vue+element+springboot实现文件下载进度条展现功能示例

<!--下载进度条-->
    <el-dialog title="正在下载，请等待" :visible.sync="fileDown.loadDialogStatus" :close-on-click-modal="false" 
      :close-on-press-escape="false" :show-close="false" width="20%">
      <div style="text-align: center;">
        <el-progress type="circle" :percentage="fileDown.percentage"></el-progress>
      </div>
      <div slot="footer" class="dialog-footer">
        <el-button type="primary" @click="downClose">取消下载</el-button>
      </div>  
    </el-dialog>

fileDown: {
        loadDialogStatus: false, //弹出框控制的状态
        percentage: 0, //进度条的百分比
        source: {}, //取消下载时的资源对象
      },

downFile(row) {
    //这里放参数
    var param = {};
    this.fileDown.loadDialogStatus = true;
    this.fileDown.percentage = 0;
    const instance = this.initInstance();
    instance({
        method: "post",
        withCredentials: true,
        url: "替换下载地址",
        params: param,
        responseType: "blob"
    }).then(res => {
        this.fileDown.loadDialogStatus = false;
        console.info(res);
        const content = res.data;
        if (content.size == 0) {
          this.loadClose();
          this.$alert("下载失败");
          return ;
        }
        const blob = new Blob([content]);
        const fileName = row.fileName;//替换文件名
        if ("download" in document.createElement("a")) {
          // 非IE下载
          const elink = document.createElement("a");
          elink.download = fileName;
          elink.style.display = "none";
          elink.href = URL.createObjectURL(blob);
          document.body.appendChild(elink);
          elink.click();
          setTimeout(function() {
            URL.revokeObjectURL(elink.href); // 释放URL 对象
            document.body.removeChild(elink);
          }, 100);
        } else {
          // IE10+下载
          navigator.msSaveBlob(blob, fileName);
        }
      }).catch(error => {
          this.fileDown.loadDialogStatus = false;
          console.info(error);
      });
  },
initInstance() {
      var _this = this;
      //取消时的资源标记
      this.fileDown.source = axiOS.CancelToken.source();
      const instance = axios.create({ //axios 这个对象要提前导入 或者替换为你们全局定义的
        onDownloadProgress: function(ProgressEvent) {
          const load = ProgressEvent.loaded;
          const total = ProgressEvent.total;
          const progress = (load / total) * 100;
          console.log('progress='+progress);
          //一开始已经在计算了 这里要超过先前的计算才能继续往下
          if (progress > _this.fileDown.percentage) {
            _this.fileDown.percentage = Math.floor(progress);
          }
          if(progress == 100){
            //下载完成
            _this.fileDown.loadDialogStatus = false;
          }
        },
        cancelToken: this.fileDown.source.token,//声明一个取消请求token
      });
      return instance;
    },
    downClose() {
      //中断下载
      this.$confirm("点击关闭后将中断下载，是否确定关闭？", this.$t("button.tip"), {
        confirmButtonText: this.$t("button.confirm"),
        cancelButtonText: this.$t("button.cancel"),
        type: "warning"
      }).then(() => {
          //中断下载回调
          this.fileDown.source.cancel('log==客户手动取消下载');
      }).catch(() => {
          //取消--什么都不做
      });      
    },

//获取本地文件 并计算大小
File file = new File(zipFileName);//读取压缩文件
InputStream inputStream = new FileInputStream(file);
int totalSize = inputStream.available(); //获取文件大小
logger.info("压缩后===当前文件下载大小size={}", totalSize);
response.setHeader("Content-Length", totalSize+"");//这里注意 一定要在response.getOutputStream()之前就把这个setHeader属性设进去，否则也不生效
OutputStream out = response.getOutputStream();
后续省略.....