JS FileReader: Read CSV from Local File & jquery-csv

问题

I have a CSV file in the same directory as an html page, and I'd like to use FileReader to read the file contents into a jquery-csv's To Arrays function, but I can't seem to get it to work properly. I think I understand the asynchrony of this task, but have i depicted it correctly? Here, I'm trying to output the 2nd cell in the 2nd column. Thanks for any help.

<script type="text/javascript" src="https://www.google.com/jsapi?autoload={'modules':[{'name':'visualization','version':'1','packages':['timeline']}]}"></script>

<script src="https://code.jquery.com/jquery-1.9.1.min.js"></script>
<script src="jquery.csv-0.71.js"></script>
<script type="text/javascript">

var reader = new FileReader();

reader.onload = function(e) {
  var text = e.target.result;
  var data = $.csv.toArrays(text);
  document.write(data[1][1]);

}

reader.readAsText('data.csv');




</script>

回答1:

It's not going to work.You have no permissions to read files with javascript from the browser. The only way to deal with it is to create an input[type=file] tag and add onChange event to it. For example:

document.getElementById('fileupload').addEventListener('change', function (e) {
  var files = e.target.files;
  //proceed your files here
  reader.readAsText(files[0]);
}, false);

回答2:

Here's a working demo provided by jquery-csv

<html>
<head>
<meta charset="utf-8" />
<title>Demo - CSV-to-Table</title>
</head>

<body>
  <div id="inputs" class="clearfix">
    <input type="file" id="files" name="files[]" multiple />
  </div>
  <hr />
  <output id="list">
  </output>
  <hr />
  <table id="contents" style="width:100%; height:400px;" border>
  </table>

  <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.8.2/jquery.min.js"></script>
  <script src="http://evanplaice.github.io/jquery-csv/src/jquery.csv.min.js"></script>
  <script>
    $(document).ready(function() {
      if(isAPIAvailable()) {
        $('#files').bind('change', handleFileSelect);
      }
    });

    function isAPIAvailable() {
      // Check for the various File API support.
      if (window.File && window.FileReader && window.FileList && window.Blob) {
        // Great success! All the File APIs are supported.
        return true;
      } else {
        // source: File API availability - http://caniuse.com/#feat=fileapi
        // source: <output> availability - http://html5doctor.com/the-output-element/
        document.writeln('The HTML5 APIs used in this form are only available in the following browsers:<br />');
        // 6.0 File API & 13.0 <output>
        document.writeln(' - Google Chrome: 13.0 or later<br />');
        // 3.6 File API & 6.0 <output>
        document.writeln(' - Mozilla Firefox: 6.0 or later<br />');
        // 10.0 File API & 10.0 <output>
        document.writeln(' - Internet Explorer: Not supported (partial support expected in 10.0)<br />');
        // ? File API & 5.1 <output>
        document.writeln(' - Safari: Not supported<br />');
        // ? File API & 9.2 <output>
        document.writeln(' - Opera: Not supported');
        return false;
      }
    }

    function handleFileSelect(evt) {
      var files = evt.target.files; // FileList object
      var file = files[0];

      // read the file metadata
      var output = ''
          output += '<span style="font-weight:bold;">' + escape(file.name) + '</span><br />\n';
          output += ' - FileType: ' + (file.type || 'n/a') + '<br />\n';
          output += ' - FileSize: ' + file.size + ' bytes<br />\n';
          output += ' - LastModified: ' + (file.lastModifiedDate ? file.lastModifiedDate.toLocaleDateString() : 'n/a') + '<br />\n';

      // read the file contents
      printTable(file);

      // post the results
      $('#list').append(output);
    }

    function printTable(file) {
      var reader = new FileReader();
      reader.readAsText(file);
      reader.onload = function(event){
        var csv = event.target.result;
        var data = $.csv.toArrays(csv);
        var html = '';
        for(var row in data) {
          html += '<tr>\r\n';
          for(var item in data[row]) {
            html += '<td>' + data[row][item] + '</td>\r\n';
          }
          html += '</tr>\r\n';
        }
        $('#contents').html(html);
      };
      reader.onerror = function(){ alert('Unable to read ' + file.fileName); };
    }
  </script>
</body>
</html>

Disclaimer: I'm the author of jquery-csv

来源：https://stackoverflow.com/questions/30223361/js-filereader-read-csv-from-local-file-jquery-csv

标签

javascript

csv

filereader

jquery-csv