- var aBlob = new Blob( array, options );
兼容性
mimeType[2]
在 Blob 的构造函数中options参数的接受一个参数type,这个参数代表的是媒体类型,告诉浏览器是什么类型的文件,常见的有
- {".3gp", "video/3gpp"},
- {".apk", "application/vnd.android.package-archive"},
- {".asf", "video/x-ms-asf"},
- {".avi", "video/x-msvideo"},
- {".bin", "application/octet-stream"},
- {".bmp", "image/bmp"},
- {".c", "text/plain"},
- {".class", "application/octet-stream"},
- {".conf", "text/plain"},
- {".cpp", "text/plain"},
- {".doc", "application/msword"},
- {".docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document"},
- {".xls", "application/vnd.ms-excel"},
- {".xlsx", "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"},
- {".exe", "application/octet-stream"},
- {".gif", "image/gif"},
- {".gtar", "application/x-gtar"},
- {".gz", "application/x-gzip"},
- {".h", "text/plain"},
- {".htm", "text/html"},
- {".html", "text/html"},
- {".jar", "application/java-archive"},
- {".java", "text/plain"},
- {".jpeg", "image/jpeg"},
- {".jpg", "image/jpeg"},
- {".js", "application/x-javascript"},
- {".log", "text/plain"},
- {".m3u", "audio/x-mpegurl"},
- {".m4a", "audio/mp4a-latm"},
- {".m4b", "audio/mp4a-latm"},
- {".m4p", "audio/mp4a-latm"},
- {".m4u", "video/vnd.mpegurl"},
- {".m4v", "video/x-m4v"},
- {".mov", "video/quicktime"},
- {".mp2", "audio/x-mpeg"},
- {".mp3", "audio/x-mpeg"},
- {".mp4", "video/mp4"},
- {".mpc", "application/vnd.mpohun.certificate"},
- {".mpe", "video/mpeg"},
- {".mpeg", "video/mpeg"},
- {".mpg", "video/mpeg"},
- {".mpg4", "video/mp4"},
- {".mpga", "audio/mpeg"},
- {".msg", "application/vnd.ms-outlook"},
- {".ogg", "audio/ogg"},
- {".pdf", "application/pdf"},
- {".png", "image/png"},
- {".pps", "application/vnd.ms-powerpoint"},
- {".ppt", "application/vnd.ms-powerpoint"},
- {".pptx", "application/vnd.openxmlformats-officedocument.presentationml.presentation"},
- {".prop", "text/plain"},
- {".rc", "text/plain"},
- {".rmvb", "audio/x-pn-realaudio"},
- {".rtf", "application/rtf"},
- {".sh", "text/plain"},
- {".tar", "application/x-tar"},
- {".tgz", "application/x-compressed"},
- {".txt", "text/plain"},
- {".wav", "audio/x-wav"},
- {".wma", "audio/x-ms-wma"},
- {".wmv", "audio/x-ms-wmv"},
- {".wps", "application/vnd.ms-works"},
- {".xml", "text/plain"},
- {".z", "application/x-compress"},
- {".zip", "application/x-zip-compressed"},
- {"", "*/*"}
导出
我们需要调取接口来获取导出文件的内容,如果我们先后端分离的话,我们需要接口给我们返回Buffer, Blob, DOMString类型的数据,DOMStrings会被编码为UTF-8。
- let blob = new Blob([接口返回的数据], {
- type: "application/vnd.ms-excel;charset=utf-8"
- });
使用a标签,模拟点击a标签完成导出功能,通过URL.createObjectURL()[3]方法创建一个下载的链接地址,最后在不需要的时候URL.revokeObjectURL释放掉
- let downloadElement = document.createElement("a");
- let href = window.URL.createObjectURL(blob); //创建下载的链接
- downloadElement.href = href;
- document.body.appendChild(downloadElement);
- downloadElement.click(); //点击下载
- document.body.removeChild(downloadElement); //下载完成移除元素
- window.URL.revokeObjectURL(href); //释放掉blob对象
文件名的设置
文件名称通过报文头设置content-disposition属性设置,Content-Disposition参数:
- attachment --- 作为附件下载
- inline --- 在线打开
- setHeader("Content-Disposition","inline; filename=文件名.mp3");
- setHeader("Content-Disposition","attachment;filename=test.xls");
前端通过截取报文头里的content-disposition字段获取文件名称:
- downloadElement.download =decodeURI(
- res.headers["content-disposition"].split("filename=")[1]
- ) || ""; //下载后文件名
完整代码
这里的res代表后台返回的数据:
- config: {url: "/ExportExcel", method: "post", data: "", headers: {…}, baseURL: "/api/", …}
- data: Blob {size: 5120, type: "application/vnd.ms-excel"}
- headers: {connection: "close", content-disposition: "attachment;filename=xxx.xls", content-encoding: "gzip", content-length: "1455", content-type: "application/vnd.ms-excel;charset=UTF-8", …}
- request: XMLHttpRequest {readyState: 4, timeout: 30000, withCredentials: false, upload: XMLHttpRequestUpload, onreadystatechange: ƒ, …}
- status: 200
- statusText: "OK"
前端代码
- let blob = new Blob([res.data], {
- type: "application/vnd.ms-excel;charset=utf-8"
- });
- let downloadElement = document.createElement("a");
- let href = window.URL.createObjectURL(blob); //创建下载的链接
- downloadElement.href = href;
- downloadElement.download =
- decodeURI(
- res.headers["content-disposition"].split("filename=")[1]
- ) || ""; //下载后文件名
- document.body.appendChild(downloadElement);
- downloadElement.click(); //点击下载
- document.body.removeChild(downloadElement); //下载完成移除元素
- window.URL.revokeObjectURL(href); //释放掉blob对象
写在最后
导出功能多种多样,根据浏览器的不同和需求的不同会有不同的问题出现其中的坑还是比较多的,适合自己需求的才是最好的。