excel表的导入导出

excel表的导入:

上传excel文件，把excel文件的内容读出来，还原成最基本的行列结构，按后端的接口要求回传过去

通过名为xlsx的插件实现对excel表的导入

1.安装插件

npm install xlsx -S
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2.创建名为UploadExcel/index.vue的文件,并注册为全局组件

<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 // 提示文本
      <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' // 引入安装的插件xlsx

export default {
  props: { // 需要传入的函数
    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() // 阻止默认行为
      if (this.loading) return
      const files = e.dataTransfer.files
      if (files.length !== 1) { // 文件长度不等于1
        this.$message.error('Only support uploading one file!') // 提示信息 只支持上传一个文件
        return
      }
      const rawFile = files[0] // only use files[0] 使用上传的文件

      if (!this.isExcel(rawFile)) { // 检查文件是否为excel表
        this.$message.error('Only supports upload .xlsx, .xls, .csv suffix files')
        return false
      }
      this.upload(rawFile) // 通过层层筛选最终确认上传的文件格式正确并上传
      e.stopPropagation()
      e.preventDefault()
    },
    handleDragover(e) {
      e.stopPropagation()
      e.preventDefault()
      e.dataTransfer.dropEffect = 'copy'
    },
    handleUpload() {
      this.$refs['excel-upload-input'].click() // 点击按钮 调用隐藏的 input 进行文件上传
    },
    handleClick(e) { // input 点击事件
      const files = e.target.files
      const rawFile = files[0] // only use files[0]
      if (!rawFile) return // 如果为空return
      this.upload(rawFile) // 不为空上传
    },
    upload(rawFile) { // 对上传的文件进行处理
      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) // 读取文件
      }
    },
    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) { // 对文件名正则验证方法
      return /\.(xlsx|xls|csv)$/.test(file.name)
    }
  }
}
</script>
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3.引入UploadExcel组件并注册为全局

import Vue from 'vue'
import UploadExcel from '@/components/UploadExcel'

const Tools = {
  install(Vue) {
    Vue.component('UploadExcel', UploadExcel)
  }
}
Vue.use(Tools)

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如果单独开页面注册要将其引入main.js文件中

4.使用组件

<template>
  <upload-excel :on-success="handleSuccess" /> 
  <!-- 调用组件需要传入一个接收成功信息的回调函数 -->
</template>

methods: {   //  ↓{ header, results }为解构赋值写法 实际形参是一个对象
    handleSuccess({ header, results }) { // 回调函数,数据上传成功后的结果
    //   console.log(header)
    //   console.log(results)表中数据处理后的结果,[{},{}]格式
    },
}

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该插件会将excel表中的日期格式数据转换为一串数字,需要将其转换

// 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)
}
特定文件中导出,在使用的文件中将该方法引入,对转换为数字的日期格式进行还原
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导出为excel表

同样需要安装依赖的插件

npm install xlsx -S
npm install file-saver script-loader  
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创建文件src/vendor/Export2Excel.js

/* 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")
}
// 使用了此方法  ↓
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}`);
}

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使用

在需要的页面定义触发按钮,引入创建的文件
// 导出按钮
    exportExcel() {
      // 按需导出
      import('@/vendor/Export2Excel').then(excel => { // 懒加载,只有点击时才会引入文件
        // excel表示导入的模块对象
        console.log(excel)
        excel.export_json_to_excel({
          header: ['姓名', '工资'], // 表头 必填  
          data: [
            ['刘备', 100],
            ['关羽', 500]
          ], // 具体数据 必填   通过修改header与data属性实现导出指定样式的Excel表格
          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
        })
      })
    }
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导出后的文件如下