springboot + EasyExcel 实现操作Excel文件

迷南。 2024-04-05 07:05 104阅读 0赞

### EasyExcel简介 ###

##### EasyExcel特点 #####

*  Java领域解析、生成Excel比较有名的框架有Apache  
    poi、jxl等。但他们都存在一个严重的问题就是非常的耗内存。如果你的系统并发量不大的话可能还行，但是一旦并发上来后一定会OOM或者JVM频繁的full gc。
 *  EasyExcel是阿里巴巴开源的一个excel处理框架，以使用简单、节省内存著称。EasyExcel能大大减少占用内存的主要原因是在解析Excel时没有将文件数据一次性全部加载到内存中，而是从磁盘上一行行读取数据，逐个解析。
 *  EasyExcel采用一行一行的解析模式，并将一行的解析结果以观察者的模式通知处理（AnalysisEventListener）。

### 引入依赖easyExcel相关依赖 ###

<dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi</artifactId>
        <version>${poi.version}</version>
    </dependency>
    
    <dependency>
        <groupId>org.apache.poi</groupId>
        <artifactId>poi-ooxml</artifactId>
        <version>${poi.version}</version>
    </dependency>
    <dependency>
        <groupId>com.alibaba</groupId>
        <artifactId>easyexcel</artifactId>
        <version>2.1.1</version>
    </dependency>

### 实现写 ###

##### 1、实体类 #####

@Data
    public class DemoData {
        
        //设置excel表头名称
        @ExcelProperty(value = "学生编号",index = 0)
        private Integer sno;
        @ExcelProperty(value = "学生姓名",index = 1)
        private String sname;
    }

##### 2、测试类 #####

public static void main(String[] args) {
        
        //实现excel写的操作
        //1 设置写入文件夹地址和excel文件名称
        String filename = "E:\\aaaaa\\www.xlsx";
        //2 调用easyexcel里面的方法实现写操作
        //write方法两个参数：第一个参数文件路径名称，第二个参数实体类class
        EasyExcel.write(filename,DemoData.class).sheet("学生列表").doWrite(getData());
    }
    
    //创建方法返回list集合
    private static List<DemoData> getData() {
        
        List<DemoData> list = new ArrayList<>();
        for (int i = 0; i < 10; i++) {
        
            DemoData data = new DemoData();
            data.setSno(i);
            data.setSname("lucy"+i);
            list.add(data);
        }
        return list;
    }

##### 4、查看文件 #####

![在这里插入图片描述][e7bd92536543408380eb8f885dce57de.png]![在这里插入图片描述][71ef4da4d0d74d9a91ee882774f0f21e.png]

### 实现读 ###

##### 1、实体类 #####

##### 2、监听类 #####

public class ExcelListener extends AnalysisEventListener<DemoData> {
        
        //一行一行读取excel内容
        @Override
        public void invoke(DemoData data, AnalysisContext analysisContext) {
        
            System.out.println("****"+data);
        }
        //读取表头内容
        @Override
        public void invokeHeadMap(Map<Integer, String> headMap, AnalysisContext context) {
        
            System.out.println("表头："+headMap);
        }
        //读取完成之后
        @Override
        public void doAfterAllAnalysed(AnalysisContext analysisContext) {
         }
    }

##### 3、测试类 #####

public static void main(String[] args) {
        
        //实现excel读操作
        String filename = "E:\\aaaaa\\www.xlsx";
        EasyExcel.read(filename,DemoData.class,new ExcelListener()).sheet().doRead();
    }

运行结果  
![在这里插入图片描述][3a070ad1aa7c4f3ba02a894e15107af2.png]

### 项目整合EasyExcel-前端 ###

##### 1.1、编辑Excel模板 #####

##### 1.2、Excel模板放入vue项目目录中 #####

![在这里插入图片描述][d1ba6a48fa6f4f4ca087aaa3f87f31ad.png]

