-button>
<template #tip> <!--#tip用于插入提示信息或其他额外内容-->
<div class="el-upload__tip"></div>
</template>
</el-upload>
</el-col>
</el-row>
<el-table :data="stuList" stripe style="width: 100%">
<el-table-column prop="id" label="学生ID" width="180"/>
<el-table-column prop="name" label="学生姓名" width="180"/>
<el-table-column prop="age" label="学生年龄"/>
</el-table>
</el-main>
</el-container>
</el-container>
</div>
</template>
<script setup>
import {ref, reactive, onMounted} from "vue";
import axios from '@/plugins/axios.js'
import {ElMessage} from 'element-plus'
import LoginUser from "@/stores/LoginUser.js";
import router from "@/router/index.js";
import Top from "@/components/Top.vue";
import Menu from "@/components/Menu.vue";
const uploadRef = ref([])
let submitUpload = () => {
uploadRef.value.submit()
}
let ups = (response, file, fileList) => {
console.log(response)
if (response.code === 200) {
ElMessage.success(response.msg)
query()
} else {
ElMessage.error(response.msg)
}
}
let stuList = ref([])
let query = () => {
let param = {
"pageNum": 1,
"pageSize": 10
}
axios.get("/test/stu/page", param)
.then(result => {
if (result.code === 200) {
stuList.value = result.data
}
})
}
onMounted(() => {
query()
})
</script>
<style scoped>
</style>路由：
import {createRouter, createWebHistory} from 'vue-router'
import HomeView from '../views/HomeView.vue'
import LoginView from '../views/LoginView.vue'
import TaskList from '../views/task/TaskList.vue'
import Student from '../views/test/Student.vue'
const router = createRouter({
history: createWebHistory(import.meta.env.BASE_URL),
routes: [
{
path: '/',
name: 'home',
component: HomeView,
}, {
path: '/login',
name: 'login',
component: LoginView,
}, {
path: '/task/list',
name: 'taskList',
component: TaskList
}, {
path: '/test',
name: 'test',
children: [
{
path: 'student',
name: 'student',
component: Student,
}
]
}
],
})
export default router
导出数据库到Excel后端接口：
@RestController
@RequestMapping("/export")
public class ExportController {
@Resource
HttpServletResponse response;
@Resource
private TestStudentService testStudentService;
@GetMapping("/stu/excel")
public void exportStuExcel() throws IOException {
//获取 需要导出的信息
List<TestStudent> list = testStudentService.list();
// 设置导出的文件名
// 这行代码将编码后的字符串中的所有 + 替换为 %20，这样可以确保文件名在下载时不会被错误地解释为空格。
String fileName = URLEncoder.encode("学生信息表", "UTF-8").replaceAll("\\+", "%20");
// 设置响应头信息
// response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
// response.setCharacterEncoding("utf-8");
response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
// 使用 filename* 参数可以正确处理包含非 ASCII 字符的文件名。
response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename*=utf-8''" + fileName + ".xlsx");
/* attachment：指示浏览器将文件作为附件下载。
filename*=utf-8''：使用 filename* 参数来支持非 ASCII 字符，utf-8 表示编码格式，'' 表示语言标签（通常为空）。
fileName + ".xlsx"：拼接编码后的文件名和文件扩展名。*/
// response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");
// 这行代码使用 EasyExcel 将 list 中的数据写入 Excel 文件，并将其输出到 response.getOutputStream()。
EasyExcel.write(response.getOutputStream(), TestStudent.class).sheet("数据1").doWrite(list);
// 不需要手动关闭 response.getOutputStream()，EasyExcel 会自动处理。
// response.getOutputStream().close();
}
}前端页面：
<el-col>
<a href="http://localhost:8081/export/stu/excel">导出全部数据</a>
</el-col>6.封装导出数据库到Excel工具类
@Component
public class ExportUtil<T> {
@Resource
HttpServletResponse response;
public void expExcel(String fileName, List<T> list, Class<T> tClass){
try {
fileName = URLEncoder.encode(fileName, "UTF-8").replaceAll("\\+", "%20");
// 设置响应头信息
// response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet");
// response.setCharacterEncoding("utf-8");
response.setContentType(MediaType.APPLICATION_OCTET_STREAM_VALUE);
// 使用 filename* 参数可以正确处理包含非 ASCII 字符的文件名。
response.setHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment;filename*=utf-8''" + fileName + ".xlsx");
/* attachment：指示浏览器将文件作为附件下载。
filename*=utf-8''：使用 filename* 参数来支持非 ASCII 字符，utf-8 表示编码格式，'' 表示语言标签（通常为空）。
fileName + ".xlsx"：拼接编码后的文件名和文件扩展名。*/
// response.setHeader("Content-disposition", "attachment;filename*=utf-8''" + fileName + ".xlsx");
// 这行代码使用 EasyExcel 将 list 中的数据写入 Excel 文件，并将其输出到 response.getOutputStream()。
EasyExcel.write(response.getOutputStream(), tClass).sheet("数据1").doWrite(list);
}catch (IOException e){
throw new RuntimeException(e);
}
}
}/**
* 使用工具类导出数据库到Excel
*/
@Resource
ExportUtil<TestStudent> exportUtil;
@GetMapping("/stu/excel2")
public void exportStuExcel2(){
exportUtil.expExcel("学生信息表", testStudentService.list(), TestStudent.class);
}