Vue如何实现文件预览和下载功能的前端上传组件

<template>
  <div>
    <el-upload
      v-model:file-list="fileList"
      action="你的上传地址"
      :on-success="handleFileSuccess"
      :on-remove="handleFileRemove"
      :on-error="handleFileError"
      :limit="10"
      :data="fileFormData"
      name="files"
      :on-preview="openFile"
    >
      <el-button type="primary">点击上传</el-button>
    </el-upload>
  </div>
</template>

<script>
import axios from 'axios';

export default {
  data() {
    return {
      fileList: [], // 上传文件列表
      fileFormData: {}, // 额外的上传参数，如果需要的话
      imageExtensions: ["jpg", "jpeg", "png", "gif", "bmp"], // 图片格式后缀
    };
  },
  methods: {
    async openFile(file) {
      try {
        const response = await axios.get(`/bbjApi/system/systemfile/${file.id}`, {
          responseType: "blob", // 设置响应类型为 blob
        });
        const blob = new Blob([response.data], {
          type: response.headers["content-type"],
        });
        const url = window.URL.createObjectURL(blob);

        // 根据文件类型设置预览方式
        const lowerCaseInput = file.name.toLowerCase();
        if (this.imageExtensions.some((ext) => lowerCaseInput.endsWith("." + ext))) {
          // 如果是图片类型，创建弹窗进行预览
          this.createImageModal(url);
        } else {
          // 其他类型的文件直接下载
          this.downloadFile(url, file.name);
          window.URL.revokeObjectURL(url); // 释放对象 URL
        }

      } catch (error) {
        this.$message.error("打开文件异常，请联系管理员");
      }
    },
    createImageModal(url) {
      // 创建弹窗容器
      const modalContainer = document.createElement("div");
      modalContainer.style.position = "fixed";
      modalContainer.style.top = "0";
      modalContainer.style.left = "0";
      modalContainer.style.width = "100%";
      modalContainer.style.height = "100%";
      modalContainer.style.backgroundColor = "rgba(0, 0, 0, 0.7)";
      modalContainer.style.zIndex = "9999";
      modalContainer.style.display = "flex";
      modalContainer.style.justifyContent = "center";
      modalContainer.style.alignItems = "center";

      // 创建图片元素
      const imgElement = document.createElement("img");
      imgElement.src = url;
      imgElement.style.maxWidth = "80%";
      imgElement.style.maxHeight = "80%";

      // 创建关闭按钮
      const closeButton = document.createElement("button");
      closeButton.textContent = "关闭";
      closeButton.style.position = "absolute";
      closeButton.style.top = "10px";
      closeButton.style.right = "10px";
      closeButton.style.padding = "5px 10px";
      closeButton.style.backgroundColor = "#409EFF";
      closeButton.style.border = "none";
      closeButton.style.cursor = "pointer";
      closeButton.style.borderRadius = "10px";
      closeButton.style.color = "#fff";

      // 点击关闭按钮时移除弹窗
      closeButton.addEventListener("click", () => {
        document.body.removeChild(modalContainer);
        window.URL.revokeObjectURL(url); // 释放对象 URL
      });

      // 将图片和关闭按钮添加到弹窗容器中
      modalContainer.appendChild(imgElement);
      modalContainer.appendChild(closeButton);

      // 将弹窗容器添加到页面主体中
      document.body.appendChild(modalContainer);
    },
    downloadFile(url, fileName) {
      // 创建下载链接
      const link = document.createElement("a");
      link.href = url;
      link.setAttribute("download", fileName);
      document.body.appendChild(link);
      link.click();
      document.body.removeChild(link);
    },
    handleFileSuccess(response, file, fileList) {
      // 处理文件上传成功的回调
      console.log("文件上传成功", response);
    },
    handleFileRemove(file, fileList) {
      // 处理文件移除的回调
      console.log("文件移除", file);
    },
    handleFileError(error, file, fileList) {
      // 处理文件上传失败的回调
      console.error("文件上传失败", error);
    },
  },
};
</script>

<style>
/* 可以根据需要添加样式 */
</style>