vue-element-admin项目导入和导出的实现

vue-element-admin导入组件封装

模板和样式

首先封装一个类似的组件，首先需要注意的是，类似功能，vue-element-admin已经提供了，我们只需要改造即可
excel导入功能需要使用npm包xlsx，所以需要安装xlsx插件

npm i xlsx

将vue-element-admin提供的导入功能新建一个组件，位置： src/components/UploadExcel

import CommonTools from './CommonTools'
import UploadExcel from './UploadExcel'
export default {
  install(Vue) {
    Vue.component('CommonTools', CommonTools) // 注册工具栏组件
    Vue.component('UploadExcel', UploadExcel) // 注册导入excel组件
  }
}

修改样式和布局

<template>
  <div class="upload-excel">
    <div class="btn-upload">
      <el-button :loading="loading" size="mini" type="primary" @click="handleUpload">
        点击上传
      </el-button>
    </div>

    <input ref="excel-upload-input" class="excel-upload-input" type="file" accept=".xlsx, .xls" @change="handleClick">
    <div class="drop" @drop="handleDrop" @dragover="handleDragover" @dragenter="handleDragover">
      <i class="el-icon-upload" />
      <span>将文件拖到此处</span>
    </div>
  </div>
</template>

<script>
import XLSX from 'xlsx'

export default {
  props: {
    beforeUpload: Function, // eslint-disable-line
    onSuccess: Function// eslint-disable-line
  },
  data() {
    return {
      loading: false,
      excelData: {
        header: null,
        results: null
      }
    }
  },
  methods: {
    generateData({ header, results }) {
      this.excelData.header = header
      this.excelData.results = results
      this.onSuccess && this.onSuccess(this.excelData)
    },
    handleDrop(e) {
      e.stopPropagation()
      e.preventDefault()
      if (this.loading) return
      const files = e.dataTransfer.files
      if (files.length !== 1) {
        this.$message.error('Only support uploading one file!')
        return
      }
      const rawFile = files[0] // only use files[0]

      if (!this.isExcel(rawFile)) {
        this.$message.error('Only supports upload .xlsx, .xls, .csv suffix files')
        return false
      }
      this.upload(rawFile)
      e.stopPropagation()
      e.preventDefault()
    },
    handleDragover(e) {
      e.stopPropagation()
      e.preventDefault()
      e.dataTransfer.dropEffect = 'copy'
    },
    handleUpload() {
      this.$refs['excel-upload-input'].click()
    },
    handleClick(e) {
      const files = e.target.files
      const rawFile = files[0] // only use files[0]
      if (!rawFile) return
      this.upload(rawFile)
    },
    upload(rawFile) {
      this.$refs['excel-upload-input'].value = null // fix can't select the same excel

      if (!this.beforeUpload) {
        this.readerData(rawFile)
        return
      }
      const before = this.beforeUpload(rawFile)
      if (before) {
        this.readerData(rawFile)
      }
    },
    readerData(rawFile) {
      this.loading = true
      return new Promise((resolve, reject) => {
        const reader = new FileReader()
        reader.onload = e => {
          const data = e.target.result
          const workbook = XLSX.read(data, { type: 'array' })
          const firstSheetName = workbook.SheetNames[0]
          const worksheet = workbook.Sheets[firstSheetName]
          const header = this.getHeaderRow(worksheet)
          const results = XLSX.utils.sheet_to_json(worksheet)
          this.generateData({ header, results })
          this.loading = false
          resolve()
        }
        reader.readAsArrayBuffer(rawFile)
      })
    },
    getHeaderRow(sheet) {
      const headers = []
      const range = XLSX.utils.decode_range(sheet['!ref'])
      let C
      const R = range.s.r
      /* start in the first row */
      for (C = range.s.c; C <= range.e.c; ++C) { /* walk every column in the range */
        const cell = sheet[XLSX.utils.encode_cell({ c: C, r: R })]
        /* find the cell in the first row */
        let hdr = 'UNKNOWN ' + C // <-- replace with your desired default
        if (cell && cell.t) hdr = XLSX.utils.format_cell(cell)
        headers.push(hdr)
      }
      return headers
    },
    isExcel(file) {
      return /\.(xlsx|xls|csv)$/.test(file.name)
    }
  }
}
</script>

