前言

后台管理系统中数据展示一般都是用表格,表格会涉及到导入和导出;

1.导入

1.1 el-upload组件

1.导入是利用element-ui的Upload 上传组件;

<el-upload class="upload-demo"
        :action="importUrl"//上传的路径
        :name ="name"//上传的文件字段名
        :headers="importHeaders"//请求头格式
        :on-preview="handlePreview"//可以通过 file.response 拿到服务端返回数据
        :on-remove="handleRemove"//文件移除
        :before-upload="beforeUpload"//上传前配置
        :on-error="uploadFail"//上传错误
        :on-success="uploadSuccess"//上传成功
        :file-list="fileList"//上传的文件列表
        :with-credentials="withCredentials">//是否支持cookie信息发送
</el-upload>

1.2 原理：

里面对input进行了封装，并暴露一些方法和属性

1.3.ajax或者form上传？

可以设置http-request属性，覆盖默认的上传行为，可以自定义上传的实现

1.4 云端COS上传

这个一般还是很常见的，
原理是将文件存储到云端，返回一个存贮地址存在本地服务器，
cos存储过程：鉴权===分片上传===成功返回存储地址
tencent的cos存贮

2 导出

2.1 原理

导出是利用file的一个对象blob;
通过调用后台接口拿到数据,
然后用数据来实例化blob,
利用a标签的href属性链接到blob对象

2.2 代码示例

//声明导出文件名对象 
    const fileNames={
    1:'模板一',
    2:'模板二',
    3:'模板三',
    4:'模板四',
    }
     export const downloadTemplate = function (scheduleType) {
            axios.get('/demo/template', {
                params: {
                    "demoType": demoType
                },
                responseType: 'arraybuffer'
            }).then((response) => {
                //创建一个blob对象,file的一种
                let blob = new Blob([response.data], { type: 'application/x-xls' })
                let link = document.createElement('a')
                link.href = window.URL.createObjectURL(blob)
                //配置下载的文件名
                link.download = fileNames[scheduleType] + '_' + response.headers.datestr + '.xls'
                link.click()
            })
        }

3.完整代码

贴上整个小demo的完整代码,在后台开发可以直接拿过去用(vue文件)

<template>
<div>

  <el-table
    ref="multipleTable"
    :data="tableData3"
    tooltip-effect="dark"
    border
    style="width: 80%"
    @selection-change="handleSelectionChange">
    <el-table-column
      type="selection"
      width="55">
    </el-table-column>
    <el-table-column
      label="日期"
      width="120">
      <template slot-scope="scope">{{ scope.row.date }}</template>
    </el-table-column>
    <el-table-column
      prop="name"
      label="姓名"
      width="120">
    </el-table-column>
    <el-table-column
      prop="address"
      label="地址"
      show-overflow-tooltip>
    </el-table-column>
  </el-table>

  <div style="margin-top: 20px">
    <el-button @click="toggleSelection([tableData3[1], tableData3[2]])">切换第二、第三行的选中状态</el-button>
    <el-button @click="toggleSelection()">取消选择</el-button>
    <el-button type="primary" @click="importData">导入</el-button>
    <el-button type="primary" @click="outportData">导出</el-button>
  </div>

  <!-- 导入 -->
  <el-dialog title="导入" :visible.sync="dialogImportVisible" :modal-append-to-body="false" :close-on-click-modal="false" class="dialog-import">
      <div :class="{'import-content': importFlag === 1, 'hide-dialog': importFlag !== 1}">
        <el-upload class="upload-demo"
        :action="importUrl"
        :name ="name"
        :headers="importHeaders"
        :on-preview="handlePreview"
        :on-remove="handleRemove"
        :before-upload="beforeUpload"
        :on-error="uploadFail"
        :on-success="uploadSuccess"
        :file-list="fileList"
        :with-credentials="withCredentials">
        <!-- 是否支持发送cookie信息 -->
          <el-button size="small" type="primary" :disabled="processing">{{uploadTip}}</el-button>
          <div slot="tip" class="el-upload__tip">只能上传excel文件</div>
        </el-upload>
        <div class="download-template">
          <a class="btn-download" @click="download">
            <i class="icon-download"></i>下载模板</a>
        </div>
      </div>
      <div :class="{'import-failure': importFlag === 2, 'hide-dialog': importFlag !== 2}" >
        <div class="failure-tips">
          <i class="el-icon-warning"></i>导入失败</div>
        <div class="failure-reason">
          <h4>失败原因</h4>
          <ul>
            <li v-for="(error,index) in errorResults" :key="index">第{{error.rowIdx + 1}}行，错误：{{error.column}},{{error.value}},{{error.errorInfo}}</li>
          </ul>
        </div>
      </div>
    </el-dialog>

