用JS 七牛上传图片出现文件已存在的错误（file exists）,可明明是第一次上传，而且我有更改key值，如果把本地文件名改了就又不会报错了
用官方的demo也会报错http://jssdk.demo.qiniu.io/#

var uploader_pub = Qiniu.uploader({
        runtimes: 'html5,flash,html4',
        browse_button: 'public_pickfiles',
        container: 'container',
        drop_element: 'public_pickfiles',
        max_file_size: '15mb',
        flash_swf_url: 'bower_components/plupload/js/Moxie.swf',
        dragdrop: true,
        max_retries:3,
        chunk_size: '4mb',
        multi_selection: !(mOxie.Env.OS.toLowerCase()==="ios"),
        uptoken_func: function(){
          
          
        },
        multi_selection: true,
        unique_names: false,
        save_key: false,
      domain: $('#public_domain').val(),
      get_new_uptoken: false,
      auto_start: false,
      //unique_names: true,      //设置所有文件名唯一
      filters: {  
        mime_types : [ //只允许上传图片  
            { title : "Image files", extensions : "jpg,jpeg,gif,png" },  
        ],  
        prevent_duplicates : false //不允许选取重复文件  
      },  
      log_level: 5,
        init: {
            'Key': function(up, file) {
              var now = new Date();
                    var date = now.getFullYear()+((now.getMonth()+1)<10?"0":"")+(now.getMonth()+1)+(now.getDate()<10?"0":"")+now.getDate();
                    var lastimg="work/"+date+"/"+getFileName(file.name);
            return lastimg;
              },
          'FileUploaded': function(up, file, info) {
                var progress = new FileProgress(file, 'public_fs');
                info = eval('('+info+')');
                var imgKey = encodeURI($("#public_domain").val()+info.key);
                imageFile.push({image:imgKey+"",isLayer:false})
                coverHash.push({hash:info.hash,key:info.key})

            },
          'FilesAdded': function(up, files) {
                plupload.each(files,function(file,index) {
                  var tempArr = file.name.split(".");
                  var ext;
                  if (tempArr.length === 1 || (tempArr[0] === "" && tempArr.length === 2)) {
                    ext = "";
                  } else {
                    ext = tempArr.pop().toLowerCase(  ); //get the extension and make it lower-case
                  }
                  var now = new Date();
                  var date = now.getFullYear()+((now.getMonth()+1)<10?"0":"")+(now.getMonth()+1)+(now.getDate()<10?"0":"")+now.getDate();
                  var keyName="work/"+date+"/"+getTimeHSS()+"/"+index+"."+ext;
                  file.name=keyName;
                  var reader = new FileReader();
                        reader.readAsDataURL(files[0].getNative());
                        reader.onload = (function (e) {
                          var image = new Image();
                          image.src = e.target.result;
                          image.onload = function (){
                              file.width = this.width;
                              file.height = this.height;
                          };
                        });
                });

