下载文件改名

不同源的话需要后台跨域,否则无法下载

downUpdateFileName(url, fileName) {
    const x = new XMLHttpRequest()
    x.open("GET", url, true)
    x.responseType = 'blob'
    x.onload=function(e) {
        const url = window.URL.createObjectURL(x.response)
        const a = document.createElement('a')
        a.href = url
        a.target = '_blank'
        a.download = fileName
        a.click()
        a.remove()
    }
    x.send()
}