  <!-- 导出 -->
</div>
</template>

<script>
import * as scheduleApi from '@/api/schedule'
export default {
  data() {
    return {
      tableData3: [
        {
          date: "2016-05-03",
          name: "王小虎",
          address: "上海市普陀区金沙江路 1518 弄"
        },
        {
          date: "2016-05-02",
          name: "王小虎",
          address: "上海市普陀区金沙江路 1518 弄"
        }
      ],
      multipleSelection: [],
      importUrl:'www.baidu.com',//后台接口config.admin_url+'rest/schedule/import/'
      importHeaders:{
        enctype:'multipart/form-data',
        cityCode:''
      },
      name: 'import',
      fileList: [],
      withCredentials: true,
      processing: false,
      uploadTip:'点击上传',
      importFlag:1,
      dialogImportVisible:false,
      errorResults:[]
    };
  },

  methods: {
    toggleSelection(rows) {
      if (rows) {
        rows.forEach(row => {
          this.$refs.multipleTable.toggleRowSelection(row);
        });
      } else {
        this.$refs.multipleTable.clearSelection();
      }
    },
    handleSelectionChange(val) {
      //复选框选择回填函数,val返回一整行的数据
      this.multipleSelection = val;
    },
    importData() {
      this.importFlag = 1
      this.fileList = []
      this.uploadTip = '点击上传'
      this.processing = false
      this.dialogImportVisible = true
    },
    outportData() {
      scheduleApi.downloadTemplate()
    },
    handlePreview(file) {
      //可以通过 file.response 拿到服务端返回数据
    },
    handleRemove(file, fileList) {
      //文件移除
    },
    beforeUpload(file){
      //上传前配置
      this.importHeaders.cityCode='上海'//可以配置请求头
      let excelfileExtend = ".xls,.xlsx"//设置文件格式
      let fileExtend = file.name.substring(file.name.lastIndexOf('.')).toLowerCase();
      if (excelfileExtend.indexOf(fileExtend) <= -1) {
         this.$message.error('文件格式错误')
         return false
      }
      this.uploadTip = '正在处理中...'
      this.processing = true
    },
    //上传错误
    uploadFail(err, file, fileList) {
      this.uploadTip = '点击上传'
      this.processing = false
      this.$message.error(err)
    },
    //上传成功
    uploadSuccess(response, file, fileList) {
      this.uploadTip = '点击上传'
      this.processing = false
      if (response.status === -1) {
        this.errorResults = response.data
        if (this.errorResults) {
          this.importFlag = 2
        } else {
          this.dialogImportVisible = false
          this.$message.error(response.errorMsg)
        }
      } else {
        this.importFlag = 3
        this.dialogImportVisible = false
        this.$message.info('导入成功')
        this.doSearch()
      }
    },
    //下载模板
    download() {
      //调用后台模板方法,和导出类似
      scheduleApi.downloadTemplate()
    },
  }
};
</script>

<style scoped>
.hide-dialog{
  display:none;
}
</style>

js文件,调用接口

    import axios from 'axios'
    
    // 下载模板
    
        export const downloadTemplate = function (scheduleType) {
            axios.get('/rest/schedule/template', {
                params: {
                    "scheduleType": scheduleType
                },
                responseType: 'arraybuffer'
            }).then((response) => {
                //创建一个blob对象,file的一种
                let blob = new Blob([response.data], { type: 'application/x-xls' })
                let link = document.createElement('a')
                link.href = window.URL.createObjectURL(blob)
                link.download = fileNames[scheduleType] + '_' + response.headers.datestr + '.xls'
                link.click()
            })
        }

结语

感谢看到这里,很实用的导入导出功能代码,欢迎交流!
圣诞节快到了,祝大家Merry Christmas!