vue下载图片和跨域下载图片

1.如果知道了网络的url,进行下载

(1).方式1:使用h5的标签，一定要写href和download，href指向的是目标url，download可以指定下载的文件名

<a :href="url" target="_blank" download>
         <el-button size="small" type="primary">下载</el-button>
</a>

(2)方式2:

      <a id="fileUrl" style="display: none"/>

  downloadFile() {
      var fileName = this.getFileName(this.resourcesContent)
      const fileUrl = document.getElementById('fileUrl')
      fileUrl.setAttribute('href', this.url)
      fileUrl.setAttribute('download', 'xxx.xls')
      fileUrl.click()
    },

2.同源下载，文件放在前端的/src/assets文件夹下

在data定义的变量:

 imgSrc: 'http://' + window.location.host + '/src/assets/images/logo-2.png',

定义的按钮

              <img :src="imgSrc" alt="">
              <a :href="imgSrc" target="_blank" download>
                <el-button size="small" type="primary">下载</el-button>
              </a>

3.跨域下载文件

downloadImage() {
      const src = this.url
      var fileName = this.getFileName(this.url)
      var canvas = document.createElement('canvas')
      var img = document.createElement('img')
      img.onload = function(e) {
        canvas.width = img.width
        canvas.height = img.height
        var context = canvas.getContext('2d')
        context.drawImage(img, 0, 0, img.width, img.height)
        canvas.getContext('2d').drawImage(img, 0, 0, img.width, img.height)
        canvas.toBlob((blob) => {
          const link = document.createElement('a')
          link.href = window.URL.createObjectURL(blob)
          link.download = fileName
          link.click()
        }, 'image/jpeg')
      }
      img.setAttribute('crossOrigin', 'Anonymous')
      img.src = src
    },
    getFileName(url) {
      var urlSlashCount = url.split('/').length
      return url.split('/')[urlSlashCount - 1].toLowerCase()
    },