VUE导出excel表格

本来想直接白嫖文档demo和大佬博客的demo，发现白嫖失败，于是写下自己踩坑过程

安装命令

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

在src下新建立一个verdor文件夹

在verdor下新建Export2Excel.js文件
Export2Excel.js内容如下

/* 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}`);
}

使用

直接在你的methods下面粘贴这两个方法handleDownload 、 formatJson。

    handleDownload() {
    //downloadLoading是elementui自带的效果，在data里面初始化为downloadLoading: false
    //如果想用可以看下面的button代码介绍
      this.downloadLoading = true
      import('@/vendor/Export2Excel').then(excel => {
        const tHeader = ['序号', '姓名', '学号', '性别', '年级','班级','职务']
        const filterVal = ['id','name', 'studentid', 'gender', 'grade','classname','post']
        const list = this.list
        //这个list是我的data里面的数据，我后端返回的是一个ArrayList对象
        const data = this.formatJson(filterVal, list)
        excel.export_json_to_excel({
          header: tHeader,
          data,
          filename: 'student_table',
          autoWidth: this.autoWidth,
          bookType: this.bookType
        })
        this.downloadLoading = false
      })
    },
    formatJson(filterVal, jsonData) {
      return jsonData.map(v => filterVal.map(j => {
        if (j === 'timestamp') {
          return parseTime(v[j])
        } else {
          return v[j]
        }
      }))
    }

介绍一下handleDownload 里面几个参数（重点）：
tHeader 就是你表格的表头
比如我的是

const tHeader = ['序号', '姓名', '学号', '性别', '年级','班级','职务']

效果就是如下图所示

filterVal 对应的是你的list字面的key
这个list是我的data里面的数据，我后端返回的是一个ArrayList对象，list

其他的就直接看官方的表格介绍吧

最后偷懒可以直接用现成的button，button代码都不用写了（downloadLoading是elementui自带的效果，在data里面初始化为downloadLoading: false）

 <el-button :loading="downloadLoading" style="margin:0 0 20px 20px;" type="primary" icon="el-icon-document" @click="handleDownload">
            导出表格
          </el-button>

到这里就结束啦，下面还有一种导出已选择项的补充

(进阶)导出已选择项

效果图，在最左侧多了一列选择框，只导出已经勾选的内容

新增代码

在el-table的定义下面新增 ref=“multipleTable” 与 @selection-change=“handleSelectionChange”

<el-table
   ref="multipleTable"
   v-loading="listLoading"
   :data="list"
   fit
   border
   @selection-change="handleSelectionChange"
        >
//新增加一列勾选框
<el-table-column type="selection" align="center" />

新增data

data() {
    return {
      multipleSelection: [],
      downloadLoading: false,
      list: [],
    }
  },

新增方法

  handleSelectionChange(val) {
      this.multipleSelection = val
    },

handleDownload改动

改动的地方如下

代码：

handleDownload() {
      if (this.multipleSelection.length) {
        this.downloadLoading = true
        import('@/vendor/Export2Excel').then(excel => {
          const tHeader = ['序号', '姓名', '学号', '性别', '年级', '班级', '职务']
          const filterVal = ['id', 'name', 'studentid', 'gender', 'grade', 'classname', 'post']
          const list = this.multipleSelection
          const data = this.formatJson(filterVal, list)
          excel.export_json_to_excel({
            header: tHeader,
            data,
            filename: 'student_table',
            autoWidth: this.autoWidth,
            bookType: this.bookType
          })
          this.downloadLoading = false
        })
      }else {
        this.$message({
          message: '请先选择要导出的内容',
          type: 'warning'
        })
      }
    }

over