【前端】Vue之使用new Blob() 实现不同类型的文件下载

    在 Vue 项目实际开发过程中，经常需要对各种各样的类型进行下载，因为我不是前端出生，就自己在网上学习最后使用到自己的项目当中，代码冗余等低级错误还请多多指导。我发现用 Blob 二进制进行文件下载的比较多，我就采用了这一方式。

    下面是一份 Blob 的配置关系对应表，在我们使用Blob做下载功能时 ，根据需要下载的文件类型修改 type 值进行下载即可。

文件后缀名、文件类型、mimeType值对应关系表

后缀名 文件类型类型（type）.xlsMicrosoft Excelapplication/vnd.ms-excel.xlsxMicrosoft Excel (OpenXML)application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.csvCSVtext/csv.docMicrosoft Wordapplication/msword.docxMicrosoft Word (OpenXML)application/vnd.openxmlformats-officedocument.wordprocessingml.document.pdfPDFapplication/pdf.pptMicrosoft PowerPointapplication/vnd.ms-powerpoint.pptxMicrosoft PowerPoint (OpenXML)application/vnd.openxmlformats-officedocument.presentationml.presentation.png便携式网络图形（PNG）image/png.gifGIFimage/gif.jpegJPEG 图片image/jpeg.jpgJPEG 图片image/jpeg.mp3MP3 音频audio/mpeg.aacAAC 音频audio/aac.html超文本标记语言 (HTML)text/html.cssCSStext/css.jsJavaScripttext/javascript.jsonJSON 格式application/json.abwAbiWord 文档application/x-abiword.arc存档文档(多个文件嵌入)application/x-freearc.aviAVI: 音频视频交错video/x-msvideo.azw亚马逊Kindle电子书格式application/vnd.amazon.ebook.bin任何类型的二进制数据application/octet-stream.bmpWindows OS/2位图图形image/bmp.bzBZip 存档application/x-bzip.bz2BZip2 存档application/x-bzip2.cshC-Shell 脚本application/x-csh.eotMS嵌入式OpenType字体application/vnd.ms-fontobject.epub电子出版物(EPUB)application/epub+zip.htm超文本标记语言 (HTML)text/html.icoIcon 格式image/vnd.microsoft.icon.icsiCalendar 格式text/calendar.jarJava Archive (JAR)application/java-archive.jsonldJSON-LD 格式application/ld+json.mid乐器数字接口(MIDI)audio/midi audio/x-midi.midi乐器数字接口(MIDI)audio/midi audio/x-midi.mjsJavaScript 模块text/javascript.mpegMPEG 视频video/mpeg.mpkg苹果安装程序包application/vnd.apple.installer+xml.odpOpenDocument演示文档application/vnd.oasis.opendocument.presentation.odsOpenDocument 电子表格文件application/vnd.oasis.opendocument.spreadsheet.odtOpenDocument 文本文档application/vnd.oasis.opendocument.text.ogaOGG 音频audio/ogg.ogvOGG 视频video/ogg.ogxOGGapplication/ogg.otfOpenType 字体font/otf.rarRAR 存档application/x-rar-compressed.rtf富文本格式 (RTF)application/rtf.shBourne shell 脚本application/x-sh.svg可缩放矢量图形 (SVG)image/svg+xml.swf小型web格式 (SWF) or Adobe Flash documentapplication/x-shockwave-flash.tarTape 归档(TAR)application/x-tar.tif标记图像文件格式 (TIFF)image/tiff.tiffTagged Image File Format (TIFF)image/tiff.ttfTrueType 字体font/ttf.txtTexttext/plain.vsdMicrosoft Visioapplication/vnd.visio.wav波形音频格式audio/wav.webaWEBM 音频audio/webm.webmWEBM 视频video/webm.webpWEBP 图片image/webp.woff网页开放字体格式 (WOFF)font/woff.woff2网页开放字体格式 (WOFF)font/woff2.xhtmlXHTMLapplication/xhtml+xml.xmlXMLapplication/xml（普通用户不可读）、text/xml（普通用户可.xulXULapplication/vnd.mozilla.xul+xml.zipZIPapplication/zip.3gp3GPP audio/video 容器video/3gpp、audio/3gpp（不含视频）.3g23GPP2 audio/video 容器video/3gpp2、audio/3gpp2（不含视频）.7z7-zipapplication/x-7z-compressed
代码实现