##### 1.3、配置路由 #####

{
        
        path: '/subject',
        component: Layout,
        redirect: '/subject/list',
        name: '课程分类管理',
        meta: {
         title: '课程分类管理', icon: 'example' },
        children: [
          {
        
            path: 'list',
            name: '课程分类列表',
            component: () => import('@/views/edu/subject/list'),
            meta: {
         title: '课程分类列表', icon: 'table' }
          },
          {
        
            path: 'save',
            name: '添加课程分类',  
            component: () => import('@/views/edu/subject/save'),
            meta: {
         title: '添加课程分类', icon: 'tree' }
          }
        ]
      },

![在这里插入图片描述][4de4f314044a46db87340d1cf1adec16.png]

##### 1.4、添加vue组件 #####

![在这里插入图片描述][8fab66ddc8844891a4efbf0d27374f7e.png]

save.vue的代码

<template>
        <div class="app-container">
          <el-form label-width="120px">
            <el-form-item label="信息描述">
              <el-tag type="info">excel模版说明</el-tag>
              <el-tag>
                <i class="el-icon-download"/>
                <a :href="'/static/01.xlsx'">点击下载模版</a>
              </el-tag>
      
            </el-form-item>
      
            <el-form-item label="选择Excel">
              <el-upload
                ref="upload"
                :auto-upload="false"
                :on-success="fileUploadSuccess"
                :on-error="fileUploadError"
                :disabled="importBtnDisabled"
                :limit="1"
                :action="BASE_API+'/eduservice/subject/addSubject'"
                name="file"
                accept="application/vnd.ms-excel">
                <el-button slot="trigger" size="small" type="primary">选取文件</el-button>
                <el-button
                  :loading="loading"
                  style="margin-left: 10px;"
                  size="small"
                  type="success"
                  @click="submitUpload">上传到服务器</el-button>
              </el-upload>
            </el-form-item>
          </el-form>
        </div>
      </template>
      <script>
      export default {
        
          data() {
        
              return {
        
                  BASE_API: process.env.BASE_API, // 接口API地址
                  importBtnDisabled: false, // 按钮是否禁用,
                  loading: false
              }
          },
          created() {
        
      
          },
          methods:{
        
              //点击按钮上传文件到接口里面
              submitUpload() {
        
                  this.importBtnDisabled = true
                  this.loading = true
                  // js: document.getElementById("upload").submit()
                  this.$refs.upload.submit()
              },
              //上传成功
              fileUploadSuccess(response) {
        
                  //提示信息
                  this.loading = false
                  this.$message({
        
                      type: 'success',
                      message: '添加课程分类成功'
                  })
                  //跳转课程分类列表
                  //路由跳转
                  this.$router.push({
        path:'/subject/list'})
              },
              //上传失败
              fileUploadError() {
        
                  this.loading = false
                  this.$message({
        
                      type: 'error',
                      message: '添加课程分类失败'
                  })
              }
          }
      }
      </script>

### 项目整合EasyExcel-后端 ###

##### 2.1、引入依赖，依赖同上 #####

##### 2.2、创建和Excel对应的实体类 #####

@Data
    public class SubjectData {
        
        @ExcelProperty(index = 0)
        private String oneSubjectName;
        @ExcelProperty(index = 1)
        private String twoSubjectName;
    }

##### 2.3、controller层 #####

@RestController
    @RequestMapping("/eduservice/subject")
    @CrossOrigin
    public class EduSubjectController {
        
        @Autowired
        private EduSubjectService subjectService;
    
        //添加课程分类
        //获取上传过来文件，把文件内容读取出来
        @PostMapping("addSubject")
        public R addSubject(MultipartFile file) {
        
            //上传过来excel文件
            subjectService.saveSubject(file,subjectService);
            return R.ok();
        }
    }

