Question

我想在我的JS代码中动态创建一个JSON文件，并调用该文件的下载？

我有机会在JavaScript中做到这一点吗？

谢谢！

Answer 1

如果你不担心，可以使用服务器端语言和GET变量（不要忘记将MIME类型设置为类似application/octet-stream）或base64将JSON编码为Data URI支持旧版浏览器。

这是一个例子;尝试写一些文字，然后按下载。唯一的问题是你无法控制文件名：

<!DOCTYPE HTML>
<html>
  <head>
    <title>Data URI</title>
    <script>
      var Base64 = {

  // private property
  _keyStr : "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=",

  // public method for encoding
  encode : function (input) {
    var output = "";
    var chr1, chr2, chr3, enc1, enc2, enc3, enc4;
    var i = 0;

    input = Base64._utf8_encode(input);

    while (i < input.length) {

      chr1 = input.charCodeAt(i++);
      chr2 = input.charCodeAt(i++);
      chr3 = input.charCodeAt(i++);

      enc1 = chr1 >> 2;
      enc2 = ((chr1 & 3) << 4) | (chr2 >> 4);
      enc3 = ((chr2 & 15) << 2) | (chr3 >> 6);
      enc4 = chr3 & 63;

      if (isNaN(chr2)) {
        enc3 = enc4 = 64;
      } else if (isNaN(chr3)) {
        enc4 = 64;
      }

      output = output +
      this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
      this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4);

    }

    return output;
  },

  // public method for decoding
  decode : function (input) {
    var output = "";
    var chr1, chr2, chr3;
    var enc1, enc2, enc3, enc4;
    var i = 0;

    input = input.replace(/[^A-Za-z0-9\+\/\=]/g, "");

    while (i < input.length) {

      enc1 = this._keyStr.indexOf(input.charAt(i++));
      enc2 = this._keyStr.indexOf(input.charAt(i++));
      enc3 = this._keyStr.indexOf(input.charAt(i++));
      enc4 = this._keyStr.indexOf(input.charAt(i++));

      chr1 = (enc1 << 2) | (enc2 >> 4);
      chr2 = ((enc2 & 15) << 4) | (enc3 >> 2);
      chr3 = ((enc3 & 3) << 6) | enc4;

      output = output + String.fromCharCode(chr1);

      if (enc3 != 64) {
        output = output + String.fromCharCode(chr2);
      }
      if (enc4 != 64) {
        output = output + String.fromCharCode(chr3);
      }

    }

    output = Base64._utf8_decode(output);

    return output;

  },

  // private method for UTF-8 encoding
  _utf8_encode : function (string) {
    string = string.replace(/\r\n/g,"\n");
    var utftext = "";

    for (var n = 0; n < string.length; n++) {

      var c = string.charCodeAt(n);

      if (c < 128) {
        utftext += String.fromCharCode(c);
      }
      else if((c > 127) && (c < 2048)) {
        utftext += String.fromCharCode((c >> 6) | 192);
        utftext += String.fromCharCode((c & 63) | 128);
      }
      else {
        utftext += String.fromCharCode((c >> 12) | 224);
        utftext += String.fromCharCode(((c >> 6) & 63) | 128);
        utftext += String.fromCharCode((c & 63) | 128);
      }

    }

    return utftext;
  },

  // private method for UTF-8 decoding
  _utf8_decode : function (utftext) {
    var string = "";
    var i = 0;
    var c = c1 = c2 = 0;

    while ( i < utftext.length ) {

      c = utftext.charCodeAt(i);

      if (c < 128) {
        string += String.fromCharCode(c);
        i++;
      }
      else if((c > 191) && (c < 224)) {
        c2 = utftext.charCodeAt(i+1);
        string += String.fromCharCode(((c & 31) << 6) | (c2 & 63));
        i += 2;
      }
      else {
        c2 = utftext.charCodeAt(i+1);
        c3 = utftext.charCodeAt(i+2);
        string += String.fromCharCode(((c & 15) << 12) | ((c2 & 63) << 6) | (c3 & 63));
        i += 3;
      }

    }

    return string;
  }

}
      window.onload=function(){
        document.getElementById('download').onclick=function(){
          window.open("data:application/octet-stream;base64,"+Base64.encode(document.getElementById('text').value));
        }
      }
    </script>
  </head>
  <body style="margin:0;padding:0;overflow:hidden;">
    <textarea id="text"></textarea>
    <input type="button" value="Download" style="height:auto;width:100px" id="download"/>
  </body>
</html>

Answer 2

是的，但是您需要将此文件创建为字符串。然后，致电：

window.location = window.URL.createObjectURL(new Blob([what_is_in_your_file], {type: "application/json"}));

Answer 3

您可以创建一个下载按钮，然后...在您的javascript代码中，生成JSON文件并下载，就像这样：

HTML CODE（下载按钮，为“ a”标签）：

<a id="exportJSONbtn" onclick="exportJson()">

然后在您的JS函数中：

function exportJson(){
 var el = document.getElementById('exportJSONbtn'); //id of your download button
        var jsonCreated = { "elements": [] }; //JSON we want to use / create 
        var data = "text/json;charset=utf-8," + encodeURIComponent(JSON.stringify(jsonCreated));
        el.setAttribute("href", "data:" + data);
        el.setAttribute("download", "jsonCreatedFile.json"); //file name
}

使用JavaScript创建文件并调用下载

3 个答案: