如何在项目中实现excel导入导出功能

前言

在项目中我们通常需要添加数据,少量数据我们可以一条一条添加,但是一旦添加数据的量比较大,这样的操作效率就会很低,因此我们需要批量导入功能.同理我们导出大量的数据单靠一行行的cv效率也是非常低的,因此也需要一个批量导出功能.

实现excel导入功能

1.安装必要插件

npm install xlsx -S

2.在src/components/UploadExcel下创建UploadExcel.vue组件

本文是将vue-element-admin提供的组件复制到src/components/UploadExcel下,以下是vue-element-admin提供的组件代码:

<template>
  <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">
      Drop excel file here or
      <el-button :loading="loading" style="margin-left:16px;" size="mini" type="primary" @click="handleUpload">
        Browse
      </el-button>
    </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>
.excel-upload-input{
  display: none;
  z-index: -9999;
}
.drop{
  border: 2px dashed #bbb;
  width: 600px;
  height: 160px;
  line-height: 160px;
  margin: 0 auto;
  font-size: 24px;
  border-radius: 5px;
  text-align: center;
  color: #bbb;
  position: relative;
}
</style>

3.在src/components下的index.js中注册为全局组件

import uploadExcel from './UploadExcel'

export default {
  // 插件的初始化, 插件给你提供的全局的功能, 都可以在这里配置
  install(Vue) {
    // 进行组件的全局注册
    省略其他代码....
    Vue.component('uploadExcel', uploadExcel) // 注册导入excel组件
  }
}

4.在src/views/employees/import下新建index.vue

<template>
  <uploadExcel :on-success="handleSuccess" />
</template>

<script>
export default {
  name: 'Import',
  methods: {
    handleSuccess({ header, results }) {
      console.log(header, results)
    }
  }
}
</script>

5.配置路由权限

在employees.js文件中配置路由

6.在src/views/employees/import/index.vue文件新增方法

import { formatExcelDate } from '@/utils/index.js'

// 将[{'姓名'：'小张'， '手机号': '13712345678'}, {.....}]转换为[ {'username'：'小张'，'mobile': '13712345678'}, {.....} ],即把一个对象数组中的每个对象的属性名，从中文改成英文
// 思路：对于原数组每个对象来说
//    （1） 找出所有的中文key
//     (2)  得到对应的英文key
//     (3)  拼接一个新对象： 英文key:值
    transExcel(results) {
      const mapInfo = {
        '入职日期': 'timeOfEntry',
        '手机号': 'mobile',
        '姓名': 'username',
        '转正日期': 'correctionTime',
        '工号': 'workNumber',
        '部门': 'departmentName',
        '聘用形式': 'formOfEmployment'
      }
      return results.map(zhObj => {
        const enObj = {}
        const zhKeys = Object.keys(zhObj) // ['姓名', '手机号']

        zhKeys.forEach(zhKey => {
          const enKey = mapInfo[zhKey]
          // 只有入职时间和转正时间需要处理
      if (enKey === 'timeOfEntry' || enKey === 'correctionTime') {
            // 后端需要的日期格式是标准时间
          enObj[enKey] = new Date(formatExcelDate(zhObj[zhKey]))
          } else {
            enObj[enKey] = zhObj[zhKey]
          }
        })

        return enObj
      })
    }

7.在utils/index.js文件下新增方法如下:

因为excel内部进行特殊的编码,会让从excel中读入的时间"变形"

// 把excel文件中的日期格式的内容转回成标准时间
// https://blog.csdn.net/qq_15054679/article/details/107712966
export function formatExcelDate(numb, format = '/') {
  const time = new Date((numb - 25567) * 24 * 3600000 - 5 * 60 * 1000 - 43 * 1000 - 24 * 3600000 - 8 * 3600000)
  time.setYear(time.getFullYear())
  const year = time.getFullYear() + ''
  const month = time.getMonth() + 1 + ''
  const date = time.getDate() + ''
  if (format && format.length === 1) {
    return year + format + month + format + date
  }
  return year + (month < 10 ? '0' + month : month) + (date < 10 ? '0' + date : date)
}

8.在src/api/employee.js文件中准备接口

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

9.在页面中使用

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

async doImport(data) {
      try {
        const res = await importEmployee(data)
        console.log('importEmployee', res)
        this.$message.success('导入成功')

        // 页面后退
        this.$router.back()
      } catch (err) {
        console.log('importEmployee', err)
        this.$message.error('导入失败')
      }
    },
    //  1. 把数据从excel文件读入到浏览器内存
    handleSuccess({ header, results }) {
      console.log(header, results)

      // 2. 按接口要求 组装数据
      const data = this.transExcel(results)
      console.log('按接口要求 组装数据', data)
      // 3. 调用接口做上传
      this.doImport(data)
    }

实现excel导出功能

1.安装依赖

npm install file-saver script-loader xlsx --save

2.在src/vendor文件下新建export2Excel.js文件

本文是将vue-element-admin提供的文件复制到src/vendor下,以下是vue-element-admin提供的组件代码:

/* 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}`);
}

3.在src/view/employees/Employees.vue中新增方法

formatData(list) {
      const map = {
        'id': '编号',
        'password': '密码',
        'mobile': '手机号',
        'username': '姓名',
        'timeOfEntry': '入职日期',
        'formOfEmployment': '聘用形式',
        'correctionTime': '转正日期',
        'workNumber': '工号',
        'departmentName': '部门',
        'staffPhoto': '头像地址'
      }
      console.log(list)
      let header = []
      // header = ['id', 'mobile', 'username', .....]
      // data = [
      //     ['65c2', '1380000002', '管理员', ....],
      //     ['65c3', '1380000003', '孙财', ....],
      // ]
      let data = []
      // 开始代码
      // 找到一个元素
      const one = list[0]
      // 用于判断是否有数据
      if (!one) {
        return { header, data }
      }
      header = Object.keys(one).map(key => {
        return map[key]
      })

      // data把list中每一个对象转成 对应的value数组
      data = list.map(obj => {
        // 把  Obj['formOfEmployment']: 1 , 2   ---> '正式'， '非正式'
        const key = obj['formOfEmployment'] // 1, 2
        obj['formOfEmployment'] =this.hireType[key] // hireType:{1:'正式', '2':'非正式' }

        return Object.values(obj)
      })

      return { header, data }
    },
    hExport() {
      import('@/vendor/Export2Excel').then(async excel => {
        // 发ajax请求，获取数据
        const res = await getEmployee(this.page, this.size)
        const list = res.data.rows
        console.log('从后端获取的数据', list)

        const { header, data } = this.formatData(list)
        // excel表示导入的模块对象
        console.log(header, data)
        excel.export_json_to_excel({
          // header: ['姓名', '工资'], // 表头 必填
          header: header, // 表头 必填
          data: data,
          // data: [
          //   ['刘备11111111111111', 100],
          //   ['关羽', 500]
          // ], // 具体数据 必填
          filename: 'excel-list', // 文件名称
          autoWidth: true, // 宽度是否自适应
          bookType: 'xlsx' // 生成的文件类型
        })
      })
    }

最后

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