                //图片上传前预览
                for (var i = 0; i < files.length; i++) {
                    var fileItem = files[i].getNative(),
                    url = window.URL || window.webkitURL || window.mozURL;
                    var src = url.createObjectURL(fileItem);
                    var tmpl = '
';
                    $(".public_add_more").before($(tmpl.replace(/#url#/ig, src)));
                }
                if($('#public_fs li').length>0){
                    $('#public_fs').removeClass('img_area_back');
                    $('.public_add_more').css('display','block');
                }
                if($('#public_fs li').length>=9){
                    $('.public_add_more').css('display','none');
                }
                      var sss = uploader_pub.files;
              console.log(sss)
                      if(sss.length>9) { // 最多上传9张图
                  swal({
                    text: '最多只能上传9张图',
                    showConfirmButton:false,
                    target:'.mySwl_box',
                    width:'auto',
                    timer:1000,
                    animation:false,
                  }).catch(swal.noop)
                  var i = 0;
                  $('#public_fs li').each(function(){
                        i++
                  })
                  uploader_pub.files.splice(9,uploader_pub.files.length)
                    if (i>8) {
                        $("#public_fs li:gt(8)").remove();
                    }
                  return;
              }else{
                isRepeat(sss)
              }
              function isRepeat(arr){
                for( var i=0;i255){
                  $('.loading').css('display','none');
                  swal({
                    text:'表情描述不能超过255个字~',
                    showConfirmButton:false,
                    target:'.mySwl_box',
                    width:'auto',
                    timer:1000,
                    animation:false,
                  }).catch(swal.noop)
                }else{
                  if (coverHash.length!=0 ) {
                    if(imageFile.length==1){
                      var coverHash_one=coverHash[0].hash;
                      $.ajax({
                        type:'post',
                        url:'/setting/cheackHash',
                        data:{hash:coverHash_one},
                        success:function(data){
                          if(data.code==200){
                            $('#pub_imageFile').val(images);
                            $('#pub_coverHash').val(coverHash_one);
                            cookieTopic(str_content)
                            $.ajax({
                                type:'post',
                                url:'/imgupload',
                                data:{content:str_content,imagedata:images,coverHash:coverHash_one},
                                success:function(data){
                                    $('.loading').css('display','none');
                                    if(data.code==200){
                                        swal({
                                          text:'发布成功~',
                                          showConfirmButton:false,
                                          target:'.mySwl_box',
                                          width:'auto',
                                          timer:1400,
                                          animation:false,
                                        }).catch(swal.noop)
                                        //初始化
                                        updataInit()
                                        //初始化 end$('.created-topic').fadeOut('fast')
                                        $('.fabu').fadeOut('fast')
                                        window.location.href='/user/'+userId
                                    }else{
                                        coverHash =[];
                                        imageFile = [];
                                        uploader_pub.files.splice(0,uploader_pub.files.length);
                                        $('.public_add_imgarea').find('.public_add_more').css('display','block')
                                        $('.public_add_imgarea>li').remove();
                                        swal({
                                          text: data.msg,
                                          showConfirmButton:false,
                                          target:'.mySwl_box',
                                          width:'auto',
                                          timer:1000,
                                          animation:false,
                                        }).catch(swal.noop)
                                    }
                                    $('.loading').css('display','none');
                                }
                            });
                          }else{
                            $('.loading').css('display','none');
                            swal({
                              text:data.msg,
                              showConfirmButton:false,
                              target:'.mySwl_box',
                              width:'auto',
                              timer:1400,
                              animation:false,
                            }).catch(swal.noop)
                            //初始化
                            updataInit()
                          }
                        }//success
                      })
                    }else{
                      var coverHash_one=coverHash[0].hash;
                      $('#pub_imageFile').val(images);
                      $('#pub_coverHash').val(coverHash_one);
                      cookieTopic(str_content)
                      $.ajax({
                          type:'post',
                          url:'/imgupload',
                          data:{content:str_content,imagedata:images,coverHash:coverHash_one},
                          success:function(data){
                              if(data.code==200){
                                  swal({
                                    text:'发布成功~',
                                    showConfirmButton:false,
                                    target:'.mySwl_box',
                                    width:'auto',
                                    timer:1400,
                                    animation:false,
                                  }).catch(swal.noop)
                                  //初始化
                                  updataInit()
                                  //初始化 end
                                  $('.fabu').fadeOut('fast')
                                  // window.location.href='/user/'+userId
                              }else{
                                  coverHash =[];
                                  imageFile = [];
                                  uploader_pub.files.splice(0,uploader_pub.files.length);
                                  $('.public_add_imgarea').find('.public_add_more').css('display','block')
                                  $('.public_add_imgarea>li').remove();
                                  swal({
                                    text: data.msg,
                                    showConfirmButton:false,
                                    target:'.mySwl_box',
                                    width:'auto',
                                    timer:1000,
                                    animation:false,
                                  }).catch(swal.noop)
                              }
                              $('.loading').css('display','none');
                          }
                      });
                    }
                    
                  } else{
                    $('.loading').css('display','none');
                    swal({
                      text: '请上传图片',
                      showConfirmButton:false,
                      target:'.mySwl_box',
                      width:'auto',
                      timer:1000,
                      animation:false,
                    }).catch(swal.noop)
                  }
                }
            },
            'Error': function(up, err, errTip) {
               $('.loading').css('display','none');
               console.log(err)
               
            }
        }
    });