HTML

文件下载按钮，data中定义的我就没有写了哈，自己定义就好了。

<el-button icon="el-icon-search" v-model="formDetail.downloadAddress" :style="{width: '60%'}" class="underline"                        @click="downloadExample(formDetail.assetNo,formDetail.downloadAddress)">点击下载
                </el-button>

JavaScript

    项目中后端返回的是文件上传成功生成的一个字符串，为了保证可以下载所有文件，需要对后缀进行截取进行判断然后取不同的new Blob，这里new Blob中后端直接返回的是文件流，所以直接用res进行获取

downloadExample(assetNo,downloadAddress){
       axios({
            method: "get",
            url: '/dev-api/directory/io/exportdemo?assetNo=' + assetNo + '&fileNo=' + downloadAddress,
            data: "",
            responseType: "blob", // 指定响应类型为二进制数据
          }).then((res) => {
        // 下载格式为zip { type: "application/zip" }
        let suffix = downloadAddress.substring(downloadAddress.lastIndexOf("."))
        if (suffix=='.xls'){
          let blob = new Blob([res], {type: "application/vnd.ms-excel"});
          this.ways(blob,suffix);
        }else if (suffix=='.xlsx'){
          let blob = new Blob([res], {type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"});
          this.ways(blob,suffix);
        }else if (suffix=='.doc'){
          let blob = new Blob([res], {type: "application/msword"});
          this.ways(blob,suffix);
        }else if (suffix=='.docx'){
          let blob = new Blob([res], {type: "application/vnd.openxmlformats-officedocument.wordprocessingml.document"});
          this.ways(blob,suffix);
        }else if (suffix=='.png'){
          let blob = new Blob([res], {type: "pplication/pdf"});
          this.ways(blob,suffix);
        }else if (suffix=='.ppt'){
          let blob = new Blob([res], {type: "application/vnd.ms-powerpoint"});
          this.ways(blob,suffix);
        }else if (suffix=='.png'){
          let blob = new Blob([res], {type: "image/png"});
          this.ways(blob)
        }else if (suffix=='.pptx'){
          let blob = new Blob([res], {type: "application/vnd.openxmlformats-officedocument.presentationml.presentation"});
          this.ways(blob,suffix);
        }else if (suffix=='.jpeg'){
          let blob = new Blob([res], {type: "image/jpeg"});
          this.ways(blob,suffix);
        }else if (suffix=='.zip'){
          let blob = new Blob([res], {type: "application/zip"});
          this.ways(blob,suffix);
        }else if (suffix=='.7z'){
          let blob = new Blob([res], {type: "application/x-7z-compressed"});
          this.ways(blob,suffix);
        }else if (suffix=='tar'){
          let blob = new Blob([res], {type: "application/x-tar"});
          this.ways(blob,suffix);
        }else if (suffix=='.7z'){
          let blob = new Blob([res], {type: "application/x-7z-compressed"});
          this.ways(blob,suffix);
        }
      })
    },
   
    ways(blob, suffix,res) {
      let elink = document.createElement("a");   // 创建一个<a>标签
      elink.style.display = "none";                       // 隐藏标签
      elink.href = window.URL.createObjectURL(blob);      // 配置href
      // 获取后端返回的响应头中的名称
      let filename = res.headers["content-disposition"]; 
      let newFilename = filename.split(';')[1].split('=')[1];

      //自定义名称
      // let newFilename = "样例文件" + new Date().getTime() + suffix; //自定义名字

      // let newFilename = decodeURIComponent(res.headers["content-disposition"].split(';')[1].split('=')[1])
      newFilename = decodeURIComponent(newFilename);
      elink.download = newFilename;
      elink.click();
      URL.revokeObjectURL(elink.href);   // 释放URL 对象(弹出框进行下载)
      document.body.removeChild(elink);  // 移除<a>标签
    },

拓展:如果想获取响应头中的信息比如

直接使用

res.headers["XXX"];进行获取即可。

这样就可以实现各种类型的文件的下载了，很巴适。