vue-element-admin项目导入和导出的实现

Arce

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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