<style scoped lang="scss">
.upload-excel {
  display: flex;
  justify-content: center;
   margin-top: 100px;
   .excel-upload-input{
       display: none;
        z-index: -9999;
     }
   .btn-upload , .drop{
      border: 1px dashed #bbb;
      width: 350px;
      height: 160px;
      text-align: center;
      line-height: 160px;
   }
   .drop{
       line-height: 80px;
       color: #bbb;
      i {
        font-size: 60px;
        display: block;
      }
   }
}
</style>

创建路由和组件

建立公共导入的页面路由，新建一个公共的导入页面，挂载路由 src/router/index.js

    path: '/import',
    component: Layout,
    hidden: true, // 隐藏在左侧菜单中
    children: [{
      path: '', // 二级路由path什么都不写 表示二级默认路由
      component: () => import('@/views/import')
    }]
  },

创建import路由组件 src/views/import/index.vue

<template>
  <!-- 公共导入组件 -->
  <upload-excel :on-success="success" />
</template>

实现导入

封装导入用户的api接口

export function importUser(data) {
  return request({
    url: 'user/batch',
    method: 'post',
    data
  })
}

获取导入的excel数据, 导入excel接口

 async  success({ header, results }) {
      // 如果是导入用户
        const userRelations = {
          '入职日期': 'create_time',
          '手机号': 'mobile',
          '用户名': 'username',
          '密码': 'password',
          '邮箱': 'email',
          '部门':'部门'
        }
        const arr = []
       results.forEach(item => {
          const userInfo = {}
          Object.keys(item).forEach(key => {
            userInfo[userRelations[key]] = item[key]
          })
         arr.push(userInfo)
        })
        await importUser(arr) // 调用导入接口
        this.$router.back()
    }

为了让这个页面可以服务更多的导入功能，我们可以在页面中用参数来判断，是否是导入用户

 data() {
    return {
      type: this.$route.query.type
    }
  },

当excel中有日期格式的时候，实际转化的值为一个数字，我们需要一个方法进行转化

formatDate(numb, format) {
      const time = new Date((numb - 1) * 24 * 3600000 + 1)
      time.setYear(time.getFullYear() - 70)
      const year = time.getFullYear() + ''
      const month = time.getMonth() + 1 + ''
      const date = time.getDate() - 1 + ''
      if (format && format.length === 1) {
        return year + format + month + format + date
      }
      return year + (month < 10 ? '0' + month : month) + (date < 10 ? '0' + date : date)
    }

导入的手机号不能和之前的存在的手机号重复

逻辑判断

 async  success({ header, results }) {
      if (this.type === 'user') {
        const userRelations = {
          '入职日期': 'create_time',
          '手机号': 'mobile',
          '用户名': 'username',
          '密码': 'password',
          '邮箱': 'email',
          '部门':'部门'
        }
        const arr = []
        // 遍历所有的数组
        results.forEach(item => {
        // 需要将每一个条数据里面的中文都换成英文
          const userInfo = {}
          Object.keys(item).forEach(key => {
          // key是当前的中文名 找到对应的英文名
            if (userRelations[key] === 'timeOfEntry' || userRelations[key] === 'correctionTime') {
              userInfo[userRelations[key]] = new Date(this.formatDate(item[key], '/')) // 只有这样, 才能入库
              return
            }
            userInfo[userRelations[key]] = item[key]
          })
          // 最终userInfo变成了全是英文
          arr.push(userInfo)
        })
        await importUser(arr)
        this.$message.success('导入成功')
      }
      this.$router.back() // 回到上一页
    },
    formatDate(numb, format) {
      const time = new Date((numb - 1) * 24 * 3600000 + 1)
      time.setYear(time.getFullYear() - 70)
      const year = time.getFullYear() + ''
      const month = time.getMonth() + 1 + ''
      const date = time.getDate() - 1 + ''
      if (format && format.length === 1) {
        return year + format + month + format + date
      }
      return year + (month < 10 ? '0' + month : month) + (date < 10 ? '0' + date : date)
    }

用户页面跳转

<el-button type="warning" size="small" @click="$router.push('/import?type=user')">导入</el-button>

用户导出**

日常业务中，我们经常遇到excel导出功能， 怎么使用呢
Excel 的导入导出都是依赖于js-xlsx来实现的。
在 js-xlsx的基础上又封装了Export2Excel.js来方便导出数据。

