JavaScript Base64 作为文件上传的实例代码解析

た入场券 2021-12-12 16:21 136阅读 0赞

image标签src的格式有时候会是base64如下：

首先需要 吧 base64 流转换成 blob 对象，文件对象都继承它。

剩下的就作为文件上传了

let $Blob = new Blob([new Uint8Array(array)], {type:'image/jpeg' });
    let formData = new FormData();
    formData.append("files", $Blob ,"file_"+ Date.parse(new Date()) + ".jpg");

完整代码：

<!DOCTYPE html> 
    <html> 
    <head> 
      <meta http-equiv="Content-Type" content="text/html; charset=utf-8"/> 
      <title>上传用例</title> 
      <meta content='width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no' name='viewport'> 
      <script type="text/javascript"> 
        /** 
         * 根据base64 内容 取得 bolb 
         * 
         * @param dataURI 
         * @returns Blob 
         */
        function getBlobBydataURI(dataURI,type) { 
          var binary = atob(dataURI.split(',')[1]); 
          var array = []; 
          for(var i = 0; i < binary.length; i++) { 
            array.push(binary.charCodeAt(i)); 
          } 
          return new Blob([new Uint8Array(array)], {type:type }); 
        } 
        /** 
         * 上传 
         */
        function upload(){ 
          //base64 转 blob 
          var $Blob= getBlobBydataURI(document.getElementsByTagName("img")[0].currentSrc,'image/jpeg'); 
          var formData = new FormData(); 
          formData.append("files", $Blob ,"file_"+Date.parse(new Date())+".jpeg"); 
          //组建XMLHttpRequest 上传文件 
          var request = new XMLHttpRequest(); 
          //上传连接地址 
          request.open("POST", "www.xxx.com"); 
          request.onreadystatechange=function() 
          { 
            if (request.readyState==4) 
            { 
              if(request.status==200){ 
                console.log("上传成功"); 
              }else{ 
                console.log("上传失败,检查上传地址是否正确"); 
              } 
            } 
          } 
          request.send(formData); 
        } 
      </script> 
    </head> 
    <body> 
    <button οnclick="upload()">上传测试</button> 
    <br /> 
    上传的图片: 
    <img src="data:image/jpeg;base64,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" /> 
    </body> 
    </html>

转载于:https://www.cnblogs.com/wx790868181/p/11041969.html