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前端文件上传与下载(含 base64流文件)

前端文件上传与下载(含 base64流文件)

作者: oNexiaoyao | 来源:发表于2020-06-06 21:35 被阅读0次

    上传文件实现

    • elementUi el-upload + axios

      自定义上传实现:

      /**
      * 批量上传文件
      * @param {*} param
      */
      export function uploadFile(param, fileInfo) {
          return request({
              method: 'post',
              url: `document/hdfs/up`,
              data: param,
              onUploadProgress: (progressEvent) => {
              let num = progressEvent.loaded / progressEvent.total * 100 | 0;  //百分比
              fileInfo.onProgress({percent: num})     //进度条
              }
          });
      }
      
      <el-upload
      ref="upload"
      action=""
      :http-request="handleCustomUpload"
      :on-preview="handleFilePreview"
      :on-remove="handleFileUploadRemove"
      :on-success="handleFileUploadSuccess"
      :before-upload="handleFileBeforeUpload"
      :file-list="docDialogForm.fileList"
      :multiple="docDialogMode === '批量上传' ? true : false"
      :auto-upload="true"
      >
      
      // 自定义上传
      handleCustomUpload(fileInfo) {
        let file = fileInfo.file;
        this.handleUploadFile(file, fileInfo);
      },
      handleUploadFile(file, fileInfo) {
        // 执行具体上传代码
        let uploadFile = new FormData();
        uploadFile.append('file', file);
        let self = this;
        http.uploadFile(uploadFile, fileInfo)
        .then(res => {
          // 上传成功(打钩的小图标)
          fileInfo.onSuccess();
          if (res.items && (this.docDialogMode === '新增' || this.docDialogMode === '编辑' )) {
            self.docDialogForm.storagePath = res.items[0].storagePath;
            self.docDialogForm.name = res.items[0].name;
            self.docDialogForm.extension = res.items[0].name.slice(res.items[0].name.lastIndexOf('.') + 1);
          }
          if (res.items && this.docDialogMode === '批量上传') {
            self.docDialogForm.batchUploadFileInfo.push({
              name: res.items[0].name,
              storagePath: res.items[0].storagePath,
              extension: res.items[0].name.slice(res.items[0].name.lastIndexOf('.') + 1),
              uid: fileInfo.file.uid
            });
          }
        })
        .catch(() => {
          console.log('文件上传失败');
        })
      }
      
      function updateFile() {
          var fileInput = document.getElementById("selectFile");
          if(fileInput.files[0] == undefined){
              return;
          }
          var file = fileInput.files[0];
          //FileReader可直接将上传文件转化为二进制流
          var reader = new FileReader();  
          reader.readAsDataURL(file);//转化二进制流,异步方法
          reader.onload = function(){//完成后this.result为二进制流
              var base64Str = this.result;
              var startNum = base64Str.indexOf("base64,");
              startNum = startNum*1 + 7;
              //去除前部格式信息(如果有需求)
              var baseStr = base64Str.slice(startNum);
          }
      }
      

    下载实现

    • 接口直接返回资源的访问路径

      直接利用 <a> 标签下载

      // 创建下载链接并开始下载
      function createDownloadUrl(Url) {
          const a = document.createElement('a');
          a.style.display = 'none';
          a.download = '测试';
          a.href = Url;
          a.click();
          document.body.removeChild(a);
      }
      
    • 接口返回二进制文件流

      • 使用 axios 下载

        下载接口:

        /**
        * 下载文档
        * @param {*} param
        */
        export function downloadFile(documentCode) {
            return request({
                method: 'post',
                url: `document/hdfs/down?documentCode=${documentCode}`,
                responseType: 'blob'
            });
        }
        

        下载具体实现:

        handleRowDownload(scope) {
            // 表格行下载
            http.downloadFile(scope.row.code)
            .then(res => {
                const blob = new Blob([res]);
                // 某些情况下需要明确下载的文件类型
                // const blob = new Blob([res], {type: "application/zip"});
                const a = document.createElement('a');
                a.download = scope.row.name;
                a.href = window.URL.createObjectURL(blob);
                a.click();
            })
            .catch(() => {
                this.$message.error('下载文档失败');
            })
        }
        

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        本文标题:前端文件上传与下载(含 base64流文件)

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