安装所需依赖

npm install xlsx file-saver -S
npm install script-loader -S -D

由于js-xlsx体积还是很大的，导出功能也不是一个非常常用的功能，所以使用的时候建议使用懒加载。使用方法如下：

import('@/vendor/Export2Excel').then(excel => {
  excel.export_json_to_excel({
    header: tHeader, //表头 必填
    data, //具体数据 必填
    filename: 'excel-list', //非必填
    autoWidth: true, //非必填
    bookType: 'xlsx' //非必填
  })
})

excel导出参数的介绍

vue-element-admin提供了导出的功能模块，在课程资源/excel导出目录下，放置到src目录下

excel导出基本的结构

下面代码会用到 Export2Excel.js 模块，所以首先在 src 目录下新建 vendor 目录，其中新建 Export2Excel.js ，输入如下代码

/* eslint-disable */
import { saveAs } from 'file-saver'
import XLSX from 'xlsx'

function generateArray(table) {
  var out = [];
  var rows = table.querySelectorAll('tr');
  var ranges = [];
  for (var R = 0; R < rows.length; ++R) {
    var outRow = [];
    var row = rows[R];
    var columns = row.querySelectorAll('td');
    for (var C = 0; C < columns.length; ++C) {
      var cell = columns[C];
      var colspan = cell.getAttribute('colspan');
      var rowspan = cell.getAttribute('rowspan');
      var cellValue = cell.innerText;
      if (cellValue !== "" && cellValue == +cellValue) cellValue = +cellValue;

      //Skip ranges
      ranges.forEach(function (range) {
        if (R >= range.s.r && R <= range.e.r && outRow.length >= range.s.c && outRow.length <= range.e.c) {
          for (var i = 0; i <= range.e.c - range.s.c; ++i) outRow.push(null);
        }
      });

      //Handle Row Span
      if (rowspan || colspan) {
        rowspan = rowspan || 1;
        colspan = colspan || 1;
        ranges.push({
          s: {
            r: R,
            c: outRow.length
          },
          e: {
            r: R + rowspan - 1,
            c: outRow.length + colspan - 1
          }
        });
      };

      //Handle Value
      outRow.push(cellValue !== "" ? cellValue : null);

      //Handle Colspan
      if (colspan)
        for (var k = 0; k < colspan - 1; ++k) outRow.push(null);
    }
    out.push(outRow);
  }
  return [out, ranges];
};

function datenum(v, date1904) {
  if (date1904) v += 1462;
  var epoch = Date.parse(v);
  return (epoch - new Date(Date.UTC(1899, 11, 30))) / (24 * 60 * 60 * 1000);
}

function sheet_from_array_of_arrays(data, opts) {
  var ws = {};
  var range = {
    s: {
      c: 10000000,
      r: 10000000
    },
    e: {
      c: 0,
      r: 0
    }
  };
  for (var R = 0; R != data.length; ++R) {
    for (var C = 0; C != data[R].length; ++C) {
      if (range.s.r > R) range.s.r = R;
      if (range.s.c > C) range.s.c = C;
      if (range.e.r < R) range.e.r = R;
      if (range.e.c < C) range.e.c = C;
      var cell = {
        v: data[R][C]
      };
      if (cell.v == null) continue;
      var cell_ref = XLSX.utils.encode_cell({
        c: C,
        r: R
      });

      if (typeof cell.v === 'number') cell.t = 'n';
      else if (typeof cell.v === 'boolean') cell.t = 'b';
      else if (cell.v instanceof Date) {
        cell.t = 'n';
        cell.z = XLSX.SSF._table[14];
        cell.v = datenum(cell.v);
      } else cell.t = 's';

      ws[cell_ref] = cell;
    }
  }
  if (range.s.c < 10000000) ws['!ref'] = XLSX.utils.encode_range(range);
  return ws;
}

function Workbook() {
  if (!(this instanceof Workbook)) return new Workbook();
  this.SheetNames = [];
  this.Sheets = {};
}

function s2ab(s) {
  var buf = new ArrayBuffer(s.length);
  var view = new Uint8Array(buf);
  for (var i = 0; i != s.length; ++i) view[i] = s.charCodeAt(i) & 0xFF;
  return buf;
}

export function export_table_to_excel(id) {
  var theTable = document.getElementById(id);
  var oo = generateArray(theTable);
  var ranges = oo[1];

