恰逢项目中要实现excel表格上传，度娘甚久，得此一文，留之。 原文：https://blog.csdn.net/qq_36718999/article/details/95387542

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需求

vue-cli 搭建前端项目，并使用element-ui实现本地excel表格上传。 (1) 限制上传文件只能是 xls、xlsx格式； (2) 限制上传文件大小不能超过 2MB!

图示

代码实现

  <el-form 
        ref="newUploadForm" 
        :model="newUploadForm" 
        :rules="formRules"
        label-width="140px" 
        label-position="right">
            <el-row class="mb-4">
                <el-col :span="24">
                    <el-form-item label="文件密码" prop="password" >
                        <el-input v-model="newUploadForm.password" clearable 
                        placeholder="文件密码(至少6位字母或数字)"  ></el-input>
                    </el-form-item>
                </el-col>
            </el-row>
            <el-row >
                <el-col :span="19">
                    <el-form-item label="上传文件" prop="fileName">
                        <el-input v-model="fileName" 
                        :readonly='true'
                        placeholder="文件名"
                        style="width:510px;"></el-input>
                    </el-form-item>
                </el-col>
                <el-col :span="4">
                    <el-upload
                    class="upload-demo"
                    ref="upload"
                    action="doUpload"
                    :limit="1"
                    :file-list="fileList"
                    :before-upload="beforeUpload"
                    >
                    <el-button slot="trigger"  type="primary" plain>选取文件</el-button>
                    <!-- <div slot="tip" class="el-upload__tip">只能上传excel文件，且不超过100MB</div>
                    <div slot="tip" class="el-upload-list__item-name">{{fileName}}</div> -->
                    </el-upload> 
                </el-col>
            </el-row>
            <el-row>
                <el-col :span="24">
                    <div class="btns-center mb-48 pt-48">
                        <el-button  @click="handleClose">取 消</el-button>
                        <el-button type="primary"   
                        @click="submitUpload()">确 定</el-button>
                    </div>
                </el-col>
            </el-row>
        </el-form>

  export default {
    data() {
        return {
            fileList:[],
            fileName:'', 
            newUploadForm:{
                password:'',
                fileName:''
            },
            formRules:{ // 表单 校验
                password:{required:true, trigger: 'blur',validator: validateFilePassword},
            },
        }
    },
    methods:{
        beforeUpload(file){ // 上传前 文件校验
            this.files = file;
            const extension = file.name.split('.')[1] === 'xls'
            const extension2 = file.name.split('.')[1] === 'xlsx'
            const isLt2M = file.size / 1024 / 1024 < 2
            if (!extension && !extension2) {
              this.$message.warning('上传文件只能是 xls、xlsx格式!')
              return
            }
            if (!isLt2M) {
              this.$message.warning('上传文件大小不能超过 2MB!')
              return
            }
            this.fileName = file.name;
            return false // 返回false不会自动上传
      },
      submitUpload() { // 确认上传
        this.$refs['newUploadForm'].validate(valid => { // 是否通过 表单验证
            if(valid){
                if(this.fileName == ""){
                    this.$message({
                        message:'请选择要上传的文件！',
                        type:'warning',
                        showClose:true
                    })
                    return false;
                }

                let fileFormData = new FormData();
                fileFormData.append('file', this.files, this.fileName);  // 上传的文件
                fileFormData.append('period', this.newUploadForm.password); // 文件密码
                fileFormData.append('fileName', this.newUploadForm.fileName); // 文件名

                uploadEmployee(fileFormData).then(res => { // 上传请求
                    this.fileName = '';
                    // console.log(res)
                    if(res.code == 200){

                    }else{
                    }
                }).catch(err => {
                    this.fileName = '';
                    console.log('err')
                })
            }else{
                this.$message({
                    type:'warning',
                    message:'新增条件有误！',
                    showClose:true
                })
            }
        })
      },
      handleClose() {
          this.fileName = '';
      }
    }
}

  // 上传接口  
export function uploadEmployee(params) {
    return request({
      url: '/apis/upload/uploadEmployee',
      method: 'post',
      headers: {
        'Content-Type': 'multipart/form-data'
        },
      processData: false,
      data:params
    })
  }