一、导入

2.1 安装xlsx插件

$ npm i xlsx@0.17.0

2.2 新建导入功能组件

新建组件 UploadExcel/index.vue

<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>

2.3 注册全局的导入excel组件

src\components\index.js

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

2.4 创建导入路由组件

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

2.5 封装导入接口 实现excel导入

import { importEmployee } from '@/api/employees'

// 在methods中修改success函数
async  success({ header, results }) {
      // 如果是导入员工
        const userRelations = {
          '入职日期': 'timeOfEntry',
          '手机号': 'mobile',
          '姓名': 'username',
          '转正日期': 'correctionTime',
          '工号': 'workNumber'
        }
       // const arr = []
      // results.forEach(item => {
      //   const userInfo = {}
      //   Object.keys(item).forEach(key => {
      //     userInfo[userRelations[key]] = item[key]
      //   })
      //   arr.push(userInfo)
      // })
      // await importEmployee(arr) // 调用导入接口
      // map 函数 通过指定函数处理数组的每个元素，并返回处理后的数组。
      // map() 方法返回一个新数组，数组中的元素为原始数组元素调用函数处理后的值
      var newArr = results.map(item => {
        var userInfo = {}
        Object.keys(item).forEach(key => {
          userInfo[userRelations[key]] = item[key]
        })
        return userInfo
      })
      await importEmployee(newArr) // 调用导入接口
      this.$message.success('导入excel成功')
      this.$router.back() // 回到上一个页面
    }

2.6 导入时间格式的处理

定义事件处理方法 调用此方法

    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)
    }

二、导出

2.1 安装excel所需依赖和按需加载

npm install xlsx@0.17.0 file-saver -S
npm install script-loader -S -D

2.2 vue-element-admin提供的导出功能模块

Export2Excel.js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}`);
}

2.3 懒加载引入js-xlsx

// 导出excel按钮方法
 async toExcel() {
  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', //excel名称
      autoWidth: true, // 是否自适应
      bookType: 'xlsx', // 导出格式
    })
  })
}

excel导出参数的介绍

2.4 导出数据结构的处理

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

// 导出excel
    async toExcel() {
      const headers = {
        '姓名': 'username',
        '手机号': 'mobile',
        '入职日期': 'timeOfEntry',
        '聘用形式': 'formOfEmployment',
        '转正日期': 'correctionTime',
        '工号': 'workNumber',
        '部门': 'departmentName'
      }
      // 获取接口中的全部数据
      const { rows } = await getEmployeeList({ page: 1, size: this.page.total })
      console.log('打印rows', rows)
      // 调用数据处理方法
      const data = this.formatJson(headers, rows)
      // 懒加载  只有点击的时候才导入
      import('@/vendor/Export2Excel').then(excel => {
        // console.log('导出', excel)
        excel.export_json_to_excel({
          header: Object.keys(headers), // 表头
          data: data, // 数据
          filename: '员工信息表', // 表格名称
          autoWidth: true, // 是否自适应
          bookType: 'xlsx', // 导出格式
        })
      })
    },
    // 数组转成二维数组[[]]
    formatJson(headers, list) {
      console.log('1111', headers, list)
      return list.map((item) => {
        return Object.keys(headers).map(key => {
          if (headers[key] === 'timeOfEntry' || headers[key] === 'correctionTime') {
            // 时间的处理
            return formatDate(item[headers[key]])
          } else if (headers[key] === 'formOfEmployment') {
            // 聘用形式的处理   find返回当前找到的对象
            const obj = EmployeeEnum.hireType.find(obj => obj.id === item[headers[key]])
            return obj ? obj.value : '未知'
          }
          return item[headers[key]]
        })
      })
    }

2.5 复杂表头的实现

vue-element-admin 提供的导出方法中有 multiHeader和merges 的参数

 		const multiHeader = [['姓名', '主要信息', '', '', '', '', '部门']]
        const merges = ['A1:A2', 'B1:F1', 'G1:G2']
        excel.export_json_to_excel({
          header: Object.keys(headers),
          data,
          filename: '员工资料表',
          multiHeader, // 复杂表头
          merges // 合并选项
        })