##### 2.4、service层 #####

//添加课程分类
        @Override
        public void saveSubject(MultipartFile file, EduSubjectService subjectService) {
        
            try {
        
                //文件输入流
                InputStream in = file.getInputStream();
                //调用方法进行读取
                EasyExcel.read(in, SubjectData.class,new SubjectExcelListener(subjectService)).sheet().doRead();
            }catch(Exception e){
        
                e.printStackTrace();
            }
        }

##### 2.5、创建读取Excel监听器 #####

public class SubjectExcelListener extends AnalysisEventListener<SubjectData> {
        
    
        //因为SubjectExcelListener不能交给spring进行管理，需要自己new，不能注入其他对象
        //不能实现数据库操作
        public EduSubjectService subjectService;
        public SubjectExcelListener() {
        }
        public SubjectExcelListener(EduSubjectService subjectService) {
        
            this.subjectService = subjectService;
        }
    
        //读取excel内容，一行一行进行读取
        @Override
        public void invoke(SubjectData subjectData, AnalysisContext analysisContext) {
        
            if(subjectData == null) {
        
                throw new GuliException(20001,"文件数据为空");
            }
    
            //一行一行读取，每次读取有两个值，第一个值一级分类，第二个值二级分类
            //判断一级分类是否重复
            EduSubject existOneSubject = this.existOneSubject(subjectService, subjectData.getOneSubjectName());
            if(existOneSubject == null) {
         //没有相同一级分类，进行添加
                existOneSubject = new EduSubject();
                existOneSubject.setParentId("0");
                existOneSubject.setTitle(subjectData.getOneSubjectName());//一级分类名称
                subjectService.save(existOneSubject);
            }
    
            //获取一级分类id值
            String pid = existOneSubject.getId();
    
            //添加二级分类
            //判断二级分类是否重复
            EduSubject existTwoSubject = this.existTwoSubject(subjectService, subjectData.getTwoSubjectName(), pid);
            if(existTwoSubject == null) {
        
                existTwoSubject = new EduSubject();
                existTwoSubject.setParentId(pid);
                existTwoSubject.setTitle(subjectData.getTwoSubjectName());//二级分类名称
                subjectService.save(existTwoSubject);
            }
        }
    
        //判断一级分类不能重复添加
        private EduSubject existOneSubject(EduSubjectService subjectService,String name) {
        
            QueryWrapper<EduSubject> wrapper = new QueryWrapper<>();
            wrapper.eq("title",name);
            wrapper.eq("parent_id","0");
            EduSubject oneSubject = subjectService.getOne(wrapper);
            return oneSubject;
        }
    
        //判断二级分类不能重复添加
        private EduSubject existTwoSubject(EduSubjectService subjectService,String name,String pid) {
        
            QueryWrapper<EduSubject> wrapper = new QueryWrapper<>();
            wrapper.eq("title",name);
            wrapper.eq("parent_id",pid);
            EduSubject twoSubject = subjectService.getOne(wrapper);
            return twoSubject;
        }
    
        @Override
        public void doAfterAllAnalysed(AnalysisContext analysisContext) {
        
    
        }
    }

### 页面操作展示 ###

##### 3.1、下载模板 #####

![在这里插入图片描述][5b2ee779f18b46e8967db6b69034ff4d.png]![在这里插入图片描述][816aeab0d1474f87a3a479735fef3996.png]

##### 3.2、编写导入的信息 #####

![在这里插入图片描述][e9b6218f95504ddd95aa3ee02c6c08d0.png]

##### 3.3、选择需要导入的表![在这里插入图片描述][2bb772cc558144498c62d77825c846c2.png] #####

##### 3.4、确认上传 #####

![在这里插入图片描述][46c6a0a362f5478192107e3aa6882dde.png]

导入成功，跳转到列表信息

![在这里插入图片描述][759639c615ee4cd6a83067d62082a4a5.png]  
结束！！！！

--------------------

当我站在瀑布前，觉得非常的难过，我总觉得，应该是两个人站在这里。

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[5b2ee779f18b46e8967db6b69034ff4d.png]: https://img-blog.csdnimg.cn/5b2ee779f18b46e8967db6b69034ff4d.png
[816aeab0d1474f87a3a479735fef3996.png]: https://image.dandelioncloud.cn/pgy_files/images/2024/04/04/12d31d17335f4636b1a74978f5183ef6.png
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