将文件从文件上传转换为 base64

Question

我在 extjs 'fileuploadfield' (Ext.form.field.File) 中使用文件上传器，在我的按钮处理程序中我想将其上传为 base64

    handler: function(){
        if(self.getForm().isValid()){
            self.getForm().submit({
                url: myURL,
                headers: {
                    'Accept': 'application/json; charset=utf-8'
                },

我想要这样的东西:

handler: function(){
    if(self.getForm().isValid()){

        var f = self.getForm().getFileStream();

        var base64 = convertToBase64(f);

        var params = {};
        params.base64 = base64;

        Ext.Ajax.request({
            params: params,
            scope: this,
            url: myURL,
            method: 'POST',
            callback: function (options, success, response) {

            }
        )
    }

我从哪里获取表单对象的文件数据？我可以用什么来转换成base64？我处理这个问题的逻辑是否正确？

Answer 1

请试试这个。

Ext.onReady(function() {
  Ext.create('Ext.form.field.File', {
    id: 'uploadFile',
    renderTo: 'example-form',
    emptyText: 'Select a file to upload...',
    fieldLabel: 'File upload',
    labelAlign: 'right',
    labelSeparator: ' ',
    buttonText: 'Select file...',
    labelWidth: 107,
    padding: '3 0 0 20',
    width: 400,
    listeners: {
      'change': function(fileUploadComponent, value, eOpts) {
        this.onFileChange(fileUploadComponent, value, eOpts);
      }
    },

    onFileChange: function(fileUploadComponent, value, eOpts) {
      var file = Ext.getCmp('uploadFile').getEl().down('input[type=file]').dom.files[0];
      if (file != null) {
        var reader = new FileReader();
        reader.readAsArrayBuffer(file);
        reader.onloadend = function(oFREvent) {
          var byteArray= new Uint8Array(oFREvent.target.result);
          var len = byteArray.byteLength;
          var binary = '';
          for (var i = 0; i < len; i++) {
            binary += String.fromCharCode(byteArray[i]);
          }
          byteArray= window.btoa(binary);
          alert(byteArray);
        }
      }
    }
  });
});

Java 在 InputStream 中转换它的代码：

public InputStream persistFile(String imageByteArray){
           byte[] byteArray =   com.sun.org.apache.xerces.internal.impl.dv.util.Base64.decode(imageByteArray);
           InputStream is = new ByteArrayInputStream(byteArray);
           return is;
}

这里是fiddle

将文件从文件上传转换为 base64

Converting File from File Upload to base64

extjs

extjs4