  /* original data */
  var data = oo[0];
  var ws_name = "SheetJS";

  var wb = new Workbook(),
    ws = sheet_from_array_of_arrays(data);

  /* add ranges to worksheet */
  // ws['!cols'] = ['apple', 'banan'];
  ws['!merges'] = ranges;

  /* add worksheet to workbook */
  wb.SheetNames.push(ws_name);
  wb.Sheets[ws_name] = ws;

  var wbout = XLSX.write(wb, {
    bookType: 'xlsx',
    bookSST: false,
    type: 'binary'
  });

  saveAs(new Blob([s2ab(wbout)], {
    type: "application/octet-stream"
  }), "test.xlsx")
}

export function export_json_to_excel({
  multiHeader = [],
  header,
  data,
  filename,
  merges = [],
  autoWidth = true,
  bookType = 'xlsx'
} = {}) {
  /* original data */
  filename = filename || 'excel-list'
  data = [...data]
  data.unshift(header);

  for (let i = multiHeader.length - 1; i > -1; i--) {
    data.unshift(multiHeader[i])
  }

  var ws_name = "SheetJS";
  var wb = new Workbook(),
    ws = sheet_from_array_of_arrays(data);

  if (merges.length > 0) {
    if (!ws['!merges']) ws['!merges'] = [];
    merges.forEach(item => {
      ws['!merges'].push(XLSX.utils.decode_range(item))
    })
  }

  if (autoWidth) {
    /*设置worksheet每列的最大宽度*/
    const colWidth = data.map(row => row.map(val => {
      /*先判断是否为null/undefined*/
      if (val == null) {
        return {
          'wch': 10
        };
      }
      /*再判断是否为中文*/
      else if (val.toString().charCodeAt(0) > 255) {
        return {
          'wch': val.toString().length * 2
        };
      } else {
        return {
          'wch': val.toString().length
        };
      }
    }))
    /*以第一行为初始值*/
    let result = colWidth[0];
    for (let i = 1; i < colWidth.length; i++) {
      for (let j = 0; j < colWidth[i].length; j++) {
        if (result[j]['wch'] < colWidth[i][j]['wch']) {
          result[j]['wch'] = colWidth[i][j]['wch'];
        }
      }
    }
    ws['!cols'] = result;
  }

  /* add worksheet to workbook */
  wb.SheetNames.push(ws_name);
  wb.Sheets[ws_name] = ws;

  var wbout = XLSX.write(wb, {
    bookType: bookType,
    bookSST: false,
    type: 'binary'
  });
  saveAs(new Blob([s2ab(wbout)], {
    type: "application/octet-stream"
  }), `${filename}.${bookType}`);
}

因为数据中的key是英文，想要导出的表头是中文的话，需要将中文和英文做对应

 const headers = {
        '入职日期': 'create_time',
        '手机号': 'mobile',
        '用户名': 'username',
        '角色': 'role_name',
        '邮箱': 'email',
        '部门': 'department_name'
      }

完成导出代码

import { formatDate } from '@/filters'
// 导出数据
    exportData() {
      const headers = {
        '入职日期': 'create_time',
        '手机号': 'mobile',
        '用户名': 'username',
        '角色': 'role_name',
        '邮箱': 'email',
        '部门': 'department_name'
      }
      import('@/vendor/Export2Excel').then(async excel => {
        const res = await getUserList({ query: '', pagenum: 1, pagesize: this.page.total })
        // console.log(res)
        const data = this.formatJson(headers, res.users)
        console.log(data)
        excel.export_json_to_excel({
          header: Object.keys(headers),
          data,
          filename: '用户信息表',
          autoWidth: true,
          bookType: 'xlsx'

        })
      })
    }
    }

导出时间格式的处理

   // 该方法负责将数组转化成二维数组
    formatJson(headers, rows) {
      return rows.map(item => {
        return Object.keys(headers).map(key => {
          if (headers[key] === 'create_time') {
            return formatDate(item[headers[key]]) // formatDate 函数是定义好的一个过滤器
          }
          return item[headers[key]]
        })
      })

过滤器 formatDate

import moment from 'moment'
export function formatTime(value) {
  return moment(value * 1000).format('YYYY-MM-DD HH:mm:ss')
}
export function formatDate(value) {
  return moment(value * 1000).format('YYYY-MM-